ethereum as generic upstream (#331)

- merge all Ethereum implementations to Generic upstreams and multistreams - merge evm-pos and pow to ethereum
2023-10-31 16:28:15 +03:00
parent 4ea4fa5d81
commit 08cbffe7d1
69 changed files with 826 additions and 2790 deletions
--- a/foundation/src/main/kotlin/org/drpc/chainsconfig/ChainsConfig.kt
+++ b/foundation/src/main/kotlin/org/drpc/chainsconfig/ChainsConfig.kt
@@ -33,7 +33,10 @@ data class ChainsConfig(private val chains: List<ChainConfig>) : Iterable<Chains
    ) {
        companion object {
            @JvmStatic
-            fun default() = ChainConfig(
+            fun default() = defaultWithContract(null)
+
+            @JvmStatic
+            fun defaultWithContract(callLimitContract: String?) = ChainConfig(
                Duration.ofSeconds(12),
                6,
                1,
@@ -43,11 +46,14 @@ data class ChainsConfig(private val chains: List<ChainConfig>) : Iterable<Chains
                0,
                "UNKNOWN",
                emptyList(),
-                null,
+                callLimitContract,
                "undefined",
                "undefined",
            )
        }
+
+
+
    }

    fun resolve(chain: String): ChainConfig {
--- a/src/main/kotlin/io/emeraldpay/dshackle/BlockchainType.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/BlockchainType.kt
@@ -1,27 +1,21 @@
 package io.emeraldpay.dshackle

 enum class BlockchainType {
-    BITCOIN, EVM_POW, EVM_POS, STARKNET;
+    BITCOIN, ETHEREUM, STARKNET;

    companion object {
-
-        val pow = setOf(
-            Chain.ETHEREUM_CLASSIC__MAINNET,
-        )
        val bitcoin = setOf(Chain.BITCOIN__MAINNET, Chain.BITCOIN__TESTNET)

        val starknet = setOf(Chain.STARKNET__MAINNET, Chain.STARKNET__TESTNET, Chain.STARKNET__TESTNET_2)

        @JvmStatic
        fun from(chain: Chain): BlockchainType {
-            return if (pow.contains(chain)) {
-                EVM_POW
-            } else if (bitcoin.contains(chain)) {
+            return if (bitcoin.contains(chain)) {
                BITCOIN
            } else if (starknet.contains(chain)) {
                STARKNET
            } else {
-                EVM_POS
+                ETHEREUM
            }
        }
    }
--- a/src/main/kotlin/io/emeraldpay/dshackle/cache/CachesFactory.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/cache/CachesFactory.kt
@@ -97,7 +97,6 @@ open class CachesFactory(
            caches.setReceipts(ReceiptRedisCache(redis.reactive(), chain))
            caches.setHeightByHash(HeightByHashRedisCache(redis.reactive(), chain))
        }
-        caches.setCacheEnabled(cacheConfig.requestsCacheEnabled)
        return caches.build()
    }

--- a/src/main/kotlin/io/emeraldpay/dshackle/config/CacheConfig.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/config/CacheConfig.kt
@@ -17,8 +17,6 @@ package io.emeraldpay.dshackle.config

 class CacheConfig {

-    var requestsCacheEnabled = true
-
    var redis: Redis? = null

    class Redis(
--- a/src/main/kotlin/io/emeraldpay/dshackle/config/CacheConfigReader.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/config/CacheConfigReader.kt
@@ -16,21 +16,13 @@
 package io.emeraldpay.dshackle.config

 import io.emeraldpay.dshackle.foundation.YamlConfigReader
-import org.slf4j.LoggerFactory
 import org.yaml.snakeyaml.nodes.MappingNode

 class CacheConfigReader : YamlConfigReader<CacheConfig>() {

-    companion object {
-        private val log = LoggerFactory.getLogger(CacheConfigReader::class.java)
-    }
-
    override fun read(input: MappingNode?): CacheConfig? {
        return getMapping(input, "cache")?.let { node ->
            val config = CacheConfig()
-            getValueAsBool(node, "requests-cache-enabled")?.let {
-                config.requestsCacheEnabled = it
-            }
            getMapping(node, "redis")?.let { redisNode ->
                val redis = CacheConfig.Redis()
                val enabled = getValueAsBool(redisNode, "enabled") ?: true
@@ -50,7 +42,7 @@ class CacheConfigReader : YamlConfigReader<CacheConfig>() {
                    config.redis = redis
                }
            }
-            if (config.redis == null && config.requestsCacheEnabled) {
+            if (config.redis == null) {
                return null
            }
            config
--- a/src/main/kotlin/io/emeraldpay/dshackle/config/TokensConfig.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/config/TokensConfig.kt
@@ -41,7 +41,7 @@ class TokensConfig(
                type == null -> type
                address.isNullOrBlank() -> "address"
                blockchain != null &&
-                    (BlockchainType.from(blockchain!!) == BlockchainType.EVM_POS || BlockchainType.from(blockchain!!) == BlockchainType.EVM_POW) &&
+                    (BlockchainType.from(blockchain!!) == BlockchainType.ETHEREUM) &&
                    !Address.isValidAddress(address) -> "address"
                else -> null
            }
--- a/src/main/kotlin/io/emeraldpay/dshackle/config/context/MultistreamsConfig.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/config/context/MultistreamsConfig.kt
@@ -2,16 +2,12 @@ package io.emeraldpay.dshackle.config.context

 import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.BlockchainType.BITCOIN
-import io.emeraldpay.dshackle.BlockchainType.EVM_POS
-import io.emeraldpay.dshackle.BlockchainType.EVM_POW
-import io.emeraldpay.dshackle.BlockchainType.STARKNET
 import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.cache.CachesFactory
 import io.emeraldpay.dshackle.upstream.CallTargetsHolder
 import io.emeraldpay.dshackle.upstream.Multistream
 import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinMultistream
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumPosMultiStream
+import io.emeraldpay.dshackle.upstream.generic.ChainSpecificRegistry
 import io.emeraldpay.dshackle.upstream.generic.GenericMultistream
 import org.springframework.beans.factory.annotation.Qualifier
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory
@@ -31,14 +27,13 @@ open class MultistreamsConfig(val beanFactory: ConfigurableListableBeanFactory)
        headScheduler: Scheduler,
        tracer: Tracer,
    ): List<Multistream> {
-        return Chain.values()
+        return Chain.entries
            .filterNot { it == Chain.UNSPECIFIED }
            .map { chain ->
-                when (BlockchainType.from(chain)) {
-                    EVM_POS -> ethereumPosMultistream(chain, cachesFactory, headScheduler, tracer)
-                    EVM_POW -> ethereumMultistream(chain, cachesFactory, headScheduler, tracer)
-                    BITCOIN -> bitcoinMultistream(chain, cachesFactory, headScheduler)
-                    STARKNET -> genericMultistream(chain, cachesFactory, headScheduler)
+                if (BlockchainType.from(chain) == BITCOIN) {
+                    bitcoinMultistream(chain, cachesFactory, headScheduler)
+                } else {
+                    genericMultistream(chain, cachesFactory, headScheduler, tracer)
                }
            }
    }
@@ -47,47 +42,18 @@ open class MultistreamsConfig(val beanFactory: ConfigurableListableBeanFactory)
        chain: Chain,
        cachesFactory: CachesFactory,
        headScheduler: Scheduler,
+        tracer: Tracer,
    ): Multistream {
        val name = "multi-$chain"
+        val cs = ChainSpecificRegistry.resolve(chain)
        return GenericMultistream(
            chain,
            CopyOnWriteArrayList(),
            cachesFactory.getCaches(chain),
            headScheduler,
-        ).also { register(it, name) }
-    }
-
-    private fun ethereumMultistream(
-        chain: Chain,
-        cachesFactory: CachesFactory,
-        headScheduler: Scheduler,
-        tracer: Tracer,
-    ): EthereumMultistream {
-        val name = "multi-ethereum-$chain"
-
-        return EthereumMultistream(
-            chain,
-            CopyOnWriteArrayList(),
-            cachesFactory.getCaches(chain),
-            headScheduler,
-            tracer,
-        ).also { register(it, name) }
-    }
-
-    open fun ethereumPosMultistream(
-        chain: Chain,
-        cachesFactory: CachesFactory,
-        headScheduler: Scheduler,
-        tracer: Tracer,
-    ): EthereumPosMultiStream {
-        val name = "multi-ethereum-pos-$chain"
-
-        return EthereumPosMultiStream(
-            chain,
-            CopyOnWriteArrayList(),
-            cachesFactory.getCaches(chain),
-            headScheduler,
-            tracer,
+            cs.makeCachingReaderBuilder(tracer),
+            cs::localReaderBuilder,
+            cs.subscriptionBuilder(headScheduler),
        ).also { register(it, name) }
    }

--- a/src/main/kotlin/io/emeraldpay/dshackle/rpc/NativeCall.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/rpc/NativeCall.kt
@@ -20,7 +20,7 @@ import com.fasterxml.jackson.databind.ObjectMapper
 import com.google.protobuf.ByteString
 import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.dshackle.BlockchainType
-import io.emeraldpay.dshackle.BlockchainType.EVM_POS
+import io.emeraldpay.dshackle.BlockchainType.ETHEREUM
 import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.Global
 import io.emeraldpay.dshackle.Global.Companion.nullValue
@@ -76,7 +76,6 @@ open class NativeCall(
    private val log = LoggerFactory.getLogger(NativeCall::class.java)
    private val objectMapper: ObjectMapper = Global.objectMapper

-    private val localRouterEnabled = config.cache?.requestsCacheEnabled ?: true
    private val passthrough = config.passthrough

    var rpcReaderFactory: RpcReaderFactory = RpcReaderFactory.default()
@@ -85,7 +84,7 @@ open class NativeCall(
    @EventListener
    fun onUpstreamChangeEvent(event: UpstreamChangeEvent) {
        multistreamHolder.getUpstream(event.chain).let { up ->
-            if (BlockchainType.from(up.chain) == EVM_POS) {
+            if (BlockchainType.from(up.chain) == ETHEREUM) {
                ethereumCallSelectors.putIfAbsent(
                    event.chain,
                    EthereumCallSelector(up.caches),
@@ -307,7 +306,7 @@ open class NativeCall(
        }
        // for ethereum the actual block needed for the call may be specified in the call parameters
        val callSpecificMatcher: Mono<Selector.Matcher> =
-            if (BlockchainType.from(upstream.chain) == BlockchainType.EVM_POS || BlockchainType.from(upstream.chain) == BlockchainType.EVM_POW) {
+            if (BlockchainType.from(upstream.chain) == ETHEREUM) {
                ethereumCallSelectors[chain]?.getMatcher(method, params, upstream.getHead(), passthrough)
            } else {
                null
@@ -359,7 +358,7 @@ open class NativeCall(
        if (method in DefaultEthereumMethods.newFilterMethods) CreateFilterDecorator() else NoneResultDecorator()

    fun fetch(ctx: ValidCallContext<ParsedCallDetails>): Mono<CallResult> {
-        return ctx.upstream.getLocalReader(localRouterEnabled)
+        return ctx.upstream.getLocalReader()
            .flatMap { api ->
                SpannedReader(api, tracer, LOCAL_READER)
                    .read(JsonRpcRequest(ctx.payload.method, ctx.payload.params, ctx.nonce, ctx.forwardedSelector))
--- a/src/main/kotlin/io/emeraldpay/dshackle/rpc/NativeSubscribe.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/rpc/NativeSubscribe.kt
@@ -57,7 +57,7 @@ open class NativeSubscribe(

    fun start(request: BlockchainOuterClass.NativeSubscribeRequest): Publisher<ResponseHolder> {
        val chain = Chain.byId(request.chainValue)
-        if (BlockchainType.from(chain) != BlockchainType.EVM_POS && BlockchainType.from(chain) != BlockchainType.EVM_POW) {
+        if (BlockchainType.from(chain) != BlockchainType.ETHEREUM) {
            return Mono.error(UnsupportedOperationException("Native subscribe is not supported for ${chain.chainCode}"))
        }

--- a/src/main/kotlin/io/emeraldpay/dshackle/startup/ConfiguredUpstreams.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/startup/ConfiguredUpstreams.kt
@@ -20,9 +20,7 @@ import brave.grpc.GrpcTracing
 import com.google.common.annotations.VisibleForTesting
 import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.BlockchainType.BITCOIN
-import io.emeraldpay.dshackle.BlockchainType.EVM_POS
-import io.emeraldpay.dshackle.BlockchainType.EVM_POW
-import io.emeraldpay.dshackle.BlockchainType.STARKNET
+import io.emeraldpay.dshackle.BlockchainType.ETHEREUM
 import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.Defaults
 import io.emeraldpay.dshackle.FileResolver
@@ -52,13 +50,12 @@ import io.emeraldpay.dshackle.upstream.bitcoin.ExtractBlock
 import io.emeraldpay.dshackle.upstream.bitcoin.ZMQServer
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.dshackle.upstream.calls.ManagedCallMethods
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumBlockValidator
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumLikeRpcUpstream
 import io.emeraldpay.dshackle.upstream.ethereum.WsConnectionFactory
 import io.emeraldpay.dshackle.upstream.ethereum.WsConnectionPoolFactory
 import io.emeraldpay.dshackle.upstream.forkchoice.ForkChoice
 import io.emeraldpay.dshackle.upstream.forkchoice.MostWorkForkChoice
 import io.emeraldpay.dshackle.upstream.forkchoice.NoChoiceWithPriorityForkChoice
+import io.emeraldpay.dshackle.upstream.generic.ChainSpecificRegistry
 import io.emeraldpay.dshackle.upstream.generic.GenericUpstream
 import io.emeraldpay.dshackle.upstream.generic.connectors.GenericConnectorFactory
 import io.emeraldpay.dshackle.upstream.generic.connectors.GenericConnectorFactory.ConnectorMode.RPC_REQUESTS_WITH_MIXED_HEAD
@@ -75,6 +72,7 @@ import org.springframework.context.ApplicationEventPublisher
 import org.springframework.stereotype.Component
 import reactor.core.scheduler.Scheduler
 import reactor.core.scheduler.Schedulers
+import java.lang.IllegalStateException
 import java.net.URI
 import java.util.concurrent.Executor
 import java.util.concurrent.Executors
@@ -138,24 +136,6 @@ open class ConfiguredUpstreams(
                    .merge(up.options ?: ChainOptions.PartialOptions())
                    .buildOptions()
                val upstream = when (BlockchainType.from(chain)) {
-                    EVM_POS -> {
-                        buildEthereumPosUpstream(
-                            up.nodeId,
-                            up.cast(EthereumPosConnection::class.java),
-                            chain,
-                            options,
-                            chainConfig,
-                        )
-                    }
-                    EVM_POW -> {
-                        buildEthereumUpstream(
-                            up.nodeId,
-                            up.cast(RpcConnection::class.java),
-                            chain,
-                            options,
-                            chainConfig,
-                        )
-                    }
                    BITCOIN -> {
                        buildBitcoinUpstream(
                            up.cast(BitcoinConnection::class.java),
@@ -165,13 +145,29 @@ open class ConfiguredUpstreams(
                        )
                    }

-                    STARKNET -> {
-                        buildStarknetUpstream(
+                    ETHEREUM -> {
+                        val posConn = up.cast(EthereumPosConnection::class.java)
+
+                        buildGenericUpstream(
                            up.nodeId,
-                            up.cast(RpcConnection::class.java),
+                            up,
+                            posConn.connection?.execution ?: throw IllegalStateException("Empty execution config"),
                            chain,
                            options,
                            chainConfig,
+                            posConn.connection?.upstreamRating ?: 0,
+                        )
+                    }
+
+                    else -> {
+                        buildGenericUpstream(
+                            up.nodeId,
+                            up,
+                            up.connection as RpcConnection,
+                            chain,
+                            options,
+                            chainConfig,
+                            0,
                        )
                    }
                }
@@ -224,31 +220,30 @@ open class ConfiguredUpstreams(
        }
    }

-    private fun buildStarknetUpstream(
+    private fun buildGenericUpstream(
        nodeId: Int?,
-        config: UpstreamsConfig.Upstream<RpcConnection>,
+        config: UpstreamsConfig.Upstream<*>,
+        connection: RpcConnection,
        chain: Chain,
        options: Options,
        chainConfig: ChainConfig,
+        nodeRating: Int,
    ): Upstream? {
        if (config.connection == null) {
            log.warn("Upstream doesn't have connection configuration")
            return null
        }

-        val connection = config.connection!!
+        val cs = ChainSpecificRegistry.resolve(chain)

        val connectorFactory = buildConnectorFactory(
            config.id!!,
            connection,
            chain,
-            NoChoiceWithPriorityForkChoice(0, config.id!!),
+            NoChoiceWithPriorityForkChoice(nodeRating, config.id!!),
            BlockValidator.ALWAYS_VALID,
            chainConfig,
-        )
-        if (connectorFactory == null) {
-            return null
-        }
+        ) ?: return null

        val methods = buildMethods(config, chain)

@@ -268,6 +263,9 @@ open class ConfiguredUpstreams(
            chainConfig,
            connectorFactory,
            eventPublisher,
+            cs::validator,
+            cs::labelDetector,
+            cs::subscriptionTopics,
        )

        upstream.start()
@@ -278,58 +276,6 @@ open class ConfiguredUpstreams(
        return upstream
    }

-    private fun buildEthereumPosUpstream(
-        nodeId: Int?,
-        config: UpstreamsConfig.Upstream<EthereumPosConnection>,
-        chain: Chain,
-        options: Options,
-        chainConf: ChainConfig,
-    ): Upstream? {
-        val conn = config.connection!!
-        val execution = conn.execution
-        if (execution == null) {
-            log.warn("Upstream doesn't have execution layer configuration")
-            return null
-        }
-        val urls = ArrayList<URI>()
-        val connectorFactory = buildConnectorFactory(
-            config.id!!,
-            execution,
-            chain,
-            NoChoiceWithPriorityForkChoice(conn.upstreamRating, config.id!!),
-            BlockValidator.ALWAYS_VALID,
-            chainConf,
-        )
-        val methods = buildMethods(config, chain)
-        if (connectorFactory == null) {
-            return null
-        }
-
-        val hashUrl = conn.execution!!.let {
-            if (it.connectorMode == RPC_REQUESTS_WITH_MIXED_HEAD.name) it.rpc?.url ?: it.ws?.url else it.ws?.url ?: it.rpc?.url
-        }
-        val hash = getHash(nodeId, hashUrl!!)
-        val upstream = EthereumLikeRpcUpstream(
-            config.id!!,
-            hash,
-            chain,
-            options,
-            config.role,
-            methods,
-            QuorumForLabels.QuorumItem(1, UpstreamsConfig.Labels.fromMap(config.labels)),
-            connectorFactory,
-            chainConf,
-            true,
-            eventPublisher,
-        )
-        upstream.start()
-        if (!upstream.isRunning) {
-            log.debug("Upstream ${upstream.getId()} is not running, it can't be added")
-            return null
-        }
-        return upstream
-    }
-
    private fun buildBitcoinUpstream(
        config: UpstreamsConfig.Upstream<BitcoinConnection>,
        chain: Chain,
@@ -373,45 +319,6 @@ open class ConfiguredUpstreams(
        return upstream
    }

-    private fun buildEthereumUpstream(
-        nodeId: Int?,
-        config: UpstreamsConfig.Upstream<RpcConnection>,
-        chain: Chain,
-        options: Options,
-        chainConf: ChainConfig,
-    ): Upstream? {
-        val conn = config.connection!!
-        val methods = buildMethods(config, chain)
-
-        val connectorFactory = buildConnectorFactory(
-            config.id!!,
-            conn,
-            chain,
-            MostWorkForkChoice(),
-            EthereumBlockValidator(),
-            chainConf,
-        )
-        if (connectorFactory == null) {
-            return null
-        }
-
-        val hashUrl = if (conn.connectorMode == RPC_REQUESTS_WITH_MIXED_HEAD.name) conn.rpc?.url ?: conn.ws?.url else conn.ws?.url ?: conn.rpc?.url
-        val upstream = EthereumLikeRpcUpstream(
-            config.id!!,
-            getHash(nodeId, hashUrl!!),
-            chain,
-            options, config.role,
-            methods,
-            QuorumForLabels.QuorumItem(1, UpstreamsConfig.Labels.fromMap(config.labels)),
-            connectorFactory,
-            chainConf,
-            false,
-            eventPublisher,
-        )
-        upstream.start()
-        return upstream
-    }
-
    private fun buildGrpcUpstream(
        nodeId: Int?,
        config: UpstreamsConfig.Upstream<UpstreamsConfig.GrpcConnection>,
@@ -460,13 +367,13 @@ open class ConfiguredUpstreams(

    private fun buildHttpFactory(conn: HttpEndpoint?, urls: ArrayList<URI>? = null): HttpRpcFactory? {
        return conn?.let { endpoint ->
-            val tls = conn?.tls?.let { tls ->
+            val tls = conn.tls?.let { tls ->
                tls.ca?.let { ca ->
                    fileResolver.resolve(ca).readBytes()
                }
            }
            urls?.add(endpoint.url)
-            HttpRpcFactory(endpoint.url.toString(), conn?.basicAuth, tls)
+            HttpRpcFactory(endpoint.url.toString(), conn.basicAuth, tls)
        }
    }

--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/AbstractChainFees.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/AbstractChainFees.kt
@@ -1,131 +0,0 @@
-package io.emeraldpay.dshackle.upstream
-
-import com.github.benmanes.caffeine.cache.Caffeine
-import io.emeraldpay.api.proto.BlockchainOuterClass
-import org.slf4j.LoggerFactory
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import java.time.Duration
-import java.util.EnumMap
-import java.util.function.Function
-
-abstract class AbstractChainFees<F, B, TR, T>(
-    private val heightLimit: Int,
-    private val upstreams: Multistream,
-    extractTx: (B) -> List<TR>?,
-) : ChainFees {
-
-    companion object {
-        private val log = LoggerFactory.getLogger(AbstractChainFees::class.java)
-    }
-
-    private val txSource = EnumMap<ChainFees.Mode, TxAt<B, TR>>(ChainFees.Mode::class.java)
-
-    init {
-        txSource[ChainFees.Mode.AVG_TOP] = TxAtTop(extractTx)
-        txSource[ChainFees.Mode.MIN_ALWAYS] = TxAtBottom(extractTx)
-        txSource[ChainFees.Mode.AVG_MIDDLE] = TxAtMiddle(extractTx)
-        txSource[ChainFees.Mode.AVG_LAST] = TxAtBottom(extractTx)
-        txSource[ChainFees.Mode.AVG_T5] = TxAtPos(extractTx, 5)
-        txSource[ChainFees.Mode.AVG_T20] = TxAtPos(extractTx, 20)
-        txSource[ChainFees.Mode.AVG_T50] = TxAtPos(extractTx, 50)
-    }
-
-    override fun estimate(mode: ChainFees.Mode, blocks: Int): Mono<BlockchainOuterClass.EstimateFeeResponse> {
-        return usingBlocks(blocks)
-            .flatMap { readFeesAt(it, mode) }
-            .transform(feeAggregation(mode))
-            .next()
-            .map(getResponseBuilder())
-    }
-
-    // ---
-
-    private val feeCache = Caffeine.newBuilder()
-        .expireAfterWrite(Duration.ofMinutes(60))
-        .build<Pair<Long, ChainFees.Mode>, F>()
-
-    fun usingBlocks(exp: Int): Flux<Long> {
-        val useBlocks = exp.coerceAtMost(heightLimit).coerceAtLeast(1)
-
-        val height = upstreams.getHead().getCurrentHeight()
-            ?: return Mono.fromCallable { log.warn("Upstream is not ready. No current height") }.thenMany(Mono.empty()) // TODO or throw an exception to build a gRPC error?
-        val startBlock: Int = height.toInt() - useBlocks + 1
-        if (startBlock < 0) {
-            log.warn("Blockchain doesn't have enough blocks. Height: $height")
-            return Flux.empty()
-        }
-
-        return Flux.range(startBlock, useBlocks).map { it.toLong() }
-    }
-
-    fun readFeesAt(height: Long, mode: ChainFees.Mode): Mono<F> {
-        val current = feeCache.getIfPresent(Pair(height, mode))
-        if (current != null) {
-            return Mono.just(current)
-        }
-        val txSelector = txSourceFor(mode)
-        return readFeesAt(height, txSelector).doOnNext {
-            // TODO it may be EMPTY for some blocks (ex. a no tx block), so nothing gets cached and goes to do the same call each time. so do cache empty values to avoid useless requests
-            feeCache.put(Pair(height, mode), it!!)
-        }
-    }
-
-    open fun txSourceFor(mode: ChainFees.Mode): TxAt<B, TR> {
-        return txSource[mode] ?: throw IllegalStateException("No TS Source for mode $mode")
-    }
-
-    abstract fun readFeesAt(height: Long, selector: TxAt<B, TR>): Mono<F>
-    abstract fun feeAggregation(mode: ChainFees.Mode): Function<Flux<F>, Mono<F>>
-    abstract fun getResponseBuilder(): Function<F, BlockchainOuterClass.EstimateFeeResponse>
-
-    abstract class TxAt<B, TR>(private val extractTx: Function<B, List<TR>?>) {
-        fun get(block: B): TR? {
-            val txes = extractTx.apply(block) ?: return null
-            return get(txes)
-        }
-
-        abstract fun get(transactions: List<TR>): TR?
-    }
-
-    class TxAtPos<B, TR>(extractTx: Function<B, List<TR>?>, private val pos: Int) : TxAt<B, TR>(extractTx) {
-
-        override fun get(transactions: List<TR>): TR? {
-            val index = pos.coerceAtMost(transactions.size - 1)
-            if (index < 0) {
-                return null
-            }
-            return transactions[transactions.size - index - 1]
-        }
-    }
-
-    class TxAtTop<B, TR>(extractTx: Function<B, List<TR>?>) : TxAt<B, TR>(extractTx) {
-        override fun get(transactions: List<TR>): TR? {
-            if (transactions.isEmpty()) {
-                return null
-            }
-            return transactions[0]
-        }
-    }
-
-    class TxAtBottom<B, TR>(extractTx: Function<B, List<TR>?>) : TxAt<B, TR>(extractTx) {
-        override fun get(transactions: List<TR>): TR? {
-            if (transactions.isEmpty()) {
-                return null
-            }
-            return transactions.last()
-        }
-    }
-
-    class TxAtMiddle<B, TR>(extractTx: Function<B, List<TR>?>) : TxAt<B, TR>(extractTx) {
-        override fun get(transactions: List<TR>): TR? {
-            if (transactions.isEmpty()) {
-                return null
-            }
-            if (transactions.size == 1) {
-                return transactions[0]
-            }
-            return transactions[transactions.size / 2]
-        }
-    }
-}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/CachingReader.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/CachingReader.kt
@@ -1,3 +1,15 @@
 package io.emeraldpay.dshackle.upstream

-interface CachingReader
+interface CachingReader : Lifecycle
+
+object NoopCachingReader : CachingReader {
+    override fun start() {
+    }
+
+    override fun stop() {
+    }
+
+    override fun isRunning(): Boolean {
+        return true
+    }
+}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/CallTargetsHolder.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/CallTargetsHolder.kt
@@ -18,9 +18,8 @@ class CallTargetsHolder {

    private fun setupDefaultMethods(chain: Chain): CallMethods {
        val created = when (BlockchainType.from(chain)) {
-            BlockchainType.EVM_POW -> DefaultEthereumMethods(chain)
            BlockchainType.BITCOIN -> DefaultBitcoinMethods()
-            BlockchainType.EVM_POS -> DefaultEthereumMethods(chain)
+            BlockchainType.ETHEREUM -> DefaultEthereumMethods(chain)
            BlockchainType.STARKNET -> DefaultStarknetMethods(chain)
        }
        callTargets[chain] = created
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ChainFees.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ChainFees.kt
@@ -1,35 +0,0 @@
-package io.emeraldpay.dshackle.upstream
-
-import io.emeraldpay.api.proto.BlockchainOuterClass
-import reactor.core.publisher.Mono
-
-interface ChainFees {
-
-    companion object {
-        fun extractMode(req: BlockchainOuterClass.EstimateFeeRequest): Mode? {
-            return when (req.mode!!) {
-                BlockchainOuterClass.FeeEstimationMode.INVALID -> null
-                BlockchainOuterClass.FeeEstimationMode.AVG_LAST -> Mode.AVG_LAST
-                BlockchainOuterClass.FeeEstimationMode.AVG_T5 -> Mode.AVG_T5
-                BlockchainOuterClass.FeeEstimationMode.AVG_T20 -> Mode.AVG_T20
-                BlockchainOuterClass.FeeEstimationMode.AVG_T50 -> Mode.AVG_T50
-                BlockchainOuterClass.FeeEstimationMode.MIN_ALWAYS -> Mode.MIN_ALWAYS
-                BlockchainOuterClass.FeeEstimationMode.AVG_MIDDLE -> Mode.AVG_MIDDLE
-                BlockchainOuterClass.FeeEstimationMode.AVG_TOP -> Mode.AVG_TOP
-                BlockchainOuterClass.FeeEstimationMode.UNRECOGNIZED -> null
-            }
-        }
-    }
-
-    fun estimate(mode: Mode, blocks: Int): Mono<BlockchainOuterClass.EstimateFeeResponse>
-
-    enum class Mode {
-        AVG_LAST,
-        AVG_T5,
-        AVG_T20,
-        AVG_T50,
-        MIN_ALWAYS,
-        AVG_MIDDLE,
-        AVG_TOP,
-    }
-}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/EgressSubscription.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/EgressSubscription.kt
@@ -22,7 +22,7 @@ interface EgressSubscription {
    fun subscribe(topic: String, params: Any?, matcher: Selector.Matcher): Flux<out Any>
 }

-class EmptyEgressSubscription : EgressSubscription {
+object EmptyEgressSubscription : EgressSubscription {
    override fun getAvailableTopics(): List<String> {
        return emptyList()
    }
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/LabelsDetector.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/LabelsDetector.kt
@@ -0,0 +1,10 @@
+package io.emeraldpay.dshackle.upstream
+
+import io.emeraldpay.dshackle.Chain
+import io.emeraldpay.dshackle.reader.JsonRpcReader
+import reactor.core.publisher.Flux
+
+typealias LabelsDetectorBuilder = (Chain, JsonRpcReader) -> LabelsDetector?
+interface LabelsDetector {
+    fun detectLabels(): Flux<Pair<String, String>>
+}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/Multistream.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/Multistream.kt
@@ -51,10 +51,12 @@ import kotlin.concurrent.withLock
 */
 abstract class Multistream(
    val chain: Chain,
-    private val upstreams: MutableList<Upstream>,
    val caches: Caches,
 ) : Upstream, Lifecycle, HasEgressSubscription {

+    abstract fun getUpstreams(): MutableList<out Upstream>
+    abstract fun addUpstreamInternal(u: Upstream)
+
    companion object {
        private const val metrics = "upstreams"
    }
@@ -93,30 +95,6 @@ abstract class Multistream(
        .multicast()
        .directBestEffort<Upstream>()

-    init {
-        UpstreamAvailability.values().forEach { status ->
-            Metrics.gauge(
-                "$metrics.availability",
-                listOf(Tag.of("chain", chain.chainCode), Tag.of("status", status.name.lowercase())),
-                this,
-            ) {
-                upstreams.count { it.getStatus() == status }.toDouble()
-            }
-        }
-
-        Metrics.gauge(
-            "$metrics.connected",
-            listOf(Tag.of("chain", chain.chainCode)),
-            this,
-        ) {
-            upstreams.size.toDouble()
-        }
-
-        upstreams.forEach { up ->
-            monitorUpstream(up)
-        }
-    }
-
    override fun getSubscriptionTopics(): List<String> {
        return getEgressSubscription().getAvailableTopics()
    }
@@ -153,29 +131,49 @@ abstract class Multistream(
        onUpstreamsUpdated()
    }

+    init {
+        UpstreamAvailability.entries.forEach { status ->
+            Metrics.gauge(
+                "$metrics.availability",
+                listOf(Tag.of("chain", chain.chainCode), Tag.of("status", status.name.lowercase())),
+                this,
+            ) {
+                getAll().count { it.getStatus() == status }.toDouble()
+            }
+        }
+
+        Metrics.gauge(
+            "$metrics.connected",
+            listOf(Tag.of("chain", chain.chainCode)),
+            this,
+        ) {
+            getAll().size.toDouble()
+        }
+    }
+
    /**
     * Get list of all underlying upstreams
     */
    open fun getAll(): List<Upstream> {
-        return upstreams
+        return getUpstreams()
    }

    /**
     * Add an upstream
     */
    fun addUpstream(upstream: Upstream): Boolean =
-        upstreams.none {
+        getUpstreams().none {
            it.getId() == upstream.getId()
        }.also {
            if (it) {
-                upstreams.add(upstream)
+                addUpstreamInternal(upstream)
                addHead(upstream)
                monitorUpstream(upstream)
            }
        }

    fun removeUpstream(id: String): Boolean =
-        upstreams.removeIf { up ->
+        getUpstreams().removeIf { up ->
            (up.getId() == id).also {
                if (it) {
                    up.stop()
@@ -196,13 +194,13 @@ abstract class Multistream(
        if (seq >= Int.MAX_VALUE / 2) {
            seq = 0
        }
-        return FilteredApis(chain, upstreams, matcher, i)
+        return FilteredApis(chain, getUpstreams(), matcher, i)
    }

    /**
     * Finds an API that leverages caches and other optimizations/transformations of the request.
     */
-    abstract fun getLocalReader(localEnabled: Boolean): Mono<JsonRpcReader>
+    abstract fun getLocalReader(): Mono<JsonRpcReader>

    override fun getIngressReader(): JsonRpcReader {
        throw NotImplementedError("Immediate direct API is not implemented for Aggregated Upstream")
@@ -235,6 +233,7 @@ abstract class Multistream(
                    lagObserver = null
                    upstreams[0].setLag(0)
                }
+
                upstreams.size > 1 -> if (lagObserver == null) lagObserver = makeLagObserver()
            }
        }
@@ -389,17 +388,17 @@ abstract class Multistream(
        } catch (e: Exception) {
            log.warn("Head processing error: ${e.javaClass} ${e.message}")
        }
-        val statuses = upstreams.asSequence().map { it.getStatus() }
+        val statuses = getUpstreams().asSequence().map { it.getStatus() }
            .groupBy { it }
            .map { "${it.key.name}/${it.value.size}" }
            .joinToString(",")
-        val lag = upstreams.joinToString(", ") {
+        val lag = getUpstreams().joinToString(", ") {
            // by default, when no lag is available it uses Long.MAX_VALUE, and it doesn't make sense to print
            // status with such value. use NA (as Not Available) instead
            val value = it.getLag()
            value?.toString() ?: "NA"
        }
-        val weak = upstreams
+        val weak = getUpstreams()
            .filter { it.getStatus() != UpstreamAvailability.OK }
            .joinToString(", ") { it.getId() }

@@ -424,6 +423,7 @@ abstract class Multistream(
                        onUpstreamsUpdated()
                        updateUpstreams.emitNext(event.upstream) { _, res -> res == Sinks.EmitResult.FAIL_NON_SERIALIZED }
                    }
+
                    UpstreamChangeEvent.ChangeType.ADDED -> {
                        if (!started) {
                            start()
@@ -441,6 +441,7 @@ abstract class Multistream(
                            }
                        }
                    }
+
                    UpstreamChangeEvent.ChangeType.REMOVED -> {
                        removeUpstream(event.upstream.getId()).takeIf { it }?.let {
                            try {
@@ -458,10 +459,10 @@ abstract class Multistream(
    }

    fun haveUpstreams(): Boolean =
-        upstreams.isNotEmpty()
+        getUpstreams().isNotEmpty()

    fun hasMatchingUpstream(matcher: Selector.LabelSelectorMatcher): Boolean {
-        return upstreams.any { matcher.matches(it) }
+        return getUpstreams().any { matcher.matches(it) }
    }

    fun subscribeAddedUpstreams(): Flux<Upstream> =
@@ -469,12 +470,16 @@ abstract class Multistream(

    fun subscribeRemovedUpstreams(): Flux<Upstream> =
        removedUpstreams.asFlux()
+
    fun subscribeUpdatedUpstreams(): Flux<Upstream> =
        updateUpstreams.asFlux()

    abstract fun makeLagObserver(): HeadLagObserver

-    open fun tryProxySubscribe(matcher: Selector.Matcher, request: BlockchainOuterClass.NativeSubscribeRequest): Flux<out Any>? = null
+    open fun tryProxySubscribe(
+        matcher: Selector.Matcher,
+        request: BlockchainOuterClass.NativeSubscribeRequest,
+    ): Flux<out Any>? = null

    abstract fun getCachingReader(): CachingReader?

--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/UpstreamValidator.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/UpstreamValidator.kt
@@ -0,0 +1,25 @@
+package io.emeraldpay.dshackle.upstream
+
+import io.emeraldpay.dshackle.Chain
+import io.emeraldpay.dshackle.config.ChainsConfig.ChainConfig
+import io.emeraldpay.dshackle.foundation.ChainOptions
+import reactor.core.publisher.Flux
+import reactor.core.publisher.Mono
+
+typealias UpstreamValidatorBuilder = (Chain, Upstream, ChainOptions.Options, ChainConfig) -> UpstreamValidator?
+
+interface UpstreamValidator {
+    fun start(): Flux<UpstreamAvailability>
+
+    fun validateUpstreamSettings(): Mono<ValidateUpstreamSettingsResult>
+
+    fun validateUpstreamSettingsOnStartup(): ValidateUpstreamSettingsResult {
+        return validateUpstreamSettings().block() ?: ValidateUpstreamSettingsResult.UPSTREAM_FATAL_SETTINGS_ERROR
+    }
+}
+
+enum class ValidateUpstreamSettingsResult {
+    UPSTREAM_VALID,
+    UPSTREAM_SETTINGS_ERROR,
+    UPSTREAM_FATAL_SETTINGS_ERROR,
+}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/BitcoinMultistream.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/BitcoinMultistream.kt
@@ -43,7 +43,7 @@ open class BitcoinMultistream(
    private val sourceUpstreams: MutableList<BitcoinUpstream>,
    caches: Caches,
    private val headScheduler: Scheduler,
-) : Multistream(chain, sourceUpstreams as MutableList<Upstream>, caches), Lifecycle {
+) : Multistream(chain, caches), Lifecycle {

    private var head: Head = EmptyHead()
    private var esplora = sourceUpstreams.find { it.esploraClient != null }?.esploraClient
@@ -51,6 +51,13 @@ open class BitcoinMultistream(
    private var addressActiveCheck: AddressActiveCheck? = null
    private var xpubAddresses: XpubAddresses? = null
    private var callRouter: LocalCallRouter = LocalCallRouter(DefaultBitcoinMethods(), reader)
+    override fun getUpstreams(): MutableList<out Upstream> {
+        return sourceUpstreams
+    }
+
+    override fun addUpstreamInternal(u: Upstream) {
+        sourceUpstreams.add(u as BitcoinUpstream)
+    }

    override fun init() {
        if (sourceUpstreams.size > 0) {
@@ -59,11 +66,6 @@ open class BitcoinMultistream(
        super.init()
    }

-    open val upstreams: List<BitcoinUpstream>
-        get() {
-            return sourceUpstreams
-        }
-
    open fun getXpubAddresses(): XpubAddresses? {
        return xpubAddresses
    }
@@ -103,7 +105,7 @@ open class BitcoinMultistream(
            .switchIfEmpty(Mono.error(Exception("No API available for $chain")))
    }

-    override fun getLocalReader(localEnabled: Boolean): Mono<JsonRpcReader> {
+    override fun getLocalReader(): Mono<JsonRpcReader> {
        return Mono.just(callRouter)
    }

@@ -146,7 +148,7 @@ open class BitcoinMultistream(
    }

    override fun getEgressSubscription(): EgressSubscription {
-        return EmptyEgressSubscription()
+        return EmptyEgressSubscription
    }

    override fun isRunning(): Boolean {
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/BitcoinReader.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/bitcoin/BitcoinReader.kt
@@ -44,7 +44,7 @@ open class BitcoinReader(

    private val unspentReader: UnspentReader = if (esploraClient != null) {
        EsploraUnspentReader(esploraClient, head)
-    } else if (upstreams.upstreams.any { it.isGrpc() && it.getCapabilities().contains(Capability.BALANCE) }) {
+    } else if (upstreams.getUpstreams().any { it.isGrpc() && it.getCapabilities().contains(Capability.BALANCE) }) {
        RemoteUnspentReader(upstreams)
    } else {
        RpcUnspentReader(upstreams)
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/ERC20Balance.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/ERC20Balance.kt
@@ -1,75 +0,0 @@
-/**
- * Copyright (c) 2021 EmeraldPay, Inc
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import io.emeraldpay.dshackle.upstream.ApiSource
-import io.emeraldpay.dshackle.upstream.Head
-import io.emeraldpay.dshackle.upstream.Selector
-import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
-import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
-import io.emeraldpay.etherjar.domain.Address
-import io.emeraldpay.etherjar.erc20.ERC20Token
-import io.emeraldpay.etherjar.hex.Hex32
-import io.emeraldpay.etherjar.hex.HexQuantity
-import org.slf4j.LoggerFactory
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import java.math.BigInteger
-
-/**
- * Query for a ERC20 token balance for an address
- */
-open class ERC20Balance {
-
-    companion object {
-        private val log = LoggerFactory.getLogger(ERC20Balance::class.java)
-    }
-
-    open fun getBalance(upstreams: EthereumPosMultiStream, token: ERC20Token, address: Address): Mono<BigInteger> {
-        return upstreams
-            // use only up-to-date upstreams
-            .getApiSource(Selector.HeightMatcher(upstreams.getHead().getCurrentHeight() ?: 0))
-            .let { getBalance(it, token, address) }
-    }
-
-    open fun getBalance(apis: ApiSource, token: ERC20Token, address: Address): Mono<BigInteger> {
-        apis.request(1)
-        return Flux.from(apis)
-            .flatMap {
-                getBalance(it.cast(EthereumLikeRpcUpstream::class.java), token, address)
-            }
-            .doOnNext {
-                apis.resolve()
-            }
-            .next()
-    }
-
-    open fun getBalance(upstream: EthereumLikeRpcUpstream, token: ERC20Token, address: Address): Mono<BigInteger> {
-        return upstream
-            .getIngressReader()
-            .read(prepareEthCall(token, address, upstream.getHead()))
-            .flatMap(JsonRpcResponse::requireStringResult)
-            .map { Hex32.from(it).asQuantity().value }
-    }
-
-    fun prepareEthCall(token: ERC20Token, target: Address, head: Head): JsonRpcRequest {
-        val call = token
-            .readBalanceOf(target)
-            .toJson()
-        val height = head.getCurrentHeight()?.let { HexQuantity.from(it).toHex() } ?: "latest"
-        return JsonRpcRequest("eth_call", listOf(call, height))
-    }
-}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumCachingReader.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumCachingReader.kt
@@ -34,7 +34,6 @@ import io.emeraldpay.dshackle.reader.RekeyingReader
 import io.emeraldpay.dshackle.reader.SpannedReader
 import io.emeraldpay.dshackle.reader.TransformingReader
 import io.emeraldpay.dshackle.upstream.CachingReader
-import io.emeraldpay.dshackle.upstream.Lifecycle
 import io.emeraldpay.dshackle.upstream.Multistream
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumDirectReader.Result
@@ -58,7 +57,7 @@ open class EthereumCachingReader(
    private val caches: Caches,
    callMethodsFactory: Factory<CallMethods>,
    private val tracer: Tracer,
-) : Lifecycle, CachingReader {
+) : CachingReader {

    private val objectMapper: ObjectMapper = Global.objectMapper
    private val balanceCache = CurrentBlockCache<Address, Wei>()
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumChainSpecific.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumChainSpecific.kt
@@ -1,9 +1,31 @@
 package io.emeraldpay.dshackle.upstream.ethereum

+import io.emeraldpay.dshackle.Chain
+import io.emeraldpay.dshackle.config.ChainsConfig.ChainConfig
 import io.emeraldpay.dshackle.data.BlockContainer
+import io.emeraldpay.dshackle.foundation.ChainOptions.Options
+import io.emeraldpay.dshackle.reader.JsonRpcReader
+import io.emeraldpay.dshackle.upstream.CachingReader
+import io.emeraldpay.dshackle.upstream.Capability
+import io.emeraldpay.dshackle.upstream.EgressSubscription
+import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.LabelsDetector
+import io.emeraldpay.dshackle.upstream.Multistream
+import io.emeraldpay.dshackle.upstream.Upstream
+import io.emeraldpay.dshackle.upstream.UpstreamValidator
+import io.emeraldpay.dshackle.upstream.calls.CallMethods
+import io.emeraldpay.dshackle.upstream.ethereum.subscribe.AggregatedPendingTxes
+import io.emeraldpay.dshackle.upstream.ethereum.subscribe.EthereumLabelsDetector
+import io.emeraldpay.dshackle.upstream.ethereum.subscribe.NoPendingTxes
+import io.emeraldpay.dshackle.upstream.ethereum.subscribe.PendingTxesSource
+import io.emeraldpay.dshackle.upstream.generic.CachingReaderBuilder
 import io.emeraldpay.dshackle.upstream.generic.ChainSpecific
+import io.emeraldpay.dshackle.upstream.generic.GenericUpstream
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import org.springframework.cloud.sleuth.Tracer
+import reactor.core.publisher.Mono
+import reactor.core.scheduler.Scheduler

 object EthereumChainSpecific : ChainSpecific {
    override fun parseBlock(data: JsonRpcResponse, upstreamId: String): BlockContainer {
@@ -11,4 +33,57 @@ object EthereumChainSpecific : ChainSpecific {
    }

    override fun latestBlockRequest() = JsonRpcRequest("eth_getBlockByNumber", listOf("latest", false))
+    override fun localReaderBuilder(
+        cachingReader: CachingReader,
+        methods: CallMethods,
+        head: Head,
+    ): Mono<JsonRpcReader> {
+        return Mono.just(EthereumLocalReader(cachingReader as EthereumCachingReader, methods, head))
+    }
+
+    override fun subscriptionBuilder(headScheduler: Scheduler): (Multistream) -> EgressSubscription {
+        return { ms ->
+            val pendingTxes: PendingTxesSource = (ms.getAll())
+                .filter { it is GenericUpstream }
+                .map { it as GenericUpstream }
+                .mapNotNull {
+                    (it.getIngressSubscription() as EthereumIngressSubscription).getPendingTxes()
+                }.let {
+                    if (it.isEmpty()) {
+                        NoPendingTxes()
+                    } else if (it.size == 1) {
+                        it.first()
+                    } else {
+                        AggregatedPendingTxes(it)
+                    }
+                }
+            EthereumEgressSubscription(ms, headScheduler, pendingTxes)
+        }
+    }
+
+    override fun makeCachingReaderBuilder(tracer: Tracer): CachingReaderBuilder {
+        return { ms, caches, methodsFactory -> EthereumCachingReader(ms, caches, methodsFactory, tracer) }
+    }
+
+    override fun validator(
+        chain: Chain,
+        upstream: Upstream,
+        options: Options,
+        config: ChainConfig,
+    ): UpstreamValidator? {
+        return EthereumUpstreamValidator(chain, upstream, options, config)
+    }
+
+    override fun labelDetector(chain: Chain, reader: JsonRpcReader): LabelsDetector? {
+        return EthereumLabelsDetector(reader, chain)
+    }
+
+    override fun subscriptionTopics(upstream: GenericUpstream): List<String> {
+        val subs = if (upstream.getCapabilities().contains(Capability.WS_HEAD)) {
+            listOf(EthereumEgressSubscription.METHOD_NEW_HEADS, EthereumEgressSubscription.METHOD_LOGS)
+        } else {
+            listOf()
+        }
+        return upstream.getIngressSubscription().getAvailableTopics().plus(subs).toSet().toList()
+    }
 }
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumFees.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumFees.kt
@@ -1,87 +0,0 @@
-/**
- * Copyright (c) 2021 EmeraldPay, Inc
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import io.emeraldpay.dshackle.upstream.AbstractChainFees
-import io.emeraldpay.dshackle.upstream.ChainFees
-import io.emeraldpay.dshackle.upstream.Multistream
-import io.emeraldpay.dshackle.upstream.ethereum.json.BlockJson
-import io.emeraldpay.dshackle.upstream.ethereum.json.TransactionJsonSnapshot
-import io.emeraldpay.etherjar.domain.Wei
-import io.emeraldpay.etherjar.rpc.json.TransactionRefJson
-import org.slf4j.LoggerFactory
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import reactor.util.function.Tuples
-import java.util.function.Function
-
-abstract class EthereumFees(
-    upstreams: Multistream,
-    private val reader: EthereumCachingReader,
-    heightLimit: Int,
-) : AbstractChainFees<EthereumFees.EthereumFee, BlockJson<TransactionRefJson>, TransactionRefJson, TransactionJsonSnapshot>(heightLimit, upstreams, extractTx), ChainFees {
-
-    companion object {
-        private val log = LoggerFactory.getLogger(EthereumFees::class.java)
-
-        private val extractTx = { block: BlockJson<TransactionRefJson> ->
-            block.transactions
-        }
-    }
-
-    abstract fun extractFee(block: BlockJson<TransactionRefJson>, tx: TransactionJsonSnapshot): EthereumFee
-
-    override fun readFeesAt(height: Long, selector: TxAt<BlockJson<TransactionRefJson>, TransactionRefJson>): Mono<EthereumFee> {
-        return reader.blocksByHeightParsed().read(height)
-            .flatMap { block ->
-                Mono.justOrEmpty(selector.get(block))
-                    .cast(TransactionRefJson::class.java)
-                    .flatMap { reader.txByHash().read(it.hash) }
-                    .map { tx -> extractFee(block, tx) }
-            }
-    }
-
-    override fun feeAggregation(mode: ChainFees.Mode): Function<Flux<EthereumFee>, Mono<EthereumFee>> {
-        if (mode == ChainFees.Mode.MIN_ALWAYS) {
-            return Function { src ->
-                src.reduce { a, b ->
-                    EthereumFee(
-                        a.max.coerceAtLeast(b.max),
-                        a.priority.coerceAtLeast(b.priority),
-                        a.paid.coerceAtLeast(b.paid),
-                        Wei.ZERO,
-                    )
-                }
-            }
-        }
-        return Function { src ->
-            src.map { Tuples.of(1, it) }
-                .reduce { a, b ->
-                    Tuples.of(a.t1 + b.t1, a.t2.plus(b.t2))
-                }.map {
-                    EthereumFee(it.t2.max / it.t1, it.t2.priority / it.t1, it.t2.paid / it.t1, it.t2.base / it.t1)
-                }
-        }
-    }
-
-    // ---
-
-    data class EthereumFee(val max: Wei, val priority: Wei, val paid: Wei, val base: Wei) {
-        fun plus(o: EthereumFee): EthereumFee {
-            return EthereumFee(max + o.max, priority + o.priority, paid + o.paid, base + o.base)
-        }
-    }
-}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLegacyFees.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLegacyFees.kt
@@ -1,49 +0,0 @@
-/**
- * Copyright (c) 2021 EmeraldPay, Inc
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import io.emeraldpay.api.proto.BlockchainOuterClass
-import io.emeraldpay.dshackle.upstream.ethereum.json.BlockJson
-import io.emeraldpay.dshackle.upstream.ethereum.json.TransactionJsonSnapshot
-import io.emeraldpay.etherjar.domain.Wei
-import io.emeraldpay.etherjar.rpc.json.TransactionRefJson
-import org.slf4j.LoggerFactory
-import java.util.function.Function
-
-class EthereumLegacyFees(upstreams: EthereumMultistream, reader: EthereumCachingReader, heightLimit: Int) :
-    EthereumFees(upstreams, reader, heightLimit) {
-
-    companion object {
-        private val log = LoggerFactory.getLogger(EthereumLegacyFees::class.java)
-    }
-
-    private val toGrpc: Function<EthereumFee, BlockchainOuterClass.EstimateFeeResponse> = Function {
-        BlockchainOuterClass.EstimateFeeResponse.newBuilder()
-            .setEthereumStd(
-                BlockchainOuterClass.EthereumStdFees.newBuilder()
-                    .setFee(it.paid.amount.toString()),
-            )
-            .build()
-    }
-
-    override fun extractFee(block: BlockJson<TransactionRefJson>, tx: TransactionJsonSnapshot): EthereumFee {
-        return EthereumFee(tx.gasPrice, tx.gasPrice, tx.gasPrice, Wei.ZERO)
-    }
-
-    override fun getResponseBuilder(): Function<EthereumFee, BlockchainOuterClass.EstimateFeeResponse> {
-        return toGrpc
-    }
-}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLikeRpcUpstream.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLikeRpcUpstream.kt
@@ -1,206 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2019 ETCDEV GmbH
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import io.emeraldpay.dshackle.Chain
-import io.emeraldpay.dshackle.cache.Caches
-import io.emeraldpay.dshackle.cache.CachesEnabled
-import io.emeraldpay.dshackle.config.ChainsConfig
-import io.emeraldpay.dshackle.config.UpstreamsConfig
-import io.emeraldpay.dshackle.foundation.ChainOptions
-import io.emeraldpay.dshackle.reader.JsonRpcReader
-import io.emeraldpay.dshackle.startup.QuorumForLabels
-import io.emeraldpay.dshackle.startup.UpstreamChangeEvent
-import io.emeraldpay.dshackle.upstream.Capability
-import io.emeraldpay.dshackle.upstream.Head
-import io.emeraldpay.dshackle.upstream.Upstream
-import io.emeraldpay.dshackle.upstream.UpstreamAvailability
-import io.emeraldpay.dshackle.upstream.calls.CallMethods
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstreamValidator.ValidateUpstreamSettingsResult.UPSTREAM_FATAL_SETTINGS_ERROR
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstreamValidator.ValidateUpstreamSettingsResult.UPSTREAM_SETTINGS_ERROR
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstreamValidator.ValidateUpstreamSettingsResult.UPSTREAM_VALID
-import io.emeraldpay.dshackle.upstream.ethereum.subscribe.EthereumLabelsDetector
-import io.emeraldpay.dshackle.upstream.generic.connectors.ConnectorFactory
-import io.emeraldpay.dshackle.upstream.generic.connectors.GenericConnector
-import org.springframework.context.ApplicationEventPublisher
-import org.springframework.context.Lifecycle
-import reactor.core.Disposable
-import reactor.core.publisher.Flux
-import java.time.Duration
-import java.util.concurrent.atomic.AtomicBoolean
-
-open class EthereumLikeRpcUpstream(
-    id: String,
-    hash: Byte,
-    val chain: Chain,
-    options: ChainOptions.Options,
-    role: UpstreamsConfig.UpstreamRole,
-    targets: CallMethods?,
-    private val node: QuorumForLabels.QuorumItem?,
-    connectorFactory: ConnectorFactory,
-    chainConfig: ChainsConfig.ChainConfig,
-    skipEnhance: Boolean,
-    private val eventPublisher: ApplicationEventPublisher?,
-) : EthereumLikeUpstream(id, hash, options, role, targets, node, chainConfig), Lifecycle, Upstream, CachesEnabled {
-    private val validator: EthereumUpstreamValidator = EthereumUpstreamValidator(chain, this, getOptions(), chainConfig.callLimitContract)
-    protected val connector: GenericConnector = connectorFactory.create(this, chain, skipEnhance)
-    private val labelsDetector = EthereumLabelsDetector(this.getIngressReader(), chain)
-    private var hasLiveSubscriptionHead: AtomicBoolean = AtomicBoolean(false)
-
-    private var validatorSubscription: Disposable? = null
-    private var livenessSubscription: Disposable? = null
-    private var validationSettingsSubscription: Disposable? = null
-
-    override fun getCapabilities(): Set<Capability> {
-        return if (hasLiveSubscriptionHead.get()) {
-            setOf(Capability.RPC, Capability.BALANCE, Capability.WS_HEAD)
-        } else {
-            setOf(Capability.RPC, Capability.BALANCE)
-        }
-    }
-
-    override fun setCaches(caches: Caches) {
-        if (connector is CachesEnabled) {
-            connector.setCaches(caches)
-        }
-    }
-
-    override fun start() {
-        log.info("Configured for ${chain.chainName}")
-        connector.start()
-        val validSettingsResult = validator.validateUpstreamSettingsOnStartup()
-        when (validSettingsResult) {
-            UPSTREAM_FATAL_SETTINGS_ERROR -> {
-                connector.stop()
-                log.warn("Upstream ${getId()} couldn't start, invalid upstream settings")
-                return
-            }
-            UPSTREAM_SETTINGS_ERROR -> {
-                validateUpstreamSettings()
-            }
-            else -> {
-                upstreamStart()
-                labelsDetector.detectLabels()
-                    .toStream()
-                    .forEach { updateLabels(it) }
-            }
-        }
-    }
-
-    private fun validateUpstreamSettings() {
-        validationSettingsSubscription = Flux.interval(
-            Duration.ofSeconds(10),
-            Duration.ofSeconds(20),
-        ).flatMap {
-            validator.validateUpstreamSettings()
-        }.subscribe {
-            when (it) {
-                UPSTREAM_FATAL_SETTINGS_ERROR -> {
-                    connector.stop()
-                    log.warn("Upstream ${getId()} couldn't start, invalid upstream settings")
-                    disposeValidationSettingsSubscription()
-                }
-                UPSTREAM_VALID -> {
-                    upstreamStart()
-                    labelsDetector.detectLabels()
-                        .subscribe { label -> updateLabels(label) }
-                    eventPublisher?.publishEvent(UpstreamChangeEvent(chain, this, UpstreamChangeEvent.ChangeType.ADDED))
-                    disposeValidationSettingsSubscription()
-                }
-                else -> {
-                    log.warn("Continue validation of upstream ${getId()}")
-                }
-            }
-        }
-    }
-
-    private fun upstreamStart() {
-        if (getOptions().disableValidation) {
-            log.warn("Disable validation for upstream ${this.getId()}")
-            this.setLag(0)
-            this.setStatus(UpstreamAvailability.OK)
-        } else {
-            log.debug("Start validation for upstream ${this.getId()}")
-            validatorSubscription = validator.start()
-                .subscribe(this::setStatus)
-        }
-        livenessSubscription = connector.hasLiveSubscriptionHead().subscribe({
-            hasLiveSubscriptionHead.set(it)
-            eventPublisher?.publishEvent(UpstreamChangeEvent(chain, this, UpstreamChangeEvent.ChangeType.UPDATED))
-        }, {
-            log.debug("Error while checking live subscription for ${getId()}", it)
-        },)
-    }
-
-    private fun updateLabels(label: Pair<String, String>) {
-        log.info("Detected label ${label.first} with value ${label.second} for upstream ${getId()}")
-        node?.labels?.let { labels ->
-            labels[label.first] = label.second
-        }
-    }
-
-    override fun getIngressSubscription(): EthereumIngressSubscription {
-        return connector.getIngressSubscription()
-    }
-
-    override fun getSubscriptionTopics(): List<String> {
-        val subs = if (getCapabilities().contains(Capability.WS_HEAD)) {
-            listOf(EthereumEgressSubscription.METHOD_NEW_HEADS, EthereumEgressSubscription.METHOD_LOGS)
-        } else {
-            listOf()
-        }
-        return getIngressSubscription().getAvailableTopics().plus(subs).toSet().toList()
-    }
-
-    override fun getHead(): Head {
-        return connector.getHead()
-    }
-
-    override fun stop() {
-        validatorSubscription?.dispose()
-        validatorSubscription = null
-        livenessSubscription?.dispose()
-        livenessSubscription = null
-        disposeValidationSettingsSubscription()
-        connector.stop()
-    }
-
-    override fun isRunning(): Boolean {
-        return connector.isRunning() && validationSettingsSubscription == null
-    }
-
-    override fun getIngressReader(): JsonRpcReader {
-        return connector.getIngressReader()
-    }
-
-    override fun isGrpc(): Boolean {
-        return false
-    }
-
-    @Suppress("UNCHECKED_CAST")
-    override fun <T : Upstream> cast(selfType: Class<T>): T {
-        if (!selfType.isAssignableFrom(this.javaClass)) {
-            throw ClassCastException("Cannot cast ${this.javaClass} to $selfType")
-        }
-        return this as T
-    }
-
-    private fun disposeValidationSettingsSubscription() {
-        validationSettingsSubscription?.dispose()
-        validationSettingsSubscription = null
-    }
-}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLikeUpstream.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLikeUpstream.kt
@@ -1,48 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2019 ETCDEV GmbH
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import io.emeraldpay.dshackle.config.ChainsConfig
-import io.emeraldpay.dshackle.config.UpstreamsConfig
-import io.emeraldpay.dshackle.foundation.ChainOptions
-import io.emeraldpay.dshackle.startup.QuorumForLabels
-import io.emeraldpay.dshackle.upstream.Capability
-import io.emeraldpay.dshackle.upstream.DefaultUpstream
-import io.emeraldpay.dshackle.upstream.calls.CallMethods
-
-abstract class EthereumLikeUpstream(
-    id: String,
-    hash: Byte,
-    options: ChainOptions.Options,
-    role: UpstreamsConfig.UpstreamRole,
-    targets: CallMethods?,
-    private val node: QuorumForLabels.QuorumItem?,
-    val chainConfig: ChainsConfig.ChainConfig,
-) : DefaultUpstream(id, hash, options, role, targets, node, chainConfig) {
-
-    private val capabilities = setOf(Capability.RPC, Capability.BALANCE)
-
-    override fun getCapabilities(): Set<Capability> {
-        return capabilities
-    }
-
-    override fun getLabels(): Collection<UpstreamsConfig.Labels> {
-        return node?.let { listOf(it.labels) } ?: emptyList()
-    }
-
-    abstract fun getIngressSubscription(): EthereumIngressSubscription
-}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLocalReader.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumLocalReader.kt
@@ -41,7 +41,6 @@ class EthereumLocalReader(
    private val reader: EthereumCachingReader,
    private val methods: CallMethods,
    private val head: Head,
-    private val localEnabled: Boolean,
 ) : JsonRpcReader {

    override fun read(key: JsonRpcRequest): Mono<JsonRpcResponse> {
@@ -49,9 +48,6 @@ class EthereumLocalReader(
            return Mono.just(methods.executeHardcoded(key.method))
                .map { JsonRpcResponse(it, null) }
        }
-        if (!localEnabled) {
-            return Mono.empty()
-        }
        if (!methods.isCallable(key.method)) {
            return Mono.error(RpcException(RpcResponseError.CODE_METHOD_NOT_EXIST, "Unsupported method"))
        }
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumMultistream.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumMultistream.kt
@@ -1,215 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2020 ETCDEV GmbH
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import io.emeraldpay.api.proto.BlockchainOuterClass
-import io.emeraldpay.dshackle.Chain
-import io.emeraldpay.dshackle.cache.Caches
-import io.emeraldpay.dshackle.config.UpstreamsConfig
-import io.emeraldpay.dshackle.data.BlockContainer
-import io.emeraldpay.dshackle.reader.JsonRpcReader
-import io.emeraldpay.dshackle.reader.Reader
-import io.emeraldpay.dshackle.upstream.DistanceExtractor
-import io.emeraldpay.dshackle.upstream.DynamicMergedHead
-import io.emeraldpay.dshackle.upstream.EgressSubscription
-import io.emeraldpay.dshackle.upstream.EmptyHead
-import io.emeraldpay.dshackle.upstream.Head
-import io.emeraldpay.dshackle.upstream.HeadLagObserver
-import io.emeraldpay.dshackle.upstream.Lifecycle
-import io.emeraldpay.dshackle.upstream.MergedHead
-import io.emeraldpay.dshackle.upstream.Multistream
-import io.emeraldpay.dshackle.upstream.Selector
-import io.emeraldpay.dshackle.upstream.Upstream
-import io.emeraldpay.dshackle.upstream.ethereum.subscribe.AggregatedPendingTxes
-import io.emeraldpay.dshackle.upstream.ethereum.subscribe.NoPendingTxes
-import io.emeraldpay.dshackle.upstream.ethereum.subscribe.PendingTxesSource
-import io.emeraldpay.dshackle.upstream.forkchoice.MostWorkForkChoice
-import io.emeraldpay.dshackle.upstream.forkchoice.PriorityForkChoice
-import io.emeraldpay.dshackle.upstream.grpc.GrpcUpstream
-import io.emeraldpay.etherjar.domain.BlockHash
-import org.springframework.cloud.sleuth.Tracer
-import org.springframework.util.ConcurrentReferenceHashMap
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import reactor.core.scheduler.Scheduler
-
-@Suppress("UNCHECKED_CAST")
-open class EthereumMultistream(
-    chain: Chain,
-    val upstreams: MutableList<EthereumLikeUpstream>,
-    caches: Caches,
-    private val headScheduler: Scheduler,
-    tracer: Tracer,
-) : Multistream(chain, upstreams as MutableList<Upstream>, caches) {
-
-    private var head: DynamicMergedHead = DynamicMergedHead(
-        PriorityForkChoice(),
-        "ETH Multistream of ${chain.chainCode}",
-        headScheduler,
-    )
-
-    private val filteredHeads: MutableMap<String, Head> =
-        ConcurrentReferenceHashMap(16, ConcurrentReferenceHashMap.ReferenceType.WEAK)
-
-    private val reader: EthereumCachingReader = EthereumCachingReader(this, this.caches, getMethodsFactory(), tracer)
-    private var subscribe = EthereumEgressSubscription(this, headScheduler, NoPendingTxes())
-
-    init {
-        this.init()
-    }
-
-    override fun init() {
-        if (upstreams.size > 0) {
-            upstreams.forEach { addHead(it) }
-        }
-        super.init()
-    }
-
-    override fun onUpstreamsUpdated() {
-        super.onUpstreamsUpdated()
-
-        val pendingTxes: PendingTxesSource = upstreams
-            .mapNotNull {
-                it.getIngressSubscription().getPendingTxes()
-            }.let {
-                if (it.isEmpty()) {
-                    NoPendingTxes()
-                } else if (it.size == 1) {
-                    it.first()
-                } else {
-                    AggregatedPendingTxes(it)
-                }
-            }
-        subscribe = EthereumEgressSubscription(this, headScheduler, pendingTxes)
-    }
-
-    override fun start() {
-        super.start()
-        head.start()
-        onHeadUpdated(head)
-        reader.start()
-    }
-
-    override fun stop() {
-        super.stop()
-        reader.stop()
-        filteredHeads.clear()
-    }
-
-    override fun addHead(upstream: Upstream) {
-        val newHead = upstream.getHead()
-        if (newHead is Lifecycle && !newHead.isRunning()) {
-            newHead.start()
-        }
-        head.addHead(upstream)
-    }
-
-    override fun removeHead(upstreamId: String) {
-        head.removeHead(upstreamId)
-    }
-
-    override fun makeLagObserver(): HeadLagObserver =
-        HeadLagObserver(head, upstreams, DistanceExtractor::extractPowDistance, headScheduler, 6).apply {
-            start()
-        }
-
-    override fun isRunning(): Boolean {
-        return super.isRunning() || reader.isRunning()
-    }
-
-    override fun getCachingReader(): EthereumCachingReader {
-        return reader
-    }
-
-    override fun getHead(): Head {
-        return head
-    }
-
-    override fun tryProxySubscribe(
-        matcher: Selector.Matcher,
-        request: BlockchainOuterClass.NativeSubscribeRequest,
-    ): Flux<out Any>? =
-        upstreams.filter {
-            matcher.matches(it)
-        }.takeIf { ups ->
-            ups.size == 1 && ups.all { it.isGrpc() }
-        }?.map {
-            it as GrpcUpstream
-        }?.map {
-            it.getBlockchainApi().nativeSubscribe(request)
-        }?.let {
-            Flux.merge(it)
-        }
-
-    override fun getLabels(): Collection<UpstreamsConfig.Labels> {
-        return upstreams.flatMap { it.getLabels() }
-    }
-
-    @Suppress("UNCHECKED_CAST")
-    override fun <T : Upstream> cast(selfType: Class<T>): T {
-        if (!selfType.isAssignableFrom(this.javaClass)) {
-            throw ClassCastException("Cannot cast ${this.javaClass} to $selfType")
-        }
-        return this as T
-    }
-
-    override fun getEgressSubscription(): EgressSubscription {
-        return subscribe
-    }
-
-    override fun getLocalReader(localEnabled: Boolean): Mono<JsonRpcReader> {
-        return Mono.just(EthereumLocalReader(reader, getMethods(), getHead(), localEnabled))
-    }
-
-    override fun getHead(mather: Selector.Matcher): Head =
-        filteredHeads.computeIfAbsent(mather.describeInternal().intern()) { _ ->
-            upstreams.filter { mather.matches(it) }
-                .apply {
-                    log.debug("Found $size upstreams matching [${mather.describeInternal()}]")
-                }.let {
-                    val selected = it.map { it.getHead() }
-                    when (it.size) {
-                        0 -> EmptyHead()
-                        1 -> selected.first()
-                        else -> MergedHead(selected, MostWorkForkChoice(), headScheduler, "Eth head ${it.map { it.getId() }}").apply {
-                            start()
-                        }
-                    }
-                }
-        }
-
-    override fun getEnrichedHead(mather: Selector.Matcher): Head =
-        filteredHeads.computeIfAbsent(mather.describeInternal().intern()) { _ ->
-            upstreams.filter { mather.matches(it) }
-                .apply {
-                    log.debug("Found $size upstreams matching [${mather.describeInternal()}]")
-                }.let {
-                    val selected = it.map { source -> source.getHead() }
-                    EnrichedMergedHead(
-                        selected,
-                        getHead(),
-                        headScheduler,
-                        object :
-                            Reader<BlockHash, BlockContainer> {
-                            override fun read(key: BlockHash): Mono<BlockContainer> {
-                                return reader.blocksByHashAsCont().read(key).map { res -> res.data }
-                            }
-                        },
-                    )
-                }
-        }
-}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumPriorityFees.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumPriorityFees.kt
@@ -1,59 +0,0 @@
-/**
- * Copyright (c) 2021 EmeraldPay, Inc
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import io.emeraldpay.api.proto.BlockchainOuterClass
-import io.emeraldpay.dshackle.upstream.Multistream
-import io.emeraldpay.dshackle.upstream.ethereum.json.BlockJson
-import io.emeraldpay.dshackle.upstream.ethereum.json.TransactionJsonSnapshot
-import io.emeraldpay.etherjar.domain.Wei
-import io.emeraldpay.etherjar.rpc.json.TransactionRefJson
-import org.slf4j.LoggerFactory
-import java.util.function.Function
-
-class EthereumPriorityFees(upstreams: Multistream, reader: EthereumCachingReader, heightLimit: Int) :
-    EthereumFees(upstreams, reader, heightLimit) {
-
-    companion object {
-        private val log = LoggerFactory.getLogger(EthereumPriorityFees::class.java)
-    }
-
-    private val toGrpc: Function<EthereumFee, BlockchainOuterClass.EstimateFeeResponse> =
-        Function {
-            BlockchainOuterClass.EstimateFeeResponse.newBuilder()
-                .setEthereumExtended(
-                    BlockchainOuterClass.EthereumExtFees.newBuilder()
-                        .setMax(it.max.amount.toString())
-                        .setPriority(it.priority.amount.toString())
-                        .setExpect(it.paid.amount.toString()),
-                )
-                .build()
-        }
-
-    override fun extractFee(block: BlockJson<TransactionRefJson>, tx: TransactionJsonSnapshot): EthereumFee {
-        val baseFee = block.baseFeePerGas ?: Wei.ZERO
-        if (tx.type == 2) {
-            // an EIP-1559 Transaction provides Max and Priority fee
-            val paid = (baseFee + tx.maxPriorityFeePerGas).coerceAtMost(tx.maxFeePerGas)
-            return EthereumFee(tx.maxFeePerGas, tx.maxPriorityFeePerGas, paid, baseFee)
-        }
-        return EthereumFee(tx.gasPrice, (tx.gasPrice - baseFee).coerceAtLeast(Wei.ZERO), tx.gasPrice, baseFee)
-    }
-
-    override fun getResponseBuilder(): Function<EthereumFee, BlockchainOuterClass.EstimateFeeResponse> {
-        return toGrpc
-    }
-}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumUpstreamValidator.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/EthereumUpstreamValidator.kt
@@ -20,12 +20,12 @@ import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.Defaults
 import io.emeraldpay.dshackle.Global
+import io.emeraldpay.dshackle.config.ChainsConfig.ChainConfig
 import io.emeraldpay.dshackle.foundation.ChainOptions
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.emeraldpay.dshackle.upstream.UpstreamAvailability
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstreamValidator.ValidateUpstreamSettingsResult.UPSTREAM_FATAL_SETTINGS_ERROR
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstreamValidator.ValidateUpstreamSettingsResult.UPSTREAM_SETTINGS_ERROR
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstreamValidator.ValidateUpstreamSettingsResult.UPSTREAM_VALID
+import io.emeraldpay.dshackle.upstream.UpstreamValidator
+import io.emeraldpay.dshackle.upstream.ValidateUpstreamSettingsResult
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.emeraldpay.etherjar.domain.Address
@@ -47,8 +47,8 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
    private val chain: Chain,
    private val upstream: Upstream,
    private val options: ChainOptions.Options,
-    private val callLimitContract: String? = null,
-) {
+    private val config: ChainConfig,
+) : UpstreamValidator {
    companion object {
        private val log = LoggerFactory.getLogger(EthereumUpstreamValidator::class.java)
        val scheduler =
@@ -127,7 +127,7 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
            .onErrorReturn(UpstreamAvailability.UNAVAILABLE)
    }

-    fun start(): Flux<UpstreamAvailability> {
+    override fun start(): Flux<UpstreamAvailability> {
        return Flux.interval(
            Duration.ZERO,
            Duration.ofSeconds(options.validationInterval.toLong()),
@@ -140,13 +140,9 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
            }
    }

-    fun validateUpstreamSettingsOnStartup(): ValidateUpstreamSettingsResult {
-        return validateUpstreamSettings().block() ?: UPSTREAM_FATAL_SETTINGS_ERROR
-    }
-
-    fun validateUpstreamSettings(): Mono<ValidateUpstreamSettingsResult> {
+    override fun validateUpstreamSettings(): Mono<ValidateUpstreamSettingsResult> {
        if (options.disableUpstreamValidation) {
-            return Mono.just(UPSTREAM_VALID)
+            return Mono.just(ValidateUpstreamSettingsResult.UPSTREAM_VALID)
        }
        return Mono.zip(
            validateChain(),
@@ -159,7 +155,7 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(

    private fun validateChain(): Mono<ValidateUpstreamSettingsResult> {
        if (!options.validateChain) {
-            return Mono.just(UPSTREAM_VALID)
+            return Mono.just(ValidateUpstreamSettingsResult.UPSTREAM_VALID)
        }
        return Mono.zip(
            chainId(),
@@ -178,20 +174,20 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
                }

                if (isChainValid) {
-                    UPSTREAM_VALID
+                    ValidateUpstreamSettingsResult.UPSTREAM_VALID
                } else {
-                    UPSTREAM_FATAL_SETTINGS_ERROR
+                    ValidateUpstreamSettingsResult.UPSTREAM_FATAL_SETTINGS_ERROR
                }
            }
            .onErrorResume {
                log.error("Error during chain validation", it)
-                Mono.just(UPSTREAM_SETTINGS_ERROR)
+                Mono.just(ValidateUpstreamSettingsResult.UPSTREAM_SETTINGS_ERROR)
            }
    }

    private fun validateCallLimit(): Mono<ValidateUpstreamSettingsResult> {
-        if (!options.validateCallLimit || callLimitContract == null) {
-            return Mono.just(UPSTREAM_VALID)
+        if (!options.validateCallLimit || config.callLimitContract == null) {
+            return Mono.just(ValidateUpstreamSettingsResult.UPSTREAM_VALID)
        }
        return upstream.getIngressReader()
            .read(
@@ -199,7 +195,7 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
                    "eth_call",
                    listOf(
                        TransactionCallJson(
-                            Address.from(callLimitContract),
+                            Address.from(config.callLimitContract),
                            // calling contract with param 200_000, meaning it will generate 200k symbols or response
                            // f4240 + metadata — ~1 million
                            HexData.from("0xd8a26e3a00000000000000000000000000000000000000000000000000000000000f4240"),
@@ -209,7 +205,7 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
                ),
            )
            .flatMap(JsonRpcResponse::requireResult)
-            .map { UPSTREAM_VALID }
+            .map { ValidateUpstreamSettingsResult.UPSTREAM_VALID }
            .onErrorResume {
                if (it.message != null && it.message!!.contains("rpc.returndata.limit")) {
                    log.warn(
@@ -217,7 +213,7 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
                            "You need to set up your return limit to at least 1_100_000. " +
                            "Erigon config example: https://github.com/ledgerwatch/erigon/blob/d014da4dc039ea97caf04ed29feb2af92b7b129d/cmd/utils/flags.go#L369",
                    )
-                    Mono.just(UPSTREAM_FATAL_SETTINGS_ERROR)
+                    Mono.just(ValidateUpstreamSettingsResult.UPSTREAM_FATAL_SETTINGS_ERROR)
                } else {
                    Mono.error(it)
                }
@@ -233,7 +229,7 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
                        "message ${ctx.exception().message}",
                )
            }
-            .onErrorReturn(UPSTREAM_SETTINGS_ERROR)
+            .onErrorReturn(ValidateUpstreamSettingsResult.UPSTREAM_SETTINGS_ERROR)
    }

    private fun validateOldBlocks(): Mono<ValidateUpstreamSettingsResult> {
@@ -257,11 +253,11 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
                        "Node ${upstream.getId()} probably is synced incorrectly, it is not possible to get old blocks",
                    )
                }
-                UPSTREAM_VALID
+                ValidateUpstreamSettingsResult.UPSTREAM_VALID
            }
            .onErrorResume {
                log.warn("Error during old blocks validation", it)
-                Mono.just(UPSTREAM_VALID)
+                Mono.just(ValidateUpstreamSettingsResult.UPSTREAM_VALID)
            }
    }

@@ -290,10 +286,4 @@ open class EthereumUpstreamValidator @JvmOverloads constructor(
            .doOnError { log.error("Error during execution 'net_version' - ${it.message} for ${upstream.getId()}") }
            .flatMap(JsonRpcResponse::requireStringResult)
    }
-
-    enum class ValidateUpstreamSettingsResult {
-        UPSTREAM_VALID,
-        UPSTREAM_SETTINGS_ERROR,
-        UPSTREAM_FATAL_SETTINGS_ERROR,
-    }
 }
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/subscribe/EthereumLabelsDetector.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum/subscribe/EthereumLabelsDetector.kt
@@ -5,6 +5,7 @@ import com.fasterxml.jackson.module.kotlin.readValue
 import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.Global.Companion.objectMapper
 import io.emeraldpay.dshackle.reader.JsonRpcReader
+import io.emeraldpay.dshackle.upstream.LabelsDetector
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumArchiveBlockNumberReader
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
@@ -14,10 +15,10 @@ import reactor.core.publisher.Mono
 class EthereumLabelsDetector(
    private val reader: JsonRpcReader,
    private val chain: Chain,
-) {
+) : LabelsDetector {
    private val blockNumberReader = EthereumArchiveBlockNumberReader(reader)

-    fun detectLabels(): Flux<Pair<String, String>> {
+    override fun detectLabels(): Flux<Pair<String, String>> {
        return Flux.merge(
            detectNodeType(),
            detectArchiveNode(),
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum_pos/EthereumPosMultiStream.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/ethereum_pos/EthereumPosMultiStream.kt
@@ -1,222 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2020 ETCDEV GmbH
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import io.emeraldpay.api.proto.BlockchainOuterClass
-import io.emeraldpay.dshackle.Chain
-import io.emeraldpay.dshackle.cache.Caches
-import io.emeraldpay.dshackle.config.UpstreamsConfig
-import io.emeraldpay.dshackle.data.BlockContainer
-import io.emeraldpay.dshackle.reader.JsonRpcReader
-import io.emeraldpay.dshackle.reader.Reader
-import io.emeraldpay.dshackle.upstream.DistanceExtractor
-import io.emeraldpay.dshackle.upstream.DynamicMergedHead
-import io.emeraldpay.dshackle.upstream.EmptyHead
-import io.emeraldpay.dshackle.upstream.Head
-import io.emeraldpay.dshackle.upstream.HeadLagObserver
-import io.emeraldpay.dshackle.upstream.Lifecycle
-import io.emeraldpay.dshackle.upstream.MergedHead
-import io.emeraldpay.dshackle.upstream.Multistream
-import io.emeraldpay.dshackle.upstream.Selector
-import io.emeraldpay.dshackle.upstream.Upstream
-import io.emeraldpay.dshackle.upstream.ethereum.subscribe.AggregatedPendingTxes
-import io.emeraldpay.dshackle.upstream.ethereum.subscribe.NoPendingTxes
-import io.emeraldpay.dshackle.upstream.ethereum.subscribe.PendingTxesSource
-import io.emeraldpay.dshackle.upstream.forkchoice.PriorityForkChoice
-import io.emeraldpay.dshackle.upstream.grpc.GrpcUpstream
-import io.emeraldpay.etherjar.domain.BlockHash
-import org.springframework.cloud.sleuth.Tracer
-import org.springframework.util.ConcurrentReferenceHashMap
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import reactor.core.scheduler.Scheduler
-
-@Suppress("UNCHECKED_CAST")
-open class EthereumPosMultiStream(
-    chain: Chain,
-    val upstreams: MutableList<EthereumLikeUpstream>,
-    caches: Caches,
-    private val headScheduler: Scheduler,
-    tracer: Tracer,
-) : Multistream(chain, upstreams as MutableList<Upstream>, caches) {
-
-    private var head: DynamicMergedHead = DynamicMergedHead(
-        PriorityForkChoice(),
-        "ETH Pos Multistream of ${chain.chainCode}",
-        headScheduler,
-    )
-
-    private val reader: EthereumCachingReader = EthereumCachingReader(this, this.caches, getMethodsFactory(), tracer)
-    private var subscribe = EthereumEgressSubscription(this, headScheduler, NoPendingTxes())
-    private val filteredHeads: MutableMap<String, Head> =
-        ConcurrentReferenceHashMap(16, ConcurrentReferenceHashMap.ReferenceType.WEAK)
-
-    init {
-        this.init()
-    }
-
-    override fun init() {
-        if (upstreams.size > 0) {
-            upstreams.forEach { addHead(it) }
-        }
-        super.init()
-    }
-
-    override fun start() {
-        super.start()
-        head.start()
-        onHeadUpdated(head)
-        reader.start()
-    }
-
-    override fun stop() {
-        super.stop()
-        reader.stop()
-        filteredHeads.clear()
-    }
-
-    override fun addHead(upstream: Upstream) {
-        val newHead = upstream.getHead()
-        if (newHead is Lifecycle && !newHead.isRunning()) {
-            newHead.start()
-        }
-        head.addHead(upstream)
-    }
-
-    override fun removeHead(upstreamId: String) {
-        head.removeHead(upstreamId)
-    }
-
-    override fun isRunning(): Boolean {
-        return super.isRunning() || reader.isRunning()
-    }
-
-    override fun makeLagObserver(): HeadLagObserver =
-        HeadLagObserver(head, upstreams, DistanceExtractor::extractPriorityDistance, headScheduler, 6).apply {
-            start()
-        }
-
-    override fun getCachingReader(): EthereumCachingReader {
-        return reader
-    }
-
-    override fun getHead(): Head {
-        return head
-    }
-
-    override fun tryProxySubscribe(
-        matcher: Selector.Matcher,
-        request: BlockchainOuterClass.NativeSubscribeRequest,
-    ): Flux<out Any>? =
-        upstreams.filter {
-            matcher.matches(it)
-        }.takeIf { ups ->
-            ups.size == 1 && ups.all { it.isGrpc() }
-        }?.map {
-            it as GrpcUpstream
-        }?.map {
-            it.proxySubscribe(request)
-        }?.let {
-            Flux.merge(it)
-        }
-
-    override fun getLabels(): Collection<UpstreamsConfig.Labels> {
-        return upstreams.flatMap { it.getLabels() }
-    }
-
-    @Suppress("UNCHECKED_CAST")
-    override fun <T : Upstream> cast(selfType: Class<T>): T {
-        if (!selfType.isAssignableFrom(this.javaClass)) {
-            throw ClassCastException("Cannot cast ${this.javaClass} to $selfType")
-        }
-        return this as T
-    }
-
-    override fun getLocalReader(localEnabled: Boolean): Mono<JsonRpcReader> {
-        return Mono.just(EthereumLocalReader(reader, getMethods(), getHead(), localEnabled))
-    }
-
-    override fun getEgressSubscription(): EthereumEgressSubscription {
-        return subscribe
-    }
-
-    override fun getHead(mather: Selector.Matcher): Head =
-        if (mather == Selector.empty || mather == Selector.anyLabel) {
-            head
-        } else {
-            filteredHeads.computeIfAbsent(mather.describeInternal().intern()) { _ ->
-                upstreams.filter { mather.matches(it) }
-                    .apply {
-                        log.debug("Found $size upstreams matching [${mather.describeInternal()}]")
-                    }
-                    .let {
-                        val selected = it.map { it.getHead() }
-                        when (it.size) {
-                            0 -> EmptyHead()
-                            1 -> selected.first()
-                            else -> MergedHead(
-                                selected,
-                                PriorityForkChoice(),
-                                headScheduler,
-                                "ETH head for ${it.map { it.getId() }}",
-                            ).apply {
-                                start()
-                            }
-                        }
-                    }
-            }
-        }
-
-    override fun getEnrichedHead(mather: Selector.Matcher): Head =
-        filteredHeads.computeIfAbsent(mather.describeInternal().intern()) { _ ->
-            upstreams.filter { mather.matches(it) }
-                .apply {
-                    log.debug("Found $size upstreams matching [${mather.describeInternal()}]")
-                }.let {
-                    val selected = it.map { source -> source.getHead() }
-                    EnrichedMergedHead(
-                        selected,
-                        getHead(),
-                        headScheduler,
-                        object :
-                            Reader<BlockHash, BlockContainer> {
-                            override fun read(key: BlockHash): Mono<BlockContainer> {
-                                return reader.blocksByHashAsCont().read(key).map { res -> res.data }
-                            }
-                        },
-                    )
-                }
-        }
-
-    override fun onUpstreamsUpdated() {
-        super.onUpstreamsUpdated()
-
-        val pendingTxes: PendingTxesSource = upstreams
-            .mapNotNull {
-                it.getIngressSubscription().getPendingTxes()
-            }.let {
-                if (it.isEmpty()) {
-                    NoPendingTxes()
-                } else if (it.size == 1) {
-                    it.first()
-                } else {
-                    AggregatedPendingTxes(it)
-                }
-            }
-        subscribe = EthereumEgressSubscription(this, headScheduler, pendingTxes)
-    }
-}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/ChainSpecific.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/ChainSpecific.kt
@@ -3,19 +3,53 @@ package io.emeraldpay.dshackle.upstream.generic
 import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.BlockchainType.STARKNET
 import io.emeraldpay.dshackle.Chain
+import io.emeraldpay.dshackle.cache.Caches
+import io.emeraldpay.dshackle.config.ChainsConfig.ChainConfig
 import io.emeraldpay.dshackle.data.BlockContainer
+import io.emeraldpay.dshackle.foundation.ChainOptions
+import io.emeraldpay.dshackle.reader.JsonRpcReader
+import io.emeraldpay.dshackle.upstream.CachingReader
+import io.emeraldpay.dshackle.upstream.EgressSubscription
+import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.LabelsDetector
+import io.emeraldpay.dshackle.upstream.Multistream
+import io.emeraldpay.dshackle.upstream.Upstream
+import io.emeraldpay.dshackle.upstream.UpstreamValidator
+import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumChainSpecific
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import io.emeraldpay.dshackle.upstream.starknet.StarknetChainSpecific
+import org.apache.commons.collections4.Factory
+import org.springframework.cloud.sleuth.Tracer
+import reactor.core.publisher.Mono
+import reactor.core.scheduler.Scheduler
+
+typealias SubscriptionBuilder = (Multistream) -> EgressSubscription
+typealias LocalReaderBuilder = (CachingReader, CallMethods, Head) -> Mono<JsonRpcReader>
+typealias CachingReaderBuilder = (Multistream, Caches, Factory<CallMethods>) -> CachingReader

 interface ChainSpecific {
    fun parseBlock(data: JsonRpcResponse, upstreamId: String): BlockContainer

    fun latestBlockRequest(): JsonRpcRequest
+
+    fun localReaderBuilder(cachingReader: CachingReader, methods: CallMethods, head: Head): Mono<JsonRpcReader>
+
+    fun subscriptionBuilder(headScheduler: Scheduler): (Multistream) -> EgressSubscription
+
+    fun makeCachingReaderBuilder(tracer: Tracer): CachingReaderBuilder
+
+    fun validator(chain: Chain, upstream: Upstream, options: ChainOptions.Options, config: ChainConfig): UpstreamValidator?
+
+    fun labelDetector(chain: Chain, reader: JsonRpcReader): LabelsDetector?
+
+    fun subscriptionTopics(upstream: GenericUpstream): List<String>
 }

 object ChainSpecificRegistry {
+
+    @JvmStatic
    fun resolve(chain: Chain): ChainSpecific {
        if (BlockchainType.from(chain) == STARKNET) {
            return StarknetChainSpecific
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/GenericMultistream.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/GenericMultistream.kt
@@ -16,6 +16,7 @@
 */
 package io.emeraldpay.dshackle.upstream.generic

+import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.cache.Caches
 import io.emeraldpay.dshackle.config.UpstreamsConfig
@@ -24,24 +25,42 @@ import io.emeraldpay.dshackle.upstream.CachingReader
 import io.emeraldpay.dshackle.upstream.DistanceExtractor
 import io.emeraldpay.dshackle.upstream.DynamicMergedHead
 import io.emeraldpay.dshackle.upstream.EgressSubscription
-import io.emeraldpay.dshackle.upstream.EmptyEgressSubscription
+import io.emeraldpay.dshackle.upstream.EmptyHead
 import io.emeraldpay.dshackle.upstream.Head
 import io.emeraldpay.dshackle.upstream.HeadLagObserver
 import io.emeraldpay.dshackle.upstream.Lifecycle
+import io.emeraldpay.dshackle.upstream.MergedHead
 import io.emeraldpay.dshackle.upstream.Multistream
+import io.emeraldpay.dshackle.upstream.Selector
 import io.emeraldpay.dshackle.upstream.Selector.Matcher
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.emeraldpay.dshackle.upstream.forkchoice.PriorityForkChoice
+import io.emeraldpay.dshackle.upstream.grpc.GrpcUpstream
+import org.springframework.util.ConcurrentReferenceHashMap
+import org.springframework.util.ConcurrentReferenceHashMap.ReferenceType.WEAK
+import reactor.core.publisher.Flux
 import reactor.core.publisher.Mono
 import reactor.core.scheduler.Scheduler

-@Suppress("UNCHECKED_CAST")
 open class GenericMultistream(
    chain: Chain,
-    val upstreams: MutableList<GenericUpstream>,
+    private val upstreams: MutableList<Upstream>,
    caches: Caches,
    private val headScheduler: Scheduler,
-) : Multistream(chain, upstreams as MutableList<Upstream>, caches) {
+    cachingReaderBuilder: CachingReaderBuilder,
+    private val localReaderBuilder: LocalReaderBuilder,
+    private val subscriptionBuilder: SubscriptionBuilder,
+) : Multistream(chain, caches) {
+
+    private val cachingReader = cachingReaderBuilder(this, caches, getMethodsFactory())
+
+    override fun getUpstreams(): MutableList<out Upstream> {
+        return upstreams
+    }
+
+    override fun addUpstreamInternal(u: Upstream) {
+        upstreams.add(u as GenericUpstream)
+    }

    private var head: DynamicMergedHead = DynamicMergedHead(
        PriorityForkChoice(),
@@ -53,6 +72,8 @@ open class GenericMultistream(
        this.init()
    }

+    private var subscription: EgressSubscription = subscriptionBuilder(this)
+
    override fun init() {
        if (upstreams.size > 0) {
            upstreams.forEach { addHead(it) }
@@ -60,10 +81,20 @@ open class GenericMultistream(
        super.init()
    }

+    private val filteredHeads: MutableMap<String, Head> =
+        ConcurrentReferenceHashMap(16, WEAK)
+
    override fun start() {
        super.start()
        head.start()
        onHeadUpdated(head)
+        cachingReader.start()
+    }
+
+    override fun stop() {
+        super.stop()
+        cachingReader.stop()
+        filteredHeads.clear()
    }

    override fun addHead(upstream: Upstream) {
@@ -78,17 +109,45 @@ open class GenericMultistream(
        head.removeHead(upstreamId)
    }

+    override fun isRunning(): Boolean {
+        return super.isRunning() || cachingReader.isRunning()
+    }
+
    override fun makeLagObserver(): HeadLagObserver =
        HeadLagObserver(head, upstreams, DistanceExtractor::extractPriorityDistance, headScheduler, 6).apply {
            start()
        }

    override fun getCachingReader(): CachingReader? {
-        return null
+        return cachingReader
    }

    override fun getHead(mather: Matcher): Head {
-        return getHead()
+        if (mather == Selector.empty || mather == Selector.anyLabel) {
+            return head
+        } else {
+            return filteredHeads.computeIfAbsent(mather.describeInternal().intern()) { _ ->
+                upstreams.filter { mather.matches(it) }
+                    .apply {
+                        log.debug("Found $size upstreams matching [${mather.describeInternal()}]")
+                    }
+                    .let {
+                        val selected = it.map { it.getHead() }
+                        when (it.size) {
+                            0 -> EmptyHead()
+                            1 -> selected.first()
+                            else -> MergedHead(
+                                selected,
+                                PriorityForkChoice(),
+                                headScheduler,
+                                "Head for ${it.map { it.getId() }}",
+                            ).apply {
+                                start()
+                            }
+                        }
+                    }
+            }
+        }
    }

    override fun getHead(): Head {
@@ -111,11 +170,32 @@ open class GenericMultistream(
        return this as T
    }

-    override fun getLocalReader(localEnabled: Boolean): Mono<JsonRpcReader> {
-        return Mono.just(LocalReader(getMethods()))
+    override fun getLocalReader(): Mono<JsonRpcReader> {
+        return localReaderBuilder(cachingReader, getMethods(), getHead())
    }

    override fun getEgressSubscription(): EgressSubscription {
-        return EmptyEgressSubscription()
+        return subscription
    }
+
+    override fun onUpstreamsUpdated() {
+        super.onUpstreamsUpdated()
+        subscription = subscriptionBuilder(this)
+    }
+
+    override fun tryProxySubscribe(
+        matcher: Matcher,
+        request: BlockchainOuterClass.NativeSubscribeRequest,
+    ): Flux<out Any>? =
+        upstreams.filter {
+            matcher.matches(it)
+        }.takeIf { ups ->
+            ups.size == 1 && ups.all { it.isGrpc() }
+        }?.map {
+            it as GrpcUpstream
+        }?.map {
+            it.proxySubscribe(request)
+        }?.let {
+            Flux.merge(it)
+        }
 }
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/GenericUpstream.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/GenericUpstream.kt
@@ -8,21 +8,27 @@ import io.emeraldpay.dshackle.foundation.ChainOptions
 import io.emeraldpay.dshackle.reader.JsonRpcReader
 import io.emeraldpay.dshackle.startup.QuorumForLabels
 import io.emeraldpay.dshackle.startup.UpstreamChangeEvent
-import io.emeraldpay.dshackle.startup.UpstreamChangeEvent.ChangeType.UPDATED
 import io.emeraldpay.dshackle.upstream.Capability
 import io.emeraldpay.dshackle.upstream.DefaultUpstream
 import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.IngressSubscription
+import io.emeraldpay.dshackle.upstream.LabelsDetectorBuilder
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.emeraldpay.dshackle.upstream.UpstreamAvailability
+import io.emeraldpay.dshackle.upstream.UpstreamValidator
+import io.emeraldpay.dshackle.upstream.UpstreamValidatorBuilder
+import io.emeraldpay.dshackle.upstream.ValidateUpstreamSettingsResult
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.dshackle.upstream.generic.connectors.ConnectorFactory
 import io.emeraldpay.dshackle.upstream.generic.connectors.GenericConnector
 import org.springframework.context.ApplicationEventPublisher
 import org.springframework.context.Lifecycle
 import reactor.core.Disposable
+import reactor.core.publisher.Flux
+import java.time.Duration
 import java.util.concurrent.atomic.AtomicBoolean

-class GenericUpstream(
+open class GenericUpstream(
    id: String,
    val chain: Chain,
    hash: Byte,
@@ -30,14 +36,23 @@ class GenericUpstream(
    role: UpstreamsConfig.UpstreamRole,
    targets: CallMethods?,
    private val node: QuorumForLabels.QuorumItem?,
-    val chainConfig: ChainsConfig.ChainConfig,
+    chainConfig: ChainsConfig.ChainConfig,
    connectorFactory: ConnectorFactory,
    private val eventPublisher: ApplicationEventPublisher?,
+    validatorBuilder: UpstreamValidatorBuilder,
+    labelsDetectorBuilder: LabelsDetectorBuilder,
+    private val subscriptionTopics: (GenericUpstream) -> List<String>,
 ) : DefaultUpstream(id, hash, null, UpstreamAvailability.OK, options, role, targets, node, chainConfig), Lifecycle {

+    private val validator: UpstreamValidator? = validatorBuilder(chain, this, getOptions(), chainConfig)
+    private var validatorSubscription: Disposable? = null
+    private var validationSettingsSubscription: Disposable? = null
+
    private val hasLiveSubscriptionHead: AtomicBoolean = AtomicBoolean(false)
-    private val connector: GenericConnector = connectorFactory.create(this, chain, true)
+    protected val connector: GenericConnector = connectorFactory.create(this, chain, true)
    private var livenessSubscription: Disposable? = null
+    private val labelsDetector = labelsDetectorBuilder(chain, this.getIngressReader())
+
    override fun getHead(): Head {
        return connector.getHead()
    }
@@ -51,10 +66,7 @@ class GenericUpstream(
    }

    override fun getSubscriptionTopics(): List<String> {
-        // should be implemented in next iterations
-        // starknet doesn't have any subscriptions at all
-        // polkadot serves subscriptions like separate json-rpc methods
-        return emptyList()
+        return subscriptionTopics(this)
    }

    // outdated, looks like applicable only for bitcoin and our ws_head trick
@@ -83,19 +95,107 @@ class GenericUpstream(
        log.info("Configured for ${chain.chainName}")
        connector.start()

+        if (validator != null) {
+            val validSettingsResult = validator.validateUpstreamSettingsOnStartup()
+            when (validSettingsResult) {
+                ValidateUpstreamSettingsResult.UPSTREAM_FATAL_SETTINGS_ERROR -> {
+                    connector.stop()
+                    log.warn("Upstream ${getId()} couldn't start, invalid upstream settings")
+                    return
+                }
+                ValidateUpstreamSettingsResult.UPSTREAM_SETTINGS_ERROR -> {
+                    validateUpstreamSettings()
+                }
+                else -> {
+                    upstreamStart()
+                }
+            }
+        } else {
+            upstreamStart()
+        }
+    }
+
+    private fun validateUpstreamSettings() {
+        if (validator != null) {
+            validationSettingsSubscription = Flux.interval(
+                Duration.ofSeconds(10),
+                Duration.ofSeconds(20),
+            ).flatMap {
+                validator.validateUpstreamSettings()
+            }.subscribe {
+                when (it) {
+                    ValidateUpstreamSettingsResult.UPSTREAM_FATAL_SETTINGS_ERROR -> {
+                        connector.stop()
+                        disposeValidationSettingsSubscription()
+                    }
+
+                    ValidateUpstreamSettingsResult.UPSTREAM_VALID -> {
+                        upstreamStart()
+                        eventPublisher?.publishEvent(
+                            UpstreamChangeEvent(
+                                chain,
+                                this,
+                                UpstreamChangeEvent.ChangeType.ADDED,
+                            ),
+                        )
+                        disposeValidationSettingsSubscription()
+                    }
+
+                    else -> {
+                        log.warn("Continue validation of upstream ${getId()}")
+                    }
+                }
+            }
+        }
+    }
+
+    private fun detectLabels() {
+        labelsDetector?.detectLabels()?.subscribe { label -> updateLabels(label) }
+    }
+
+    private fun upstreamStart() {
+        if (getOptions().disableValidation) {
+            log.warn("Disable validation for upstream ${this.getId()}")
+            this.setLag(0)
+            this.setStatus(UpstreamAvailability.OK)
+        } else {
+            log.debug("Start validation for upstream ${this.getId()}")
+            validatorSubscription = validator?.start()
+                ?.subscribe(this::setStatus)
+        }
        livenessSubscription = connector.hasLiveSubscriptionHead().subscribe({
            hasLiveSubscriptionHead.set(it)
-            eventPublisher?.publishEvent(UpstreamChangeEvent(chain, this, UPDATED))
+            eventPublisher?.publishEvent(UpstreamChangeEvent(chain, this, UpstreamChangeEvent.ChangeType.UPDATED))
        }, {
            log.debug("Error while checking live subscription for ${getId()}", it)
        },)
+        detectLabels()
    }

    override fun stop() {
+        validatorSubscription?.dispose()
+        validatorSubscription = null
        livenessSubscription?.dispose()
        livenessSubscription = null
+        disposeValidationSettingsSubscription()
        connector.stop()
    }

+    private fun disposeValidationSettingsSubscription() {
+        validationSettingsSubscription?.dispose()
+        validationSettingsSubscription = null
+    }
+
+    private fun updateLabels(label: Pair<String, String>) {
+        log.info("Detected label ${label.first} with value ${label.second} for upstream ${getId()}")
+        node?.labels?.let { labels ->
+            labels[label.first] = label.second
+        }
+    }
+
+    fun getIngressSubscription(): IngressSubscription {
+        return connector.getIngressSubscription()
+    }
+
    override fun isRunning() = connector.isRunning()
 }
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/connectors/GenericConnector.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/connectors/GenericConnector.kt
@@ -2,8 +2,8 @@ package io.emeraldpay.dshackle.upstream.generic.connectors

 import io.emeraldpay.dshackle.reader.JsonRpcReader
 import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.IngressSubscription
 import io.emeraldpay.dshackle.upstream.Lifecycle
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumIngressSubscription
 import reactor.core.publisher.Flux

 interface GenericConnector : Lifecycle {
@@ -13,5 +13,5 @@ interface GenericConnector : Lifecycle {

    fun getIngressReader(): JsonRpcReader

-    fun getIngressSubscription(): EthereumIngressSubscription
+    fun getIngressSubscription(): IngressSubscription
 }
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/connectors/GenericRpcConnector.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/connectors/GenericRpcConnector.kt
@@ -7,9 +7,9 @@ import io.emeraldpay.dshackle.reader.JsonRpcReader
 import io.emeraldpay.dshackle.upstream.BlockValidator
 import io.emeraldpay.dshackle.upstream.DefaultUpstream
 import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.IngressSubscription
 import io.emeraldpay.dshackle.upstream.Lifecycle
 import io.emeraldpay.dshackle.upstream.MergedHead
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumIngressSubscription
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumWsHead
 import io.emeraldpay.dshackle.upstream.ethereum.HeadLivenessValidator
 import io.emeraldpay.dshackle.upstream.ethereum.NoEthereumIngressSubscription
@@ -145,7 +145,7 @@ class GenericRpcConnector(
        return directReader
    }

-    override fun getIngressSubscription(): EthereumIngressSubscription {
+    override fun getIngressSubscription(): IngressSubscription {
        return NoEthereumIngressSubscription.DEFAULT
    }

--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/connectors/GenericWsConnector.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/generic/connectors/GenericWsConnector.kt
@@ -4,6 +4,7 @@ import io.emeraldpay.dshackle.reader.JsonRpcReader
 import io.emeraldpay.dshackle.upstream.BlockValidator
 import io.emeraldpay.dshackle.upstream.DefaultUpstream
 import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.IngressSubscription
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumIngressSubscription
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumWsHead
 import io.emeraldpay.dshackle.upstream.ethereum.HeadLivenessValidator
@@ -74,7 +75,7 @@ class GenericWsConnector(
        return reader
    }

-    override fun getIngressSubscription(): EthereumIngressSubscription {
+    override fun getIngressSubscription(): IngressSubscription {
        return subscriptions
    }

--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/grpc/EthereumGrpcUpstream.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/grpc/EthereumGrpcUpstream.kt
@@ -1,223 +0,0 @@
-/**
- * Copyright (c) 2020 EmeraldPay, Inc
- * Copyright (c) 2019 ETCDEV GmbH
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.grpc
-
-import io.emeraldpay.api.proto.BlockchainOuterClass
-import io.emeraldpay.api.proto.ReactorBlockchainGrpc.ReactorBlockchainStub
-import io.emeraldpay.dshackle.Chain
-import io.emeraldpay.dshackle.Defaults
-import io.emeraldpay.dshackle.config.ChainsConfig
-import io.emeraldpay.dshackle.config.UpstreamsConfig
-import io.emeraldpay.dshackle.data.BlockContainer
-import io.emeraldpay.dshackle.data.BlockId
-import io.emeraldpay.dshackle.foundation.ChainOptions
-import io.emeraldpay.dshackle.reader.JsonRpcReader
-import io.emeraldpay.dshackle.startup.QuorumForLabels
-import io.emeraldpay.dshackle.upstream.BuildInfo
-import io.emeraldpay.dshackle.upstream.Capability
-import io.emeraldpay.dshackle.upstream.Head
-import io.emeraldpay.dshackle.upstream.Lifecycle
-import io.emeraldpay.dshackle.upstream.Upstream
-import io.emeraldpay.dshackle.upstream.UpstreamAvailability
-import io.emeraldpay.dshackle.upstream.calls.CallMethods
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumIngressSubscription
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumLikeUpstream
-import io.emeraldpay.dshackle.upstream.ethereum.subscribe.EthereumDshackleIngressSubscription
-import io.emeraldpay.dshackle.upstream.forkchoice.MostWorkForkChoice
-import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcGrpcClient
-import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
-import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
-import io.emeraldpay.etherjar.domain.BlockHash
-import io.emeraldpay.etherjar.rpc.RpcException
-import org.reactivestreams.Publisher
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import reactor.core.scheduler.Scheduler
-import java.math.BigInteger
-import java.time.Instant
-import java.util.Locale
-import java.util.concurrent.TimeoutException
-import java.util.function.Function
-
-open class EthereumGrpcUpstream(
-    private val parentId: String,
-    hash: Byte,
-    role: UpstreamsConfig.UpstreamRole,
-    private val chain: Chain,
-    private val remote: ReactorBlockchainStub,
-    client: JsonRpcGrpcClient,
-    overrideLabels: UpstreamsConfig.Labels?,
-    chainConfig: ChainsConfig.ChainConfig,
-    headScheduler: Scheduler,
-) : EthereumLikeUpstream(
-    "${parentId}_${chain.chainCode.lowercase(Locale.getDefault())}",
-    hash,
-    ChainOptions.PartialOptions.getDefaults().buildOptions(),
-    role,
-    null,
-    null,
-    chainConfig,
-),
-    GrpcUpstream,
-    Lifecycle {
-
-    private val blockConverter: Function<BlockchainOuterClass.ChainHead, BlockContainer> = Function { value ->
-        val parentHash =
-            if (value.parentBlockId.isBlank()) {
-                null
-            } else {
-                BlockId.from(BlockHash.from("0x" + value.parentBlockId))
-            }
-        val block = BlockContainer(
-            value.height,
-            BlockId.from(BlockHash.from("0x" + value.blockId)),
-            BigInteger(1, value.weight.toByteArray()),
-            Instant.ofEpochMilli(value.timestamp),
-            false,
-            null,
-            null,
-            parentHash,
-        )
-        block
-    }
-
-    override fun getSubscriptionTopics(): List<String> {
-        return subscriptionTopics
-    }
-
-    private val reloadBlock: Function<BlockContainer, Publisher<BlockContainer>> = Function { existingBlock ->
-        // head comes without transaction data
-        // need to download transactions for the block
-        defaultReader.read(JsonRpcRequest("eth_getBlockByHash", listOf(existingBlock.hash.toHexWithPrefix(), false)))
-            .flatMap(JsonRpcResponse::requireResult)
-            .map {
-                BlockContainer.fromEthereumJson(it, getId())
-            }
-            .timeout(timeout, Mono.error(TimeoutException("Timeout from upstream")))
-            .doOnError { t ->
-                setStatus(UpstreamAvailability.UNAVAILABLE)
-                val msg = "Failed to download block data for chain $chain on $parentId"
-                if (t is RpcException || t is TimeoutException) {
-                    log.warn("$msg. Message: ${t.message}")
-                } else {
-                    log.error(msg, t)
-                }
-            }
-    }
-
-    private val upstreamStatus = GrpcUpstreamStatus(overrideLabels)
-    private val grpcHead = GrpcHead(
-        getId(),
-        chain,
-        this,
-        remote,
-        blockConverter,
-        reloadBlock,
-        MostWorkForkChoice(),
-        headScheduler,
-    )
-    private var capabilities: Set<Capability> = emptySet()
-    private val buildInfo: BuildInfo = BuildInfo()
-    private var subscriptionTopics = listOf<String>()
-
-    private val defaultReader: JsonRpcReader = client.getReader()
-    var timeout = Defaults.timeout
-    private val ethereumSubscriptions = EthereumDshackleIngressSubscription(chain, remote)
-
-    override fun getBlockchainApi(): ReactorBlockchainStub {
-        return remote
-    }
-
-    override fun proxySubscribe(request: BlockchainOuterClass.NativeSubscribeRequest): Flux<out Any> =
-        remote.nativeSubscribe(request)
-
-    override fun start() {
-    }
-
-    override fun isRunning(): Boolean {
-        return true
-    }
-
-    override fun stop() {
-    }
-
-    override fun getBuildInfo(): BuildInfo {
-        return buildInfo
-    }
-
-    override fun update(conf: BlockchainOuterClass.DescribeChain, buildInfo: BlockchainOuterClass.BuildInfo): Boolean {
-        val newBuildInfo = BuildInfo.extract(buildInfo)
-        val buildInfoChanged = this.buildInfo.update(newBuildInfo)
-        val newCapabilities = RemoteCapabilities.extract(conf)
-        val upstreamStatusChanged = (upstreamStatus.update(conf) || (newCapabilities != capabilities)).also {
-            capabilities = newCapabilities
-        }
-        conf.status?.let { status -> onStatus(status) }
-        val subsChanged = (conf.supportedSubscriptionsList != subscriptionTopics).also {
-            subscriptionTopics = conf.supportedSubscriptionsList
-        }
-        return buildInfoChanged || upstreamStatusChanged || subsChanged
-    }
-
-    override fun getQuorumByLabel(): QuorumForLabels {
-        return upstreamStatus.getNodes()
-    }
-
-    // ------------------------------------------------------------------------------------------
-
-    override fun getLabels(): Collection<UpstreamsConfig.Labels> {
-        return upstreamStatus.getLabels()
-    }
-
-    override fun getIngressSubscription(): EthereumIngressSubscription {
-        return ethereumSubscriptions
-    }
-
-    override fun getMethods(): CallMethods {
-        return upstreamStatus.getCallMethods()
-    }
-
-    override fun isAvailable(): Boolean {
-        return super.isAvailable() && grpcHead.getCurrent() != null && getQuorumByLabel().getAll().any {
-            it.quorum > 0
-        }
-    }
-
-    override fun getHead(): Head {
-        return grpcHead
-    }
-
-    override fun getIngressReader(): JsonRpcReader {
-        return defaultReader
-    }
-
-    @Suppress("UNCHECKED_CAST")
-    override fun <T : Upstream> cast(selfType: Class<T>): T {
-        if (!selfType.isAssignableFrom(this.javaClass)) {
-            throw ClassCastException("Cannot cast ${this.javaClass} to $selfType")
-        }
-        return this as T
-    }
-
-    override fun getCapabilities(): Set<Capability> {
-        return capabilities
-    }
-
-    override fun isGrpc(): Boolean {
-        return true
-    }
-}
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/grpc/EthereumPosGrpcUpstream.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/grpc/EthereumPosGrpcUpstream.kt
@@ -28,13 +28,11 @@ import io.emeraldpay.dshackle.reader.JsonRpcReader
 import io.emeraldpay.dshackle.startup.QuorumForLabels
 import io.emeraldpay.dshackle.upstream.BuildInfo
 import io.emeraldpay.dshackle.upstream.Capability
+import io.emeraldpay.dshackle.upstream.DefaultUpstream
 import io.emeraldpay.dshackle.upstream.Head
 import io.emeraldpay.dshackle.upstream.Lifecycle
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumIngressSubscription
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumLikeUpstream
-import io.emeraldpay.dshackle.upstream.ethereum.subscribe.EthereumDshackleIngressSubscription
 import io.emeraldpay.dshackle.upstream.forkchoice.NoChoiceWithPriorityForkChoice
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcGrpcClient
 import io.emeraldpay.etherjar.domain.BlockHash
@@ -45,7 +43,7 @@ import java.time.Instant
 import java.util.Locale
 import java.util.function.Function

-open class EthereumPosGrpcUpstream(
+open class GenericGrpcUpstream(
    parentId: String,
    hash: Byte,
    role: UpstreamsConfig.UpstreamRole,
@@ -56,7 +54,7 @@ open class EthereumPosGrpcUpstream(
    overrideLabels: UpstreamsConfig.Labels?,
    chainConfig: ChainsConfig.ChainConfig,
    headScheduler: Scheduler,
-) : EthereumLikeUpstream(
+) : DefaultUpstream(
    "${parentId}_${chain.chainCode.lowercase(Locale.getDefault())}",
    hash,
    ChainOptions.PartialOptions.getDefaults().buildOptions(),
@@ -103,7 +101,8 @@ open class EthereumPosGrpcUpstream(
    private val buildInfo: BuildInfo = BuildInfo()

    private val defaultReader: JsonRpcReader = client.getReader()
-    private val ethereumSubscriptions = EthereumDshackleIngressSubscription(chain, remote)
+
+    // private val ethereumSubscriptions = EthereumDshackleIngressSubscription(chain, remote)
    private var subscriptionTopics = listOf<String>()

    override fun start() {
@@ -155,10 +154,6 @@ open class EthereumPosGrpcUpstream(
        return upstreamStatus.getLabels()
    }

-    override fun getIngressSubscription(): EthereumIngressSubscription {
-        return ethereumSubscriptions
-    }
-
    override fun getMethods(): CallMethods {
        return upstreamStatus.getCallMethods()
    }
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/grpc/GrpcUpstreams.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/grpc/GrpcUpstreams.kt
@@ -25,6 +25,7 @@ import io.emeraldpay.api.proto.Common.ChainRef.UNRECOGNIZED
 import io.emeraldpay.api.proto.ReactorAuthGrpc
 import io.emeraldpay.api.proto.ReactorBlockchainGrpc
 import io.emeraldpay.dshackle.BlockchainType
+import io.emeraldpay.dshackle.BlockchainType.BITCOIN
 import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.Defaults
 import io.emeraldpay.dshackle.FileResolver
@@ -34,7 +35,6 @@ import io.emeraldpay.dshackle.config.ChainsConfig
 import io.emeraldpay.dshackle.config.UpstreamsConfig
 import io.emeraldpay.dshackle.startup.UpstreamChangeEvent
 import io.emeraldpay.dshackle.upstream.DefaultUpstream
-import io.emeraldpay.dshackle.upstream.Lifecycle
 import io.emeraldpay.dshackle.upstream.UpstreamAvailability
 import io.emeraldpay.dshackle.upstream.grpc.auth.AuthException
 import io.emeraldpay.dshackle.upstream.grpc.auth.ClientAuthenticationInterceptor
@@ -246,42 +246,37 @@ class GrpcUpstreams(
        return sslContext.build()
    }

-    private val creators: Map<BlockchainType, (chain: Chain, client: JsonRpcGrpcClient) -> DefaultUpstream> = mapOf(
-        BlockchainType.EVM_POW to { chain, rpcClient ->
-            EthereumGrpcUpstream(
-                id,
-                hash,
-                role,
-                chain,
-                client,
-                rpcClient,
-                labels,
-                chainsConfig.resolve(chain.chainName),
-                headScheduler,
-            )
-        },
-        BlockchainType.EVM_POS to { chain, rpcClient ->
-            EthereumPosGrpcUpstream(
-                id,
-                hash,
-                role,
-                chain,
-                client,
-                rpcClient,
-                nodeRating,
-                labels,
-                chainsConfig.resolve(chain.chainName),
-                headScheduler,
-            )
-        },
-        BlockchainType.BITCOIN to { chain, rpcClient ->
-            BitcoinGrpcUpstream(id, role, chain, client, rpcClient, labels, chainsConfig.resolve(chain.chainCode), headScheduler)
-        },
-    )
-
    private fun getOrCreate(chain: Chain): UpstreamChangeEvent {
        val metrics = makeMetrics(chain)
-        val creator = creators.getValue(BlockchainType.from(chain))
+        val creator = if (BlockchainType.from(chain) != BITCOIN) {
+            { ch: Chain, rpcClient: JsonRpcGrpcClient ->
+                GenericGrpcUpstream(
+                    id,
+                    hash,
+                    role,
+                    ch,
+                    client,
+                    rpcClient,
+                    nodeRating,
+                    labels,
+                    chainsConfig.resolve(chain.chainName),
+                    headScheduler,
+                )
+            }
+        } else {
+            { ch: Chain, rpcClient: JsonRpcGrpcClient ->
+                BitcoinGrpcUpstream(
+                    id,
+                    role,
+                    chain,
+                    client,
+                    rpcClient,
+                    labels,
+                    chainsConfig.resolve(chain.chainCode),
+                    headScheduler,
+                )
+            }
+        }
        return getOrCreate(chain, metrics, creator)
    }

@@ -315,7 +310,7 @@ class GrpcUpstreams(
                val rpcClient = JsonRpcGrpcClient(client, chain, metrics)
                val created = creator(chain, rpcClient)
                known[chain] = created
-                if (created is Lifecycle) created.start()
+                created.start()
                UpstreamChangeEvent(chain, created, UpstreamChangeEvent.ChangeType.ADDED)
            } else {
                UpstreamChangeEvent(chain, current, UpstreamChangeEvent.ChangeType.REVALIDATED)
--- a/src/main/kotlin/io/emeraldpay/dshackle/upstream/starknet/StarknetChainSpecific.kt
+++ b/src/main/kotlin/io/emeraldpay/dshackle/upstream/starknet/StarknetChainSpecific.kt
@@ -2,12 +2,32 @@ package io.emeraldpay.dshackle.upstream.starknet

 import com.fasterxml.jackson.annotation.JsonIgnoreProperties
 import com.fasterxml.jackson.annotation.JsonProperty
+import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.Global
+import io.emeraldpay.dshackle.config.ChainsConfig.ChainConfig
 import io.emeraldpay.dshackle.data.BlockContainer
 import io.emeraldpay.dshackle.data.BlockId
+import io.emeraldpay.dshackle.foundation.ChainOptions.Options
+import io.emeraldpay.dshackle.reader.JsonRpcReader
+import io.emeraldpay.dshackle.upstream.CachingReader
+import io.emeraldpay.dshackle.upstream.EgressSubscription
+import io.emeraldpay.dshackle.upstream.EmptyEgressSubscription
+import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.LabelsDetector
+import io.emeraldpay.dshackle.upstream.Multistream
+import io.emeraldpay.dshackle.upstream.NoopCachingReader
+import io.emeraldpay.dshackle.upstream.Upstream
+import io.emeraldpay.dshackle.upstream.UpstreamValidator
+import io.emeraldpay.dshackle.upstream.calls.CallMethods
+import io.emeraldpay.dshackle.upstream.generic.CachingReaderBuilder
 import io.emeraldpay.dshackle.upstream.generic.ChainSpecific
+import io.emeraldpay.dshackle.upstream.generic.GenericUpstream
+import io.emeraldpay.dshackle.upstream.generic.LocalReader
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import org.springframework.cloud.sleuth.Tracer
+import reactor.core.publisher.Mono
+import reactor.core.scheduler.Scheduler
 import java.math.BigInteger
 import java.time.Instant

@@ -30,7 +50,41 @@ object StarknetChainSpecific : ChainSpecific {
        )
    }

-    override fun latestBlockRequest(): JsonRpcRequest = JsonRpcRequest("starknet_getBlockWithTxHashes", listOf("latest"))
+    override fun latestBlockRequest(): JsonRpcRequest =
+        JsonRpcRequest("starknet_getBlockWithTxHashes", listOf("latest"))
+
+    override fun localReaderBuilder(
+        cachingReader: CachingReader,
+        methods: CallMethods,
+        head: Head,
+    ): Mono<JsonRpcReader> {
+        return Mono.just(LocalReader(methods))
+    }
+
+    override fun subscriptionBuilder(headScheduler: Scheduler): (Multistream) -> EgressSubscription {
+        return { _ -> EmptyEgressSubscription }
+    }
+
+    override fun makeCachingReaderBuilder(tracer: Tracer): CachingReaderBuilder {
+        return { _, _, _ -> NoopCachingReader }
+    }
+
+    override fun validator(
+        chain: Chain,
+        upstream: Upstream,
+        options: Options,
+        config: ChainConfig,
+    ): UpstreamValidator? {
+        return null
+    }
+
+    override fun labelDetector(chain: Chain, reader: JsonRpcReader): LabelsDetector? {
+        return null
+    }
+
+    override fun subscriptionTopics(upstream: GenericUpstream): List<String> {
+        return emptyList()
+    }
 }

@JsonIgnoreProperties(ignoreUnknown = true)
--- a/src/test/groovy/io/emeraldpay/dshackle/config/CacheConfigReaderSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/config/CacheConfigReaderSpec.groovy
@@ -47,14 +47,4 @@ class CacheConfigReaderSpec extends Specification {
        //later may be not null if we support something else besides Redis
        act == null
    }
-
-    def "Local read disabled"() {
-        setup:
-        def config = this.class.getClassLoader().getResourceAsStream("cache-local-router-disabled.yaml")
-        when:
-        def act = reader.read(config)
-
-        then:
-        !act.requestsCacheEnabled
-    }
 }
--- a/src/test/groovy/io/emeraldpay/dshackle/rpc/NativeCallSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/rpc/NativeCallSpec.groovy
@@ -54,7 +54,7 @@ class NativeCallSpec extends Specification {

    ObjectMapper objectMapper = Global.objectMapper

-    def nativeCall(MultistreamHolder upstreams = null, ResponseSigner signer = null, Boolean enableCache = true, Boolean passthrough = false) {
+    def nativeCall(MultistreamHolder upstreams = null, ResponseSigner signer = null, Boolean passthrough = false) {

        if (upstreams == null) {
            upstreams = Stub(MultistreamHolder)
@@ -65,7 +65,6 @@ class NativeCallSpec extends Specification {

        def config = new MainConfig()
        def cacheConfig = new CacheConfig()
-        cacheConfig.requestsCacheEnabled = enableCache
        config.cache = cacheConfig
        config.passthrough = passthrough

@@ -77,7 +76,7 @@ class NativeCallSpec extends Specification {
            1 * read(new JsonRpcRequest("eth_test", [])) >> Mono.just(new JsonRpcResponse("1".bytes, null))
        }
        def upstream = Mock(Multistream) {
-            1 * getLocalReader(_) >> Mono.just(routedApi)
+            1 * getLocalReader() >> Mono.just(routedApi)
        }

        def nativeCall = nativeCall()
@@ -98,7 +97,7 @@ class NativeCallSpec extends Specification {
            1 * read(new JsonRpcRequest("eth_test", [])) >> Mono.error(new RpcException(RpcResponseError.CODE_METHOD_NOT_EXIST, "Test message"))
        }
        def upstream = Mock(Multistream) {
-            1 * getLocalReader(_) >> Mono.just(routedApi)
+            1 * getLocalReader() >> Mono.just(routedApi)
        }

        def nativeCall = nativeCall()
--- a/src/test/groovy/io/emeraldpay/dshackle/rpc/NativeSubscribeSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/rpc/NativeSubscribeSpec.groovy
@@ -21,7 +21,7 @@ import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.test.MultistreamHolderMock
 import io.emeraldpay.dshackle.upstream.Selector
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumEgressSubscription
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumPosMultiStream
+import io.emeraldpay.dshackle.upstream.generic.GenericMultistream
 import io.emeraldpay.dshackle.upstream.signature.NoSigner
 import reactor.core.publisher.Flux
 import reactor.test.StepVerifier
@@ -42,7 +42,7 @@ class NativeSubscribeSpec extends Specification {
        def subscribe = Mock(EthereumEgressSubscription) {
            1 * it.subscribe("newHeads", null, _ as Selector.AnyLabelMatcher) >> Flux.just("{}")
        }
-        def up = Mock(EthereumPosMultiStream) {
+        def up = Mock(GenericMultistream) {
            1 * it.tryProxySubscribe(_ as Selector.AnyLabelMatcher, call) >> null
            1 * it.getEgressSubscription() >> subscribe
        }
@@ -81,7 +81,7 @@ class NativeSubscribeSpec extends Specification {
                ok
            }, _ as Selector.AnyLabelMatcher) >> Flux.just("{}")
        }
-        def up = Mock(EthereumPosMultiStream) {
+        def up = Mock(GenericMultistream) {
            1 * it.tryProxySubscribe(_ as Selector.AnyLabelMatcher, call) >> null
            1 * it.getEgressSubscription() >> subscribe
        }
@@ -104,7 +104,7 @@ class NativeSubscribeSpec extends Specification {
                .setChainValue(Chain.ETHEREUM__MAINNET.id)
                .setMethod("newHeads")
                .build()
-        def up = Mock(EthereumPosMultiStream) {
+        def up = Mock(GenericMultistream) {
            1 * it.tryProxySubscribe(_ as Selector.AnyLabelMatcher, call) >> Flux.just("{}")
            0 * it.getEgressSubscription()
        }
--- a/src/test/groovy/io/emeraldpay/dshackle/rpc/StreamHeadSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/rpc/StreamHeadSpec.groovy
@@ -16,17 +16,15 @@
 */
 package io.emeraldpay.dshackle.rpc

-import com.fasterxml.jackson.databind.ObjectMapper
 import com.google.protobuf.ByteString
 import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.api.proto.Common
 import io.emeraldpay.dshackle.Chain
-import io.emeraldpay.dshackle.Global
 import io.emeraldpay.dshackle.data.BlockContainer
-import io.emeraldpay.dshackle.test.EthereumPosRpcUpstreamMock
+import io.emeraldpay.dshackle.upstream.generic.GenericUpstream
+import io.emeraldpay.dshackle.test.GenericUpstreamMock
 import io.emeraldpay.dshackle.test.MultistreamHolderMock
 import io.emeraldpay.dshackle.test.TestingCommons
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumLikeRpcUpstream
 import io.emeraldpay.dshackle.upstream.ethereum.json.BlockJson
 import io.emeraldpay.etherjar.domain.BlockHash
 import io.emeraldpay.etherjar.rpc.json.TransactionRefJson
@@ -39,11 +37,9 @@ import java.time.Instant

 class StreamHeadSpec extends Specification {

-    ObjectMapper objectMapper = Global.objectMapper
-
    def "Errors on unavailable chain"() {
        setup:
-        def upstreams = new MultistreamHolderMock(Chain.ETHEREUM__MAINNET, Stub(EthereumLikeRpcUpstream))
+        def upstreams = new MultistreamHolderMock(Chain.ETHEREUM__MAINNET, Stub(GenericUpstream))
        def streamHead = new StreamHead(upstreams)
        when:
        def flux = streamHead.add(
@@ -80,7 +76,7 @@ class StreamHeadSpec extends Specification {
                .build()
        }

-        def upstream = new EthereumPosRpcUpstreamMock(Chain.ETHEREUM__MAINNET, TestingCommons.api())
+        def upstream = new GenericUpstreamMock(Chain.ETHEREUM__MAINNET, TestingCommons.api())
        def upstreams = new MultistreamHolderMock(Chain.ETHEREUM__MAINNET, upstream)
        def streamHead = new StreamHead(upstreams)
        when:
--- a/src/test/groovy/io/emeraldpay/dshackle/test/EthereumRpcUpstreamMock.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/test/EthereumRpcUpstreamMock.groovy
@@ -1,87 +0,0 @@
-/**
- * Copyright (c) 2019 ETCDEV GmbH
- * Copyright (c) 2020 EmeraldPay, Inc
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.test
-
-import io.emeraldpay.dshackle.Chain
-import io.emeraldpay.dshackle.config.ChainsConfig
-import io.emeraldpay.dshackle.config.UpstreamsConfig
-import io.emeraldpay.dshackle.data.BlockContainer
-import io.emeraldpay.dshackle.reader.Reader
-import io.emeraldpay.dshackle.startup.QuorumForLabels
-import io.emeraldpay.dshackle.upstream.UpstreamAvailability
-import io.emeraldpay.dshackle.upstream.calls.*
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumLikeRpcUpstream
-import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
-import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
-import org.jetbrains.annotations.NotNull
-import io.emeraldpay.dshackle.foundation.ChainOptions
-import org.reactivestreams.Publisher
-
-class EthereumRpcUpstreamMock extends EthereumLikeRpcUpstream {
-    EthereumHeadMock ethereumHeadMock
-
-
-    static CallMethods allMethods() {
-        new AggregatedCallMethods([
-                new DefaultEthereumMethods(Chain.ETHEREUM__MAINNET),
-                new DefaultBitcoinMethods(),
-                new DirectCallMethods(["eth_test"])
-        ])
-    }
-
-    EthereumRpcUpstreamMock(@NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api) {
-        this(chain, api, allMethods())
-    }
-
-    EthereumRpcUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api) {
-        this(id, chain, api, allMethods())
-    }
-
-    EthereumRpcUpstreamMock(@NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods methods) {
-        this("test", chain, api, methods)
-    }
-
-    EthereumRpcUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods methods) {
-        super(id, id.hashCode().byteValue(), chain,
-                ChainOptions.PartialOptions.getDefaults().buildOptions(),
-                UpstreamsConfig.UpstreamRole.PRIMARY,
-                methods,
-                new QuorumForLabels.QuorumItem(1, new UpstreamsConfig.Labels()),
-                new ConnectorFactoryMock(api, new EthereumHeadMock()),
-                ChainsConfig.ChainConfig.default(),
-                false,
-                null
-        )
-        this.ethereumHeadMock = this.getHead() as EthereumHeadMock
-        setLag(0)
-        setStatus(UpstreamAvailability.OK)
-        start()
-    }
-
-    void nextBlock(BlockContainer block) {
-        this.ethereumHeadMock.nextBlock(block)
-    }
-
-    void setBlocks(Publisher<BlockContainer> blocks) {
-        this.ethereumHeadMock.predefined = blocks
-    }
-
-    @Override
-    String toString() {
-        return "Upstream mock ${getId()}"
-    }
-}
--- a/src/test/groovy/io/emeraldpay/dshackle/test/GenericConnectorMock.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/test/GenericConnectorMock.groovy
@@ -2,7 +2,7 @@ package io.emeraldpay.dshackle.test

 import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.upstream.Head
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumIngressSubscription
+import io.emeraldpay.dshackle.upstream.IngressSubscription
 import io.emeraldpay.dshackle.upstream.ethereum.NoEthereumIngressSubscription
 import io.emeraldpay.dshackle.upstream.generic.connectors.GenericConnector
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
@@ -47,7 +47,7 @@ class GenericConnectorMock implements GenericConnector {
    }

    @Override
-    EthereumIngressSubscription getIngressSubscription() {
+    IngressSubscription getIngressSubscription() {
        return NoEthereumIngressSubscription.DEFAULT
    }
 }
--- a/src/test/groovy/io/emeraldpay/dshackle/test/EthereumPosRpcUpstreamMock.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/test/EthereumPosRpcUpstreamMock.groovy
@@ -24,14 +24,14 @@ import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.startup.QuorumForLabels
 import io.emeraldpay.dshackle.upstream.UpstreamAvailability
 import io.emeraldpay.dshackle.upstream.calls.*
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumLikeRpcUpstream
+import io.emeraldpay.dshackle.upstream.generic.GenericUpstream
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
 import org.jetbrains.annotations.NotNull
 import org.reactivestreams.Publisher
 import io.emeraldpay.dshackle.foundation.ChainOptions

-class EthereumPosRpcUpstreamMock extends EthereumLikeRpcUpstream {
+class GenericUpstreamMock extends GenericUpstream {
    EthereumHeadMock ethereumHeadMock

    static CallMethods allMethods() {
@@ -42,36 +42,40 @@ class EthereumPosRpcUpstreamMock extends EthereumLikeRpcUpstream {
        ])
    }

-    EthereumPosRpcUpstreamMock(@NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api) {
+    GenericUpstreamMock(@NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api) {
        this(chain, api, allMethods())
    }

-    EthereumPosRpcUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, Map<String, String> labels) {
+    GenericUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, Map<String, String> labels) {
        this(id, chain, api, allMethods(), labels)
    }

-    EthereumPosRpcUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api) {
+    GenericUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api) {
        this(id, chain, api, allMethods())
    }

-    EthereumPosRpcUpstreamMock(@NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods methods) {
+    GenericUpstreamMock(@NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods methods) {
        this("test", chain, api, methods)
    }

-    EthereumPosRpcUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods methods) {
+    GenericUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods methods) {
        this(id, chain, api, methods, Collections.<String, String>emptyMap())
    }

-    EthereumPosRpcUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods methods, Map<String, String> labels) {
-        super(id, (byte)id.hashCode(), chain,
+    GenericUpstreamMock(@NotNull String id, @NotNull Chain chain, @NotNull Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods methods, Map<String, String> labels) {
+        super(id,
+                chain,
+                (byte)id.hashCode(),
                getOpts(),
                UpstreamsConfig.UpstreamRole.PRIMARY,
                methods,
                new QuorumForLabels.QuorumItem(1, UpstreamsConfig.Labels.fromMap(labels)),
-                new ConnectorFactoryMock(api, new EthereumHeadMock()),
                ChainConfig.default(),
-                true,
-                null
+                new ConnectorFactoryMock(api, new EthereumHeadMock()),
+                null,
+                io.emeraldpay.dshackle.upstream.starknet.StarknetChainSpecific.INSTANCE.&validator,
+                io.emeraldpay.dshackle.upstream.starknet.StarknetChainSpecific.INSTANCE.&labelDetector,
+                io.emeraldpay.dshackle.upstream.starknet.StarknetChainSpecific.INSTANCE.&subscriptionTopics,
        )
        this.ethereumHeadMock = this.getHead() as EthereumHeadMock
        setLag(0)
--- a/src/test/groovy/io/emeraldpay/dshackle/test/MultistreamHolderMock.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/test/MultistreamHolderMock.groovy
@@ -20,13 +20,13 @@ import io.emeraldpay.dshackle.BlockchainType
 import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.cache.Caches
 import io.emeraldpay.dshackle.upstream.*
+import io.emeraldpay.dshackle.upstream.generic.*
 import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinMultistream
 import io.emeraldpay.dshackle.upstream.bitcoin.BitcoinRpcUpstream
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.dshackle.upstream.calls.DefaultEthereumMethods
 import io.emeraldpay.dshackle.upstream.ethereum.EthereumCachingReader
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumLikeRpcUpstream
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumPosMultiStream
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumChainSpecific
 import org.jetbrains.annotations.NotNull
 import org.springframework.cloud.sleuth.brave.bridge.BraveTracer
 import reactor.core.scheduler.Schedulers
@@ -42,13 +42,16 @@ class MultistreamHolderMock implements MultistreamHolder {

    Multistream addUpstream(@NotNull Chain chain, @NotNull Upstream up) {
        if (!upstreams.containsKey(chain)) {
-            if (BlockchainType.from(chain) == BlockchainType.EVM_POS) {
-                if (up instanceof EthereumPosMultiStream) {
+            if (BlockchainType.from(chain) == BlockchainType.ETHEREUM) {
+                if (up instanceof GenericMultistream) {
                    upstreams[chain] = up
-                } else if (up instanceof EthereumLikeRpcUpstream) {
-                    upstreams[chain] = new EthereumPosMultiStream(
-                            chain, [up as EthereumLikeRpcUpstream], Caches.default(),
-                            Schedulers.boundedElastic(), TestingCommons.tracerMock()
+                } else if (up instanceof GenericUpstream) {
+                    upstreams[chain] = new GenericMultistream(
+                            chain, [up as GenericUpstream], Caches.default(),
+                            Schedulers.boundedElastic(),
+                            EthereumChainSpecific.INSTANCE.makeCachingReaderBuilder(TestingCommons.tracerMock()),
+                            EthereumChainSpecific.INSTANCE.&localReaderBuilder,
+                            io.emeraldpay.dshackle.upstream.starknet.StarknetChainSpecific.INSTANCE.subscriptionBuilder(Schedulers.boundedElastic())
                    )
                } else {
                    throw new IllegalArgumentException("Unsupported upstream type ${up.class}")
@@ -90,21 +93,24 @@ class MultistreamHolderMock implements MultistreamHolder {
        return upstreams.values().toList()
    }

-    static class EthereumMultistreamMock extends EthereumPosMultiStream {
+    static class EthereumMultistreamMock extends GenericMultistream {

        EthereumCachingReader customReader = null
        CallMethods customMethods = null
        Head customHead = null

-        EthereumMultistreamMock(@NotNull Chain chain, @NotNull List<EthereumLikeRpcUpstream> upstreams, @NotNull Caches caches) {
-            super(chain, upstreams, caches, Schedulers.boundedElastic(), new BraveTracer(null, null, null))
+        EthereumMultistreamMock(@NotNull Chain chain, @NotNull List<GenericUpstream> upstreams, @NotNull Caches caches) {
+            super(chain, upstreams, caches, Schedulers.boundedElastic(),
+                    EthereumChainSpecific.INSTANCE.makeCachingReaderBuilder(new BraveTracer(null, null, null)),
+                    EthereumChainSpecific.INSTANCE.&localReaderBuilder,
+                    EthereumChainSpecific.INSTANCE.subscriptionBuilder(Schedulers.boundedElastic()))
        }

-        EthereumMultistreamMock(@NotNull Chain chain, @NotNull List<EthereumLikeRpcUpstream> upstreams) {
+        EthereumMultistreamMock(@NotNull Chain chain, @NotNull List<GenericUpstream> upstreams) {
            this(chain, upstreams, Caches.default())
        }

-        EthereumMultistreamMock(@NotNull Chain chain, @NotNull EthereumLikeRpcUpstream upstream) {
+        EthereumMultistreamMock(@NotNull Chain chain, @NotNull GenericUpstream upstream) {
            this(chain, [upstream])
        }

--- a/src/test/groovy/io/emeraldpay/dshackle/test/TestingCommons.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/test/TestingCommons.groovy
@@ -28,10 +28,10 @@ import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.upstream.Multistream
 import io.emeraldpay.dshackle.upstream.calls.CallMethods
 import io.emeraldpay.dshackle.upstream.calls.DirectCallMethods
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumPosMultiStream
+import io.emeraldpay.dshackle.upstream.generic.GenericMultistream
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumChainSpecific
 import io.emeraldpay.etherjar.domain.BlockHash
 import io.emeraldpay.dshackle.upstream.ethereum.json.BlockJson
 import io.emeraldpay.etherjar.domain.TransactionId
@@ -54,44 +54,49 @@ class TestingCommons {
        return new TracerMock(null, null, null)
    }

-    static EthereumPosRpcUpstreamMock upstream() {
-        return new EthereumPosRpcUpstreamMock(Chain.ETHEREUM__MAINNET, api())
+    static GenericUpstreamMock upstream() {
+        return new GenericUpstreamMock(Chain.ETHEREUM__MAINNET, api())
    }

-    static EthereumPosRpcUpstreamMock upstream(String id) {
-        return new EthereumPosRpcUpstreamMock(id, Chain.ETHEREUM__MAINNET, api())
+    static GenericUpstreamMock upstream(String id) {
+        return new GenericUpstreamMock(id, Chain.ETHEREUM__MAINNET, api())
    }

-    static EthereumPosRpcUpstreamMock upstream(String id, String provider) {
-        return new EthereumPosRpcUpstreamMock(id, Chain.ETHEREUM__MAINNET, api(), Collections.singletonMap("provider", provider))
+    static GenericUpstreamMock upstream(String id, String provider) {
+        return new GenericUpstreamMock(id, Chain.ETHEREUM__MAINNET, api(), Collections.singletonMap("provider", provider))
    }

-    static EthereumPosRpcUpstreamMock upstream(String id, Reader<JsonRpcRequest, JsonRpcResponse> api) {
-        return new EthereumPosRpcUpstreamMock(id, Chain.ETHEREUM__MAINNET, api)
+    static GenericUpstreamMock upstream(String id, Reader<JsonRpcRequest, JsonRpcResponse> api) {
+        return new GenericUpstreamMock(id, Chain.ETHEREUM__MAINNET, api)
    }

-    static EthereumPosRpcUpstreamMock upstream(Reader<JsonRpcRequest, JsonRpcResponse> api) {
-        return new EthereumPosRpcUpstreamMock(Chain.ETHEREUM__MAINNET, api)
+    static GenericUpstreamMock upstream(Reader<JsonRpcRequest, JsonRpcResponse> api) {
+        return new GenericUpstreamMock(Chain.ETHEREUM__MAINNET, api)
    }

-    static EthereumPosRpcUpstreamMock upstream(Reader<JsonRpcRequest, JsonRpcResponse> api, String method) {
+    static GenericUpstreamMock upstream(Reader<JsonRpcRequest, JsonRpcResponse> api, String method) {
        return upstream(api, [method])
    }

-    static EthereumPosRpcUpstreamMock upstream(Reader<JsonRpcRequest, JsonRpcResponse> api, List<String> methods) {
-        return new EthereumPosRpcUpstreamMock(Chain.ETHEREUM__MAINNET, api, new DirectCallMethods(methods))
+    static GenericUpstreamMock upstream(Reader<JsonRpcRequest, JsonRpcResponse> api, List<String> methods) {
+        return new GenericUpstreamMock(Chain.ETHEREUM__MAINNET, api, new DirectCallMethods(methods))
    }

-    static EthereumPosRpcUpstreamMock upstream(Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods callMethods) {
-        return new EthereumPosRpcUpstreamMock(Chain.ETHEREUM__MAINNET, api, callMethods)
+    static GenericUpstreamMock upstream(Reader<JsonRpcRequest, JsonRpcResponse> api, CallMethods callMethods) {
+        return new GenericUpstreamMock(Chain.ETHEREUM__MAINNET, api, callMethods)
    }

    static Multistream multistream(Reader<JsonRpcRequest, JsonRpcResponse> api) {
        return multistream(upstream(api))
    }

-    static Multistream multistream(EthereumPosRpcUpstreamMock up) {
-        return new EthereumPosMultiStream(Chain.ETHEREUM__MAINNET, [up], Caches.default(), Schedulers.boundedElastic(), tracerMock()).tap {
+    static Multistream multistream(GenericUpstreamMock up) {
+        return new GenericMultistream(Chain.ETHEREUM__MAINNET, [up], Caches.default(),
+                Schedulers.boundedElastic(),
+                EthereumChainSpecific.INSTANCE.makeCachingReaderBuilder(tracerMock()),
+                EthereumChainSpecific.INSTANCE.&localReaderBuilder,
+                EthereumChainSpecific.INSTANCE.subscriptionBuilder(Schedulers.boundedElastic()),
+        ).tap {
            start()
        }
    }
@@ -112,11 +117,17 @@ class TestingCommons {
    }

    static Multistream multistreamWithoutUpstreams(Chain chain) {
-        return new EthereumPosMultiStream(chain, [], emptyCaches().getCaches(chain), Schedulers.boundedElastic(), tracerMock())
+        return new GenericMultistream(chain, [], emptyCaches().getCaches(chain), Schedulers.boundedElastic(),
+                EthereumChainSpecific.INSTANCE.makeCachingReaderBuilder(tracerMock()),
+                EthereumChainSpecific.INSTANCE.&localReaderBuilder,
+                EthereumChainSpecific.INSTANCE.subscriptionBuilder(Schedulers.boundedElastic()))
    }

    static Multistream multistreamClassicWithoutUpstreams(Chain chain) {
-        return new EthereumMultistream(chain, [], emptyCaches().getCaches(chain), Schedulers.boundedElastic(), tracerMock())
+        return new GenericMultistream(chain, [], emptyCaches().getCaches(chain), Schedulers.boundedElastic(),
+                EthereumChainSpecific.INSTANCE.makeCachingReaderBuilder(tracerMock()),
+                EthereumChainSpecific.INSTANCE.&localReaderBuilder,
+                EthereumChainSpecific.INSTANCE.subscriptionBuilder(Schedulers.boundedElastic()))
    }

    static FileResolver fileResolver() {
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/AbstractChainFeesSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/AbstractChainFeesSpec.groovy
@@ -1,253 +0,0 @@
-package io.emeraldpay.dshackle.upstream
-
-import kotlin.jvm.functions.Function1
-import org.jetbrains.annotations.NotNull
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import spock.lang.Specification
-
-import java.time.Duration
-import java.util.function.Function
-
-class AbstractChainFeesSpec extends Specification {
-
-    Function<List<String>, List<String>> extractTx = { it }
-
-    def "Iterates N last blocks"() {
-        setup:
-        def ups = Mock(Multistream) {
-            1 * getHead() >> Mock(Head) {
-                1 * it.getCurrentHeight() >> 234
-            }
-        }
-        def fees = new TestChainFees(5, ups, Stub(Function1))
-        when:
-        def act = fees.usingBlocks(3).collectList().block(Duration.ofSeconds(1)).toSorted()
-        then:
-        act == [232L, 233L, 234L]
-    }
-
-    def "Limits iteration to configured"() {
-        setup:
-        def ups = Mock(Multistream) {
-            1 * getHead() >> Mock(Head) {
-                1 * it.getCurrentHeight() >> 234
-            }
-        }
-        def fees = new TestChainFees(3, ups, Stub(Function1))
-        when:
-        def act = fees.usingBlocks(5).collectList().block(Duration.ofSeconds(1)).toSorted()
-        then:
-        act == [232L, 233L, 234L]
-    }
-
-    def "TxAtPos 0 for empty list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtPos<List<String>, String>(extractTx, 0)
-
-        when:
-        def act = txAt.get([])
-
-        then:
-        act == null
-    }
-
-    def "TxAtPos 0 for single item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtPos<List<String>, String>(extractTx, 0)
-
-        when:
-        def act = txAt.get(["t_1"])
-
-        then:
-        act == "t_1"
-    }
-
-    def "TxAtPos 0 for many item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtPos<List<String>, String>(extractTx, 0)
-
-        when:
-        def act = txAt.get(["t_1", "t_2", "t_3"])
-
-        then:
-        act == "t_3"
-    }
-
-    def "TxAtPos 1 for many item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtPos<List<String>, String>(extractTx, 1)
-
-        when:
-        def act = txAt.get(["t_1", "t_2", "t_3"])
-
-        then:
-        act == "t_2"
-    }
-
-    def "TxAtPos 2 for many item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtPos<List<String>, String>(extractTx, 2)
-
-        when:
-        def act = txAt.get(["t_1", "t_2", "t_3"])
-
-        then:
-        act == "t_1"
-    }
-
-    def "TxAtPos 5 for 3 item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtPos<List<String>, String>(extractTx, 5)
-
-        when:
-        def act = txAt.get(["t_1", "t_2", "t_3"])
-
-        then:
-        act == "t_1"
-    }
-
-    def "TxAtBottom for empty list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtBottom<List<String>, String>(extractTx)
-
-        when:
-        def act = txAt.get([])
-
-        then:
-        act == null
-    }
-
-    def "TxAtBottom for single item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtBottom<List<String>, String>(extractTx)
-
-        when:
-        def act = txAt.get(["t_1"])
-
-        then:
-        act == "t_1"
-    }
-
-    def "TxAtBottom for multi item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtBottom<List<String>, String>(extractTx)
-
-        when:
-        def act = txAt.get(["t_1", "t_2", "t_3"])
-
-        then:
-        act == "t_3"
-    }
-
-    def "TxAtTop for empty list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtTop<List<String>, String>(extractTx)
-
-        when:
-        def act = txAt.get([])
-
-        then:
-        act == null
-    }
-
-    def "TxAtTop for single item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtTop<List<String>, String>(extractTx)
-
-        when:
-        def act = txAt.get(["t_1"])
-
-        then:
-        act == "t_1"
-    }
-
-    def "TxAtTop for multi item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtTop<List<String>, String>(extractTx)
-
-        when:
-        def act = txAt.get(["t_1", "t_2", "t_3"])
-
-        then:
-        act == "t_1"
-    }
-
-    def "TxAtMiddle for empty list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtMiddle<List<String>, String>(extractTx)
-
-        when:
-        def act = txAt.get([])
-
-        then:
-        act == null
-    }
-
-    def "TxAtMiddle for single item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtMiddle<List<String>, String>(extractTx)
-
-        when:
-        def act = txAt.get(["t_1"])
-
-        then:
-        act == "t_1"
-    }
-
-    def "TxAtMiddle for 3 item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtMiddle<List<String>, String>(extractTx)
-
-        when:
-        def act = txAt.get(["t_1", "t_2", "t_3"])
-
-        then:
-        act == "t_2"
-    }
-
-    def "TxAtMiddle for 4 item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtMiddle<List<String>, String>(extractTx)
-
-        when:
-        def act = txAt.get(["t_1", "t_2", "t_3", "t_4"])
-
-        then:
-        act == "t_2" || act == "t_3"
-    }
-
-    def "TxAtMiddle for 5 item list"() {
-        setup:
-        def txAt = new AbstractChainFees.TxAtMiddle<List<String>, String>(extractTx)
-
-        when:
-        def act = txAt.get(["t_1", "t_2", "t_3", "t_4", "t_5"])
-
-        then:
-        act == "t_3"
-    }
-
-    class TestChainFees extends AbstractChainFees {
-
-        TestChainFees(int heightLimit, @NotNull Multistream upstreams, @NotNull Function1 extractTx) {
-            super(heightLimit, upstreams, extractTx)
-        }
-
-        @Override
-        Mono readFeesAt(long height, @NotNull TxAt selector) {
-            return null
-        }
-
-        @Override
-        Function<Flux, Mono> feeAggregation(@NotNull Mode mode) {
-            return null
-        }
-
-        @Override
-        Function getResponseBuilder() {
-            return null
-        }
-    }
-
-}
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/CurrentMultistreamHolderSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/CurrentMultistreamHolderSpec.groovy
@@ -17,8 +17,7 @@ package io.emeraldpay.dshackle.upstream

 import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.startup.UpstreamChangeEvent
-import io.emeraldpay.dshackle.test.EthereumPosRpcUpstreamMock
-import io.emeraldpay.dshackle.test.EthereumRpcUpstreamMock
+import io.emeraldpay.dshackle.test.GenericUpstreamMock
 import io.emeraldpay.dshackle.test.TestingCommons
 import spock.lang.Specification

@@ -27,7 +26,7 @@ class CurrentMultistreamHolderSpec extends Specification {
    def "add upstream"() {
        setup:
        def current = new CurrentMultistreamHolder(TestingCommons.defaultMultistreams())
-        def up = new EthereumPosRpcUpstreamMock("test", Chain.ETHEREUM__MAINNET, TestingCommons.api())
+        def up = new GenericUpstreamMock("test", Chain.ETHEREUM__MAINNET, TestingCommons.api())
        when:
        current.getUpstream(Chain.ETHEREUM__MAINNET).onUpstreamChange(new UpstreamChangeEvent(Chain.ETHEREUM__MAINNET, up, UpstreamChangeEvent.ChangeType.ADDED))
        then:
@@ -38,9 +37,9 @@ class CurrentMultistreamHolderSpec extends Specification {
    def "add multiple upstreams"() {
        setup:
        def current = new CurrentMultistreamHolder(TestingCommons.defaultMultistreams())
-        def up1 = new EthereumPosRpcUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api())
-        def up2 = new EthereumRpcUpstreamMock("test2", Chain.ETHEREUM_CLASSIC__MAINNET, TestingCommons.api())
-        def up3 = new EthereumPosRpcUpstreamMock("test3", Chain.ETHEREUM__MAINNET, TestingCommons.api())
+        def up1 = new GenericUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api())
+        def up2 = new GenericUpstreamMock("test2", Chain.ETHEREUM_CLASSIC__MAINNET, TestingCommons.api())
+        def up3 = new GenericUpstreamMock("test3", Chain.ETHEREUM__MAINNET, TestingCommons.api())
        when:
        current.getUpstream(Chain.ETHEREUM__MAINNET).onUpstreamChange(new UpstreamChangeEvent(Chain.ETHEREUM__MAINNET, up1, UpstreamChangeEvent.ChangeType.ADDED))
        current.getUpstream(Chain.ETHEREUM_CLASSIC__MAINNET).onUpstreamChange(new UpstreamChangeEvent(Chain.ETHEREUM_CLASSIC__MAINNET, up2, UpstreamChangeEvent.ChangeType.ADDED))
@@ -55,10 +54,10 @@ class CurrentMultistreamHolderSpec extends Specification {
    def "remove upstream"() {
        setup:
        def current = new CurrentMultistreamHolder(TestingCommons.defaultMultistreams())
-        def up1 = new EthereumPosRpcUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api())
-        def up2 = new EthereumRpcUpstreamMock("test2", Chain.ETHEREUM_CLASSIC__MAINNET, TestingCommons.api())
-        def up3 = new EthereumPosRpcUpstreamMock("test3", Chain.ETHEREUM__MAINNET, TestingCommons.api())
-        def up1_del = new EthereumPosRpcUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api())
+        def up1 = new GenericUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api())
+        def up2 = new GenericUpstreamMock("test2", Chain.ETHEREUM_CLASSIC__MAINNET, TestingCommons.api())
+        def up3 = new GenericUpstreamMock("test3", Chain.ETHEREUM__MAINNET, TestingCommons.api())
+        def up1_del = new GenericUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api())
        when:
        current.getUpstream(Chain.ETHEREUM__MAINNET).onUpstreamChange(new UpstreamChangeEvent(Chain.ETHEREUM__MAINNET, up1, UpstreamChangeEvent.ChangeType.ADDED))
        current.getUpstream(Chain.ETHEREUM_CLASSIC__MAINNET).onUpstreamChange(new UpstreamChangeEvent(Chain.ETHEREUM_CLASSIC__MAINNET, up2, UpstreamChangeEvent.ChangeType.ADDED))
@@ -73,7 +72,7 @@ class CurrentMultistreamHolderSpec extends Specification {
    def "available after adding"() {
        setup:
        def current = new CurrentMultistreamHolder(TestingCommons.defaultMultistreams())
-        def up1 = new EthereumPosRpcUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api())
+        def up1 = new GenericUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api())

        when:
        def act = current.isAvailable(Chain.ETHEREUM__MAINNET)
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/FilteredApisSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/FilteredApisSpec.groovy
@@ -24,7 +24,7 @@ import io.emeraldpay.dshackle.startup.QuorumForLabels
 import io.emeraldpay.dshackle.test.EthereumApiStub
 import io.emeraldpay.dshackle.test.TestingCommons
 import io.emeraldpay.dshackle.upstream.calls.DefaultEthereumMethods
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumLikeRpcUpstream
+import io.emeraldpay.dshackle.upstream.generic.GenericUpstream
 import io.emeraldpay.dshackle.upstream.generic.connectors.GenericConnectorFactory
 import io.emeraldpay.dshackle.upstream.forkchoice.MostWorkForkChoice
 import reactor.core.scheduler.Schedulers
@@ -44,13 +44,15 @@ class FilteredApisSpec extends Specification {
    def "Verifies labels"() {
        setup:
        def i = 0
-        List<EthereumLikeRpcUpstream> upstreams = [
+        def cs = io.emeraldpay.dshackle.upstream.starknet.StarknetChainSpecific.INSTANCE
+        List<GenericUpstream> upstreams = [
                [test: "foo"],
                [test: "bar"],
                [test: "foo", test2: "baz"],
                [test: "foo"],
                [test: "baz"]
        ].collect {
+
            def httpFactory = Mock(HttpFactory) {
                create(_, _) >> Stub(JsonRpcHttpReader)
            }
@@ -64,18 +66,20 @@ class FilteredApisSpec extends Specification {
                    Schedulers.boundedElastic(),
                    Duration.ofSeconds(12)
            )
-            new EthereumLikeRpcUpstream(
+            new GenericUpstream(
                    "test",
-                    (byte) 123,
                    Chain.ETHEREUM__MAINNET,
+                    (byte) 123,
                    new ChainOptions.PartialOptions().buildOptions(),
                    UpstreamsConfig.UpstreamRole.PRIMARY,
                    ethereumTargets,
                    new QuorumForLabels.QuorumItem(1, UpstreamsConfig.Labels.fromMap(it)),
-                    connectorFactory,
                    ChainsConfig.ChainConfig.default(),
-                    false,
-                    null
+                    connectorFactory,
+                    null,
+                    cs.&validator,
+                    cs.&labelDetector,
+                    cs.&subscriptionTopics,
            )
        }
        def matcher = new Selector.LabelMatcher("test", ["foo"])
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/MultistreamSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/MultistreamSpec.groovy
@@ -25,15 +25,17 @@ import io.emeraldpay.dshackle.data.BlockContainer
 import io.emeraldpay.dshackle.quorum.AlwaysQuorum
 import io.emeraldpay.dshackle.reader.Reader
 import io.emeraldpay.dshackle.startup.UpstreamChangeEvent
-import io.emeraldpay.dshackle.test.EthereumPosRpcUpstreamMock
+import io.emeraldpay.dshackle.test.GenericUpstreamMock
 import io.emeraldpay.dshackle.test.TestingCommons
 import io.emeraldpay.dshackle.upstream.calls.DirectCallMethods
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumLikeRpcUpstream
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumPosMultiStream
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumChainSpecific
+import io.emeraldpay.dshackle.upstream.generic.GenericUpstream
+import io.emeraldpay.dshackle.upstream.generic.GenericMultistream
 import io.emeraldpay.dshackle.upstream.ethereum.json.BlockJson
-import io.emeraldpay.dshackle.upstream.grpc.EthereumPosGrpcUpstream
+import io.emeraldpay.dshackle.upstream.grpc.GenericGrpcUpstream
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import io.emeraldpay.dshackle.upstream.starknet.StarknetChainSpecific
 import io.emeraldpay.etherjar.domain.BlockHash
 import io.emeraldpay.etherjar.rpc.json.TransactionRefJson
 import org.jetbrains.annotations.NotNull
@@ -51,9 +53,13 @@ class MultistreamSpec extends Specification {

    def "Aggregates methods"() {
        setup:
-        def up1 = new EthereumPosRpcUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test1", "eth_test2"]))
-        def up2 = new EthereumPosRpcUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test2", "eth_test3"]))
-        def aggr = new EthereumPosMultiStream(Chain.ETHEREUM__MAINNET, [up1, up2], Caches.default(), Schedulers.boundedElastic(), TestingCommons.tracerMock())
+        def up1 = new GenericUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test1", "eth_test2"]))
+        def up2 = new GenericUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test2", "eth_test3"]))
+        def aggr = new GenericMultistream(Chain.ETHEREUM__MAINNET, [up1, up2], Caches.default(),
+                Schedulers.boundedElastic(),
+                EthereumChainSpecific.INSTANCE.makeCachingReaderBuilder(TestingCommons.tracerMock()),
+                EthereumChainSpecific.INSTANCE.&localReaderBuilder,
+                EthereumChainSpecific.INSTANCE.subscriptionBuilder(Schedulers.boundedElastic()))
        when:
        aggr.onUpstreamsUpdated()
        def act = aggr.getMethods()
@@ -184,7 +190,11 @@ class MultistreamSpec extends Specification {
        def up1 = TestingCommons.upstream("test-1", "internal")
        def up2 = TestingCommons.upstream("test-2", "external")
        def up3 = TestingCommons.upstream("test-3", "external")
-        def multistream = new EthereumPosMultiStream(Chain.ETHEREUM__MAINNET, [up1, up2, up3], Caches.default(), Schedulers.boundedElastic(), TestingCommons.tracerMock())
+        def multistream = new GenericMultistream(Chain.ETHEREUM__MAINNET, [up1, up2, up3], Caches.default(),
+                Schedulers.boundedElastic(),
+                EthereumChainSpecific.INSTANCE.makeCachingReaderBuilder(TestingCommons.tracerMock()),
+                EthereumChainSpecific.INSTANCE.&localReaderBuilder,
+                EthereumChainSpecific.INSTANCE.subscriptionBuilder(Schedulers.boundedElastic()))

        expect:
        multistream.getHead(new Selector.LabelMatcher("provider", ["internal"])).is(up1.ethereumHeadMock)
@@ -205,14 +215,14 @@ class MultistreamSpec extends Specification {
                .setMethod("newHeads")
                .build()

-        def up1 = Mock(EthereumPosGrpcUpstream) {
+        def up1 = Mock(GenericGrpcUpstream) {
            1 * isGrpc() >> true
-            1 * getId() >> "internal"
+            _ * getId() >> "internal"
            1 * getLabels() >> [UpstreamsConfig.Labels.fromMap(Collections.singletonMap("provider", "internal"))]
            1 * proxySubscribe(call) >> Flux.just("{}")
        }
-        def up2 = Mock(EthereumPosGrpcUpstream) {
-            1 * getId() >> "external"
+        def up2 = Mock(GenericUpstream) {
+            _ * getId() >> "external"
            1 * getLabels() >> [UpstreamsConfig.Labels.fromMap(Collections.singletonMap("provider", "external"))]
        }
        def multiStream = new TestEthereumPosMultistream(Chain.ETHEREUM__MAINNET, [up1, up2], Caches.default())
@@ -235,9 +245,9 @@ class MultistreamSpec extends Specification {
                .setMethod("newHeads")
                .build()

-        def up2 = Mock(EthereumPosGrpcUpstream) {
+        def up2 = Mock(GenericUpstream) {
            1 * isGrpc() >> false
-            1 * getId() >> "2"
+            _ * getId() >> "2"
            1 * getLabels() >> [UpstreamsConfig.Labels.fromMap(Collections.singletonMap("provider", "internal"))]
        }
        def multiStream = new TestEthereumPosMultistream(Chain.ETHEREUM__MAINNET, [up2], Caches.default())
@@ -251,9 +261,13 @@ class MultistreamSpec extends Specification {

    def "Change ms methods based on upstream availability"() {
        setup:
-        def up1 = new EthereumPosRpcUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test1", "eth_test2", "eth_test3"]))
-        def up2 = new EthereumPosRpcUpstreamMock("test2", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test1", "eth_test2"]))
-        def ms = new EthereumPosMultiStream(Chain.ETHEREUM__MAINNET, new ArrayList<EthereumLikeRpcUpstream>(), Caches.default(), Schedulers.boundedElastic(), TestingCommons.tracerMock())
+        def up1 = new GenericUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test1", "eth_test2", "eth_test3"]))
+        def up2 = new GenericUpstreamMock("test2", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test1", "eth_test2"]))
+        def ms = new GenericMultistream(Chain.ETHEREUM__MAINNET, new ArrayList<GenericMultistream>(), Caches.default(),
+                Schedulers.boundedElastic(),
+                EthereumChainSpecific.INSTANCE.makeCachingReaderBuilder(TestingCommons.tracerMock()),
+                EthereumChainSpecific.INSTANCE.&localReaderBuilder,
+                EthereumChainSpecific.INSTANCE.subscriptionBuilder(Schedulers.boundedElastic()))
        when:
        ms.onUpstreamChange(
                new UpstreamChangeEvent(Chain.ETHEREUM__MAINNET, up1, UpstreamChangeEvent.ChangeType.ADDED)
@@ -278,9 +292,13 @@ class MultistreamSpec extends Specification {

    def "Filter older blocks on multistream head"() {
        setup:
-        def up1 = new EthereumPosRpcUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test1", "eth_test2", "eth_test3"]))
-        def up2 = new EthereumPosRpcUpstreamMock("test2", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test1", "eth_test2"]))
-        def ms = new EthereumPosMultiStream(Chain.ETHEREUM__MAINNET, new ArrayList<EthereumLikeRpcUpstream>(), Caches.default(), Schedulers.boundedElastic(), TestingCommons.tracerMock())
+        def up1 = new GenericUpstreamMock("test1", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test1", "eth_test2", "eth_test3"]))
+        def up2 = new GenericUpstreamMock("test2", Chain.ETHEREUM__MAINNET, TestingCommons.api(), new DirectCallMethods(["eth_test1", "eth_test2"]))
+        def ms = new GenericMultistream(Chain.ETHEREUM__MAINNET, new ArrayList<GenericMultistream>(), Caches.default(),
+                Schedulers.boundedElastic(),
+                EthereumChainSpecific.INSTANCE.makeCachingReaderBuilder(TestingCommons.tracerMock()),
+                EthereumChainSpecific.INSTANCE.&localReaderBuilder,
+                EthereumChainSpecific.INSTANCE.subscriptionBuilder(Schedulers.boundedElastic()))
        def head1 = createBlock(250, "0x0d050c785de17179f935b9b93aca09c442964cc59972c71ae68e74731448401b")
        def head2 = createBlock(270, "0x0d050c785de17179f935b9b93aca09c442964cc59972c71ae68e74731448402b")
        def head3 = createBlock(100, "0x0d050c785de17179f935b9b93aca09c442964cc59972c71ae68e74731448412b")
@@ -311,7 +329,11 @@ class MultistreamSpec extends Specification {
        def up1 = TestingCommons.upstream("test-1", "internal")
        def up2 = TestingCommons.upstream("test-2", "external")
        def up3 = TestingCommons.upstream("test-3", "external")
-        def multistream = new EthereumPosMultiStream(Chain.ETHEREUM__MAINNET, [up1, up2, up3], Caches.default(), Schedulers.boundedElastic(), TestingCommons.tracerMock())
+        def multistream = new GenericMultistream(Chain.ETHEREUM__MAINNET, [up1, up2, up3], Caches.default(),
+                Schedulers.boundedElastic(),
+                EthereumChainSpecific.INSTANCE.makeCachingReaderBuilder(TestingCommons.tracerMock()),
+                EthereumChainSpecific.INSTANCE.&localReaderBuilder,
+                EthereumChainSpecific.INSTANCE.subscriptionBuilder(Schedulers.boundedElastic()))
        def observer = multistream.lagObserver
        multistream.onUpstreamsUpdated()

@@ -335,15 +357,19 @@ class MultistreamSpec extends Specification {
                .build()
    }

-    class TestEthereumPosMultistream extends EthereumPosMultiStream {
+    class TestEthereumPosMultistream extends GenericMultistream {

-        TestEthereumPosMultistream(@NotNull Chain chain, @NotNull List<EthereumLikeRpcUpstream> upstreams, @NotNull Caches caches) {
-            super(chain, upstreams, caches, Schedulers.boundedElastic(), TestingCommons.tracerMock())
+        TestEthereumPosMultistream(@NotNull Chain chain, @NotNull List<GenericUpstream> upstreams, @NotNull Caches caches) {
+            super(chain, upstreams, caches,
+                    Schedulers.boundedElastic(),
+                    EthereumChainSpecific.INSTANCE.makeCachingReaderBuilder(TestingCommons.tracerMock()),
+                    EthereumChainSpecific.INSTANCE.&localReaderBuilder,
+                    StarknetChainSpecific.INSTANCE.subscriptionBuilder(Schedulers.boundedElastic()))
        }

        @NotNull
        @Override
-        Mono<Reader<JsonRpcRequest, JsonRpcResponse>> getLocalReader(boolean localEnabled) {
+        Mono<Reader<JsonRpcRequest, JsonRpcResponse>> getLocalReader() {
            return null
        }

--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/ERC20BalanceSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/ERC20BalanceSpec.groovy
@@ -1,91 +0,0 @@
-/**
- * Copyright (c) 2021 EmeraldPay, Inc
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import io.emeraldpay.dshackle.Chain
-import io.emeraldpay.dshackle.test.EthereumPosRpcUpstreamMock
-import io.emeraldpay.dshackle.test.ReaderMock
-import io.emeraldpay.dshackle.upstream.ApiSource
-import io.emeraldpay.dshackle.upstream.FilteredApis
-import io.emeraldpay.dshackle.upstream.Selector
-import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
-import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
-import io.emeraldpay.etherjar.domain.Address
-import io.emeraldpay.etherjar.erc20.ERC20Token
-import io.emeraldpay.etherjar.hex.HexData
-import io.emeraldpay.etherjar.rpc.json.TransactionCallJson
-import spock.lang.Specification
-
-import java.time.Duration
-
-class ERC20BalanceSpec extends Specification {
-
-    def "Gets balance from upstream"() {
-        setup:
-        ReaderMock api = new ReaderMock()
-                .with(
-                        new JsonRpcRequest("eth_call", [
-                                new TransactionCallJson().tap { json ->
-                                    json.setTo(Address.from("0x54EedeAC495271d0F6B175474E89094C44Da98b9"))
-                                    json.setData(HexData.from("0x70a0823100000000000000000000000016c15c65ad00b6dfbcc2cb8a7b6c2d0103a3883b"))
-                                },
-                                "latest"
-                        ]),
-                        JsonRpcResponse.ok('"0x0000000000000000000000000000000000000000000000000000001f28d72868"')
-                )
-
-        EthereumLikeRpcUpstream upstream = new EthereumPosRpcUpstreamMock(Chain.ETHEREUM__MAINNET, api)
-        ERC20Token token = new ERC20Token(Address.from("0x54EedeAC495271d0F6B175474E89094C44Da98b9"))
-        ERC20Balance query = new ERC20Balance()
-
-        when:
-        def act = query.getBalance(upstream, token, Address.from("0x16c15c65ad00b6dfbcc2cb8a7b6c2d0103a3883b"))
-                .block(Duration.ofSeconds(1))
-
-        then:
-        act.toLong() == 0x1f28d72868
-    }
-
-    def "Gets balance from api source"() {
-        setup:
-        ReaderMock api = new ReaderMock()
-                .with(
-                        new JsonRpcRequest("eth_call", [
-                                new TransactionCallJson().tap { json ->
-                                    json.setTo(Address.from("0x54EedeAC495271d0F6B175474E89094C44Da98b9"))
-                                    json.setData(HexData.from("0x70a0823100000000000000000000000016c15c65ad00b6dfbcc2cb8a7b6c2d0103a3883b"))
-                                },
-                                "latest"
-                        ]),
-                        JsonRpcResponse.ok('"0x0000000000000000000000000000000000000000000000000000001f28d72868"')
-                )
-
-        EthereumLikeRpcUpstream upstream = new EthereumPosRpcUpstreamMock(Chain.ETHEREUM__MAINNET, api)
-        ERC20Token token = new ERC20Token(Address.from("0x54EedeAC495271d0F6B175474E89094C44Da98b9"))
-        ERC20Balance query = new ERC20Balance()
-
-        ApiSource apiSource = new FilteredApis(
-                Chain.ETHEREUM__MAINNET, [upstream], Selector.empty
-        )
-
-        when:
-        def act = query.getBalance(apiSource, token, Address.from("0x16c15c65ad00b6dfbcc2cb8a7b6c2d0103a3883b"))
-                .block(Duration.ofSeconds(1))
-
-        then:
-        act.toLong() == 0x1f28d72868
-    }
-}
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumEgressSubscriptionSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumEgressSubscriptionSpec.groovy
@@ -17,6 +17,7 @@ package io.emeraldpay.dshackle.upstream.ethereum


 import io.emeraldpay.dshackle.test.TestingCommons
+import io.emeraldpay.dshackle.upstream.generic.GenericMultistream
 import io.emeraldpay.dshackle.upstream.ethereum.subscribe.PendingTxesSource
 import io.emeraldpay.etherjar.domain.Address
 import io.emeraldpay.etherjar.hex.Hex32
@@ -28,7 +29,7 @@ class EthereumEgressSubscriptionSpec extends Specification {

    def "read empty logs request"() {
        setup:
-        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
+        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as GenericMultistream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
        when:
        def act = ethereumSubscribe.readLogsRequest([:])

@@ -39,7 +40,7 @@ class EthereumEgressSubscriptionSpec extends Specification {

    def "read single address logs request"() {
        setup:
-        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
+        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as GenericMultistream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
        when:
        def act = ethereumSubscribe.readLogsRequest([
                address: "0x829bd824b016326a401d083b33d092293333a830"
@@ -64,7 +65,7 @@ class EthereumEgressSubscriptionSpec extends Specification {

    def "ignores invalid address for logs request"() {
        setup:
-        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
+        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as GenericMultistream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
        when:
        def act = ethereumSubscribe.readLogsRequest([
                address: "829bd824b016326a401d083b33d092293333a830"
@@ -77,7 +78,7 @@ class EthereumEgressSubscriptionSpec extends Specification {

    def "read multi address logs request"() {
        setup:
-        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
+        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as GenericMultistream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
        when:
        def act = ethereumSubscribe.readLogsRequest([
                address: ["0x829bd824b016326a401d083b33d092293333a830", "0x401d083b33d092293333a83829bd824b016326a0"]
@@ -93,7 +94,7 @@ class EthereumEgressSubscriptionSpec extends Specification {

    def "read single topic logs request"() {
        setup:
-        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
+        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as GenericMultistream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
        when:
        def act = ethereumSubscribe.readLogsRequest([
                topics: "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"
@@ -118,7 +119,7 @@ class EthereumEgressSubscriptionSpec extends Specification {

    def "read invalid topic for request"() {
        setup:
-        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
+        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as GenericMultistream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
        when:
        def act = ethereumSubscribe.readLogsRequest([
                topics: [
@@ -136,7 +137,7 @@ class EthereumEgressSubscriptionSpec extends Specification {

    def "read multi topic logs request"() {
        setup:
-        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
+        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as GenericMultistream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
        when:
        def act = ethereumSubscribe.readLogsRequest([
                topics: [
@@ -155,7 +156,7 @@ class EthereumEgressSubscriptionSpec extends Specification {

    def "read full logs request"() {
        setup:
-        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
+        def ethereumSubscribe = new EthereumEgressSubscription(TestingCommons.emptyMultistream() as GenericMultistream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
        when:
        def act = ethereumSubscribe.readLogsRequest([
                address: "0x298d492e8c1d909d3f63bc4a36c66c64acb3d695",
@@ -180,7 +181,7 @@ class EthereumEgressSubscriptionSpec extends Specification {
        def up1 = TestingCommons.upstream("test")
        up1.getConnectorMock().setLiveness(Flux.just(false))

-        def ethereumSubscribe1 = new EthereumEgressSubscription(TestingCommons.multistream(up1) as EthereumPosMultiStream, Schedulers.boundedElastic(), null)
+        def ethereumSubscribe1 = new EthereumEgressSubscription(TestingCommons.multistream(up1) as GenericMultistream, Schedulers.boundedElastic(), null)
        then:
        ethereumSubscribe1.getAvailableTopics() == []
        when:
@@ -188,7 +189,7 @@ class EthereumEgressSubscriptionSpec extends Specification {
        up2.getConnectorMock().setLiveness(Flux.just(true))
        up2.stop()
        up2.start()
-        def ethereumSubscribe2 = new EthereumEgressSubscription(TestingCommons.multistream(up2) as EthereumPosMultiStream, Schedulers.boundedElastic(), null)
+        def ethereumSubscribe2 = new EthereumEgressSubscription(TestingCommons.multistream(up2) as GenericMultistream, Schedulers.boundedElastic(), null)
        then:
        ethereumSubscribe2.getAvailableTopics().toSet() == [EthereumEgressSubscription.METHOD_LOGS, EthereumEgressSubscription.METHOD_NEW_HEADS].toSet()
        when:
@@ -196,7 +197,7 @@ class EthereumEgressSubscriptionSpec extends Specification {
        up3.getConnectorMock().setLiveness(Flux.just(true))
        up3.stop()
        up3.start()
-        def ethereumSubscribe3 = new EthereumEgressSubscription(TestingCommons.multistream(up3) as EthereumPosMultiStream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
+        def ethereumSubscribe3 = new EthereumEgressSubscription(TestingCommons.multistream(up3) as GenericMultistream, Schedulers.boundedElastic(), Stub(PendingTxesSource))
        then:
        ethereumSubscribe3.getAvailableTopics().toSet() == [EthereumEgressSubscription.METHOD_LOGS, EthereumEgressSubscription.METHOD_NEW_HEADS, EthereumEgressSubscription.METHOD_PENDING_TXES].toSet()

--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumLegacyFeesSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumLegacyFeesSpec.groovy
@@ -1,41 +0,0 @@
-/**
- * Copyright (c) 2021 EmeraldPay, Inc
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import io.emeraldpay.dshackle.upstream.ethereum.json.BlockJson
-import io.emeraldpay.dshackle.upstream.ethereum.json.TransactionJsonSnapshot
-import io.emeraldpay.etherjar.domain.Wei
-import spock.lang.Specification
-
-class EthereumLegacyFeesSpec extends Specification {
-
-    def "Extract fee from"() {
-        setup:
-        def block = new BlockJson()
-        // 0x75cc01873a9818bf426a8b23d83450bf18530a822fd4fe9e86a416a5554176a6
-        def tx = new TransactionJsonSnapshot().tap {
-            it.gasPrice = Wei.ofUnits(8, Wei.Unit.GWEI)
-        }
-
-        def fees = new EthereumLegacyFees(Stub(EthereumMultistream), Stub(EthereumCachingReader), 10)
-        when:
-        def act = fees.extractFee(block, tx)
-        then:
-        act.priority == Wei.ofUnits(8, Wei.Unit.GWEI)
-        act.max == Wei.ofUnits(8, Wei.Unit.GWEI)
-        act.base == Wei.ZERO
-    }
-}
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumLocalReaderSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumLocalReaderSpec.groovy
@@ -30,8 +30,7 @@ class EthereumLocalReaderSpec extends Specification {
                        TestingCommons.tracerMock()
                ),
                methods,
-                new EmptyHead(),
-                true
+                new EmptyHead()
        )
        when:
        def act = router.read(new JsonRpcRequest("eth_coinbase", [])).block(Duration.ofSeconds(1))
@@ -50,8 +49,7 @@ class EthereumLocalReaderSpec extends Specification {
                        TestingCommons.tracerMock()
                ),
                methods,
-                new EmptyHead(),
-                true
+                new EmptyHead()
        )
        when:
        def act = router.read(new JsonRpcRequest("eth_getTransactionByHash", ["test"], 10))
@@ -75,7 +73,7 @@ class EthereumLocalReaderSpec extends Specification {
            }
        }
        def methods = new DefaultEthereumMethods(Chain.ETHEREUM__MAINNET)
-        def router = new EthereumLocalReader(reader, methods, head, true)
+        def router = new EthereumLocalReader(reader, methods, head)

        when:
        def act = router.getBlockByNumber(["latest", false])
@@ -103,7 +101,7 @@ class EthereumLocalReaderSpec extends Specification {
            }
        }
        def methods = new DefaultEthereumMethods(Chain.ETHEREUM__MAINNET)
-        def router = new EthereumLocalReader(reader, methods, head, true)
+        def router = new EthereumLocalReader(reader, methods, head)

        when:
        def act = router.getBlockByNumber(["earliest", false])
@@ -131,7 +129,7 @@ class EthereumLocalReaderSpec extends Specification {
            }
        }
        def methods = new DefaultEthereumMethods(Chain.ETHEREUM__MAINNET)
-        def router = new EthereumLocalReader(reader, methods, head, true)
+        def router = new EthereumLocalReader(reader, methods, head)

        when:
        def act = router.getBlockByNumber(["0x123ef", false])
@@ -155,7 +153,7 @@ class EthereumLocalReaderSpec extends Specification {
            _ * blocksByHeightAsCont() >> new EmptyReader<>()
        }
        def methods = new DefaultEthereumMethods(Chain.ETHEREUM__MAINNET)
-        def router = new EthereumLocalReader(reader, methods, head, true)
+        def router = new EthereumLocalReader(reader, methods, head)

        when:
        def act = router.getBlockByNumber(["0x0", true])
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumPriorityFeesSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumPriorityFeesSpec.groovy
@@ -1,150 +0,0 @@
-/**
- * Copyright (c) 2021 EmeraldPay, Inc
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.ethereum
-
-import io.emeraldpay.dshackle.reader.Reader
-import io.emeraldpay.dshackle.upstream.ChainFees
-import io.emeraldpay.dshackle.upstream.Head
-import io.emeraldpay.dshackle.upstream.ethereum.json.BlockJson
-import io.emeraldpay.dshackle.upstream.ethereum.json.TransactionJsonSnapshot
-import io.emeraldpay.etherjar.domain.TransactionId
-import io.emeraldpay.etherjar.domain.Wei
-import io.emeraldpay.etherjar.rpc.json.TransactionRefJson
-import reactor.core.publisher.Flux
-import reactor.core.publisher.Mono
-import spock.lang.Specification
-
-import java.time.Duration
-
-class EthereumPriorityFeesSpec extends Specification {
-
-    def "Extract fee from EIP1559 tx"() {
-        setup:
-        // 13756007
-        def block = new BlockJson().tap {
-            it.baseFeePerGas = new Wei(104197355513)
-        }
-        // 0x5da50f35a51e56ecd4313417b1c30f9c088222f3f8763701effe14f3dd18b6cc
-        def tx = new TransactionJsonSnapshot().tap {
-            it.type = 2
-            it.maxFeePerGas = Wei.ofUnits(999, Wei.Unit.GWEI)
-            it.maxPriorityFeePerGas = Wei.ofUnits(5.0001, Wei.Unit.GWEI)
-        }
-
-        def fees = new EthereumPriorityFees(Stub(EthereumMultistream), Stub(EthereumCachingReader), 10)
-        when:
-        def act = fees.extractFee(block, tx)
-        then:
-        act.priority == Wei.ofUnits(5.0001, Wei.Unit.GWEI)
-        act.max == Wei.ofUnits(999, Wei.Unit.GWEI)
-        act.base == new Wei(104197355513)
-    }
-
-    def "Extract fee from legacy tx"() {
-        setup:
-        // 13756007
-        def block = new BlockJson().tap {
-            it.baseFeePerGas = new Wei(104197355513)
-        }
-        // 0x1f507982bef0f11a8304287d41f228b5f1dda1114a446ee781c3d95ef4a7b891
-        def tx = new TransactionJsonSnapshot().tap {
-            it.type = 0
-            // 109.564020111 Gwei
-            it.gasPrice = Wei.from("0x198286458f")
-        }
-
-        def fees = new EthereumPriorityFees(Stub(EthereumMultistream), Stub(EthereumCachingReader), 10)
-        when:
-        def act = fees.extractFee(block, tx)
-        then:
-        // as difference between base minimum and actually paid
-        act.priority == Wei.ofUnits(5.366664598, Wei.Unit.GWEI)
-        act.max == Wei.from("0x198286458f")
-        act.base == new Wei(104197355513)
-    }
-
-    def "Calculates average fee"() {
-        setup:
-        def inputs = [
-                new EthereumFees.EthereumFee(Wei.ofEthers(1), Wei.ofEthers(0.5), Wei.ofEthers(0.75), Wei.ofEthers(0.5)),
-                new EthereumFees.EthereumFee(Wei.ofEthers(0.75), Wei.ofEthers(0.5), Wei.ofEthers(0.75), Wei.ofEthers(0.5)),
-                new EthereumFees.EthereumFee(Wei.ofEthers(0.6), Wei.ofEthers(0.2), Wei.ofEthers(0.6), Wei.ofEthers(0.5)),
-        ]
-        def fees = new EthereumPriorityFees(Stub(EthereumMultistream), Stub(EthereumCachingReader), 10)
-        when:
-        def act = Flux.fromIterable(inputs)
-                .transform(fees.feeAggregation(ChainFees.Mode.AVG_LAST))
-                .next().block(Duration.ofSeconds(1))
-        then:
-        act.priority == Wei.ofEthers(0.4) // 0.5 + 0.5 + 0.2
-        act.paid == Wei.ofEthers(0.7) // 0.75 + 0.75 + 0.6
-    }
-
-    def "Estimate"() {
-        setup:
-        def block1 = new BlockJson().tap {
-            it.baseFeePerGas = new Wei(92633661632)
-            it.transactions = [
-                    new TransactionRefJson(TransactionId.from("0x00000000fad596cad644b785a8a74f6580ceec9ae13c8aa174f819c0223b8c77")),
-                    new TransactionRefJson(TransactionId.from("0x11111111fad596cad644b785a8a74f6580ceec9ae13c8aa174f819c0223b8c77")),
-                    new TransactionRefJson(TransactionId.from("0x22222222fad596cad644b785a8a74f6580ceec9ae13c8aa174f819c0223b8c77")),
-            ]
-        }
-        def block2 = new BlockJson().tap {
-            it.baseFeePerGas = new Wei(104197355513)
-            it.transactions = [
-                    new TransactionRefJson(TransactionId.from("0x33333333fad596cad644b785a8a74f6580ceec9ae13c8aa174f819c0223b8c77")),
-                    new TransactionRefJson(TransactionId.from("0x44444444fad596cad644b785a8a74f6580ceec9ae13c8aa174f819c0223b8c77")),
-                    new TransactionRefJson(TransactionId.from("0x55555555fad596cad644b785a8a74f6580ceec9ae13c8aa174f819c0223b8c77")),
-            ]
-        }
-        def tx1 = new TransactionJsonSnapshot().tap {
-            it.type = 2
-            it.maxFeePerGas = Wei.ofUnits(150, Wei.Unit.GWEI)
-            it.maxPriorityFeePerGas = Wei.ofUnits(3, Wei.Unit.GWEI)
-        }
-        def tx2 = new TransactionJsonSnapshot().tap {
-            it.type = 2
-            it.maxFeePerGas = Wei.ofUnits(200, Wei.Unit.GWEI)
-            it.maxPriorityFeePerGas = Wei.ofUnits(6, Wei.Unit.GWEI)
-        }
-
-        def ups = Mock(EthereumMultistream) {
-            1 * getHead() >> Mock(Head) {
-                1 * getCurrentHeight() >> 13756007
-            }
-        }
-        def reader = Mock(EthereumCachingReader) {
-            _ * it.blocksByHeightParsed() >> Mock(Reader) {
-                1 * it.read(13756006) >> Mono.just(block1)
-                1 * it.read(13756007) >> Mono.just(block2)
-            }
-            _ * it.txByHash() >> Mock(Reader) {
-                1 * it.read(TransactionId.from("0x22222222fad596cad644b785a8a74f6580ceec9ae13c8aa174f819c0223b8c77")) >> Mono.just(tx1)
-                1 * it.read(TransactionId.from("0x55555555fad596cad644b785a8a74f6580ceec9ae13c8aa174f819c0223b8c77")) >> Mono.just(tx2)
-            }
-        }
-        def fees = new EthereumPriorityFees(ups, reader, 10)
-        when:
-        def act = fees.estimate(ChainFees.Mode.AVG_LAST, 2).block(Duration.ofSeconds(1))
-
-        then:
-        act.hasEthereumExtended()
-        act.ethereumExtended.priority == "4500000000"
-        act.ethereumExtended.max == "175000000000"
-        act.ethereumExtended.expect == "102915508572"
-    }
-}
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumUpstreamValidatorSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumUpstreamValidatorSpec.groovy
@@ -24,6 +24,7 @@ import io.emeraldpay.dshackle.upstream.Head
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcError
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcResponse
+import io.emeraldpay.dshackle.upstream.Upstream
 import io.emeraldpay.etherjar.domain.Address
 import io.emeraldpay.etherjar.hex.HexData
 import io.emeraldpay.etherjar.rpc.RpcResponseError
@@ -37,16 +38,20 @@ import java.time.Duration
 import static io.emeraldpay.dshackle.Chain.ETHEREUM__MAINNET
 import static io.emeraldpay.dshackle.Chain.OPTIMISM__MAINNET
 import static io.emeraldpay.dshackle.upstream.UpstreamAvailability.*
-import static io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstreamValidator.ValidateUpstreamSettingsResult.UPSTREAM_FATAL_SETTINGS_ERROR
-import static io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstreamValidator.ValidateUpstreamSettingsResult.UPSTREAM_SETTINGS_ERROR
-import static io.emeraldpay.dshackle.upstream.ethereum.EthereumUpstreamValidator.ValidateUpstreamSettingsResult.UPSTREAM_VALID
+import static io.emeraldpay.dshackle.upstream.ValidateUpstreamSettingsResult.UPSTREAM_FATAL_SETTINGS_ERROR
+import static io.emeraldpay.dshackle.upstream.ValidateUpstreamSettingsResult.UPSTREAM_SETTINGS_ERROR
+import static io.emeraldpay.dshackle.upstream.ValidateUpstreamSettingsResult.UPSTREAM_VALID
 import static java.util.Collections.emptyList
+import io.emeraldpay.dshackle.config.ChainsConfig.ChainConfig

 class EthereumUpstreamValidatorSpec extends Specification {

+    def conf = ChainConfig.defaultWithContract("0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96")
+
    def "Resolve to final availability"() {
        setup:
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, Stub(EthereumLikeUpstream), ChainOptions.PartialOptions.getDefaults().buildOptions())
+
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, Stub(Upstream), ChainOptions.PartialOptions.getDefaults().buildOptions(), conf)
        expect:
        validator.resolve(Tuples.of(sync, peers)) == exp
        where:
@@ -67,8 +72,8 @@ class EthereumUpstreamValidatorSpec extends Specification {
        def options = ChainOptions.PartialOptions.getDefaults().tap {
            it.validateSyncing = false
        }.buildOptions()
-        def up = Mock(EthereumLikeUpstream)
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def up = Mock(Upstream)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validateSyncing().block(Duration.ofSeconds(1))
@@ -87,7 +92,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
                    answer("eth_syncing", [], false)
                }
        )
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validateSyncing().block(Duration.ofSeconds(1))
@@ -100,7 +105,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
        def options = ChainOptions.PartialOptions.getDefaults().tap {
            it.validateSyncing = true
        }.buildOptions()
-        def up = Mock(EthereumLikeUpstream) {
+        def up = Mock(Upstream) {
            2 * getIngressReader() >> Mock(Reader) { reader ->
                2 * reader.read(_) >>> [
                        Mono.just(new JsonRpcResponse('true'.getBytes(), null)),
@@ -112,7 +117,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
                1 * head.onSyncingNode(false)
            }
        }
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validateSyncing().block(Duration.ofSeconds(1))
@@ -132,7 +137,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
                    answer("eth_syncing", [], [startingBlock: 100, currentBlock: 50])
                }
        )
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validateSyncing().block(Duration.ofSeconds(1))
@@ -150,7 +155,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
                    answer("eth_syncing", [], new RpcResponseError(RpcResponseError.CODE_METHOD_NOT_EXIST, "Unavailable"))
                }
        )
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validateSyncing().block(Duration.ofSeconds(1))
@@ -164,8 +169,8 @@ class EthereumUpstreamValidatorSpec extends Specification {
            it.validatePeers = false
            it.minPeers = 10
        }.buildOptions()
-        def up = Mock(EthereumLikeUpstream)
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def up = Mock(Upstream)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validatePeers().block(Duration.ofSeconds(1))
@@ -180,8 +185,8 @@ class EthereumUpstreamValidatorSpec extends Specification {
            it.validatePeers = true
            it.minPeers = 0
        }.buildOptions()
-        def up = Mock(EthereumLikeUpstream)
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def up = Mock(Upstream)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validatePeers().block(Duration.ofSeconds(1))
@@ -201,7 +206,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
                    answer("net_peerCount", [], "0x5")
                }
        )
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validatePeers().block(Duration.ofSeconds(1))
@@ -220,7 +225,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
                    answer("net_peerCount", [], "0xa")
                }
        )
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validatePeers().block(Duration.ofSeconds(1))
@@ -239,7 +244,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
                    answer("net_peerCount", [], "0xff")
                }
        )
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validatePeers().block(Duration.ofSeconds(1))
@@ -258,7 +263,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
                    answer("net_peerCount", [], new RpcResponseError(RpcResponseError.CODE_METHOD_NOT_EXIST, "Unavailable"))
                }
        )
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validatePeers().block(Duration.ofSeconds(1))
@@ -272,7 +277,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
            it.validateCalllimit = false
            it.validateChain = false
        }.buildOptions()
-        def up = Mock(EthereumLikeUpstream) {
+        def up = Mock(Upstream) {
            2 * getIngressReader() >>
                    Mock(Reader) {
                        1 * read(new JsonRpcRequest("eth_blockNumber", [])) >> Mono.just(new JsonRpcResponse('"0x10ff9be"'.getBytes(), null))
@@ -280,7 +285,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
                                Mono.just(new JsonRpcResponse('"result"'.getBytes(), null))
                    }
        }
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options)
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)

        when:
        def act = validator.validateUpstreamSettingsOnStartup()
@@ -293,7 +298,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
        def options = ChainOptions.PartialOptions.getDefaults().tap {
            it.validateChain = false
        }.buildOptions()
-        def up = Mock(EthereumLikeRpcUpstream) {
+        def up = Mock(Upstream) {
            3 * getIngressReader() >> Mock(Reader) {
                1 * read(new JsonRpcRequest("eth_call", [new TransactionCallJson(
                        Address.from("0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96"),
@@ -304,8 +309,8 @@ class EthereumUpstreamValidatorSpec extends Specification {
                        Mono.just(new JsonRpcResponse('"result"'.getBytes(), null))
            }
        }
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, "0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96")
-
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)
+//"0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96
        when:
        def act = validator.validateUpstreamSettingsOnStartup()
        then:
@@ -317,7 +322,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
        def options = ChainOptions.PartialOptions.getDefaults().tap {
            it.validateChain = false
        }.buildOptions()
-        def up = Mock(EthereumLikeRpcUpstream) {
+        def up = Mock(Upstream) {
            3 * getIngressReader() >> Mock(Reader) {
                1 * read(new JsonRpcRequest("eth_call", [new TransactionCallJson(
                        Address.from("0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96"),
@@ -328,8 +333,8 @@ class EthereumUpstreamValidatorSpec extends Specification {
                        Mono.just(new JsonRpcResponse('"result"'.getBytes(), null))
            }
        }
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, "0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96")
-
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)
+// "0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96"
        when:
        def act = validator.validateUpstreamSettingsOnStartup()
        then:
@@ -341,7 +346,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
        def options = ChainOptions.PartialOptions.getDefaults().tap {
            it.validateCalllimit = false
        }.buildOptions()
-        def up = Mock(EthereumLikeRpcUpstream) {
+        def up = Mock(Upstream) {
            4 * getIngressReader() >> Mock(Reader) {
                1 * read(new JsonRpcRequest("eth_chainId", emptyList())) >> Mono.just(new JsonRpcResponse('"0x1"'.getBytes(), null))
                1 * read(new JsonRpcRequest("net_version", emptyList())) >> Mono.just(new JsonRpcResponse('"1"'.getBytes(), null))
@@ -350,8 +355,8 @@ class EthereumUpstreamValidatorSpec extends Specification {
                        Mono.just(new JsonRpcResponse('"result"'.getBytes(), null))
            }
        }
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, "0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96")
-
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)
+// "0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96"
        when:
        def act = validator.validateUpstreamSettingsOnStartup()
        then:
@@ -363,7 +368,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
        def options = ChainOptions.PartialOptions.getDefaults().tap {
            it.validateCalllimit = false
        }.buildOptions()
-        def up = Mock(EthereumLikeRpcUpstream) {
+        def up = Mock(Upstream) {
            4 * getIngressReader() >> Mock(Reader) {
                1 * read(new JsonRpcRequest("eth_chainId", emptyList())) >> Mono.just(new JsonRpcResponse('"0x1"'.getBytes(), null))
                1 * read(new JsonRpcRequest("net_version", emptyList())) >> Mono.just(new JsonRpcResponse('"1"'.getBytes(), null))
@@ -372,8 +377,8 @@ class EthereumUpstreamValidatorSpec extends Specification {
                        Mono.just(new JsonRpcResponse('"result"'.getBytes(), null))
            }
        }
-        def validator = new EthereumUpstreamValidator(OPTIMISM__MAINNET, up, options, "0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96")
-
+        def validator = new EthereumUpstreamValidator(OPTIMISM__MAINNET, up, options, conf)
+// "0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96"
        when:
        def act = validator.validateUpstreamSettingsOnStartup()
        then:
@@ -383,7 +388,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
    def "Upstream is valid if all setting are valid"() {
        setup:
        def options = ChainOptions.PartialOptions.getDefaults().buildOptions()
-        def up = Mock(EthereumLikeRpcUpstream) {
+        def up = Mock(Upstream) {
            5 * getIngressReader() >> Mock(Reader) {
                1 * read(new JsonRpcRequest("eth_chainId", emptyList())) >> Mono.just(new JsonRpcResponse('"0x1"'.getBytes(), null))
                1 * read(new JsonRpcRequest("net_version", emptyList())) >> Mono.just(new JsonRpcResponse('"1"'.getBytes(), null))
@@ -396,8 +401,8 @@ class EthereumUpstreamValidatorSpec extends Specification {
                        Mono.just(new JsonRpcResponse('"result"'.getBytes(), null))
            }
        }
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, "0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96")
-
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)
+// "0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96"
        when:
        def act = validator.validateUpstreamSettingsOnStartup()
        then:
@@ -407,7 +412,7 @@ class EthereumUpstreamValidatorSpec extends Specification {
    def "Upstream is not valid if there are errors"() {
        setup:
        def options = ChainOptions.PartialOptions.getDefaults().buildOptions()
-        def up = Mock(EthereumLikeRpcUpstream) {
+        def up = Mock(Upstream) {
            5 * getIngressReader() >> Mock(Reader) {
                1 * read(new JsonRpcRequest("eth_chainId", emptyList())) >> Mono.just(new JsonRpcResponse(null, new JsonRpcError(1, "Too long")))
                1 * read(new JsonRpcRequest("net_version", emptyList())) >> Mono.just(new JsonRpcResponse(null, new JsonRpcError(1, "Too long")))
@@ -420,8 +425,8 @@ class EthereumUpstreamValidatorSpec extends Specification {
                        Mono.just(new JsonRpcResponse('"result"'.getBytes(), null))
            }
        }
-        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, "0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96")
-
+        def validator = new EthereumUpstreamValidator(ETHEREUM__MAINNET, up, options, conf)
+// "0x32268860cAAc2948Ab5DdC7b20db5a420467Cf96"
        when:
        def act = validator.validateUpstreamSettingsOnStartup()
        then:
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumWsHeadSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/EthereumWsHeadSpec.groovy
@@ -18,7 +18,7 @@ package io.emeraldpay.dshackle.upstream.ethereum
 import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.Global
 import io.emeraldpay.dshackle.data.BlockContainer
-import io.emeraldpay.dshackle.test.EthereumPosRpcUpstreamMock
+import io.emeraldpay.dshackle.test.GenericUpstreamMock
 import io.emeraldpay.dshackle.test.TestingCommons
 import io.emeraldpay.dshackle.upstream.BlockValidator
 import io.emeraldpay.dshackle.upstream.DefaultUpstream
@@ -41,7 +41,7 @@ import java.time.temporal.ChronoUnit
 class EthereumWsHeadSpec extends Specification {

    BlockHash parent = BlockHash.from("0x3ec2ebf5d0ec474d0ac6bc50d2770d8409ad76e119968e7919f85d5ec8915200")
-    DefaultUpstream upstream = new EthereumPosRpcUpstreamMock(Chain.ETHEREUM__MAINNET, TestingCommons.api())
+    DefaultUpstream upstream = new GenericUpstreamMock(Chain.ETHEREUM__MAINNET, TestingCommons.api())

    def "Fetch block"() {
        setup:
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/WsConnectionImplRealSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/WsConnectionImplRealSpec.groovy
@@ -1,7 +1,7 @@
 package io.emeraldpay.dshackle.upstream.ethereum

 import io.emeraldpay.dshackle.Chain
-import io.emeraldpay.dshackle.test.EthereumPosRpcUpstreamMock
+import io.emeraldpay.dshackle.test.GenericUpstreamMock
 import io.emeraldpay.dshackle.test.MockWSServer
 import io.emeraldpay.dshackle.test.TestingCommons
 import io.emeraldpay.dshackle.upstream.DefaultUpstream
@@ -15,7 +15,7 @@ import spock.lang.Specification
 import java.time.Duration

 class WsConnectionImplRealSpec extends Specification {
-    DefaultUpstream upstream = new EthereumPosRpcUpstreamMock(Chain.ETHEREUM__MAINNET, TestingCommons.api())
+    DefaultUpstream upstream = new GenericUpstreamMock(Chain.ETHEREUM__MAINNET, TestingCommons.api())

    static SLEEP = 500

--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/WsConnectionImplSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/WsConnectionImplSpec.groovy
@@ -17,7 +17,7 @@ package io.emeraldpay.dshackle.upstream.ethereum

 import io.emeraldpay.dshackle.Chain
 import io.emeraldpay.dshackle.Global
-import io.emeraldpay.dshackle.test.EthereumPosRpcUpstreamMock
+import io.emeraldpay.dshackle.test.GenericUpstreamMock
 import io.emeraldpay.dshackle.test.TestingCommons
 import io.emeraldpay.dshackle.upstream.DefaultUpstream
 import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcRequest
@@ -32,7 +32,7 @@ import spock.lang.Specification
 import java.time.Duration

 class WsConnectionImplSpec extends Specification {
-    DefaultUpstream upstream = new EthereumPosRpcUpstreamMock(Chain.ETHEREUM__MAINNET, TestingCommons.api())
+    DefaultUpstream upstream = new GenericUpstreamMock(Chain.ETHEREUM__MAINNET, TestingCommons.api())

    def "Makes a RPC call"() {
        setup:
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/subscribe/ConnectBlockUpdatesSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/subscribe/ConnectBlockUpdatesSpec.groovy
@@ -20,7 +20,7 @@ import io.emeraldpay.dshackle.data.BlockId
 import io.emeraldpay.dshackle.data.TxId
 import io.emeraldpay.dshackle.upstream.Head
 import io.emeraldpay.dshackle.upstream.Selector
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
+import io.emeraldpay.dshackle.upstream.generic.GenericMultistream
 import io.emeraldpay.etherjar.domain.BlockHash
 import io.emeraldpay.etherjar.domain.TransactionId
 import io.emeraldpay.dshackle.upstream.ethereum.json.BlockJson
@@ -38,7 +38,7 @@ class ConnectBlockUpdatesSpec extends Specification {

    def "Extracts updates"() {
        setup:
-        def connectBlockUpdates = new ConnectBlockUpdates(Stub(EthereumMultistream), Schedulers.boundedElastic())
+        def connectBlockUpdates = new ConnectBlockUpdates(Stub(GenericMultistream), Schedulers.boundedElastic())
        def block = BlockContainer.from(new BlockJson<TransactionRefJson>().tap {
            hash = BlockHash.from("0xe5be2159b2b7daf6b126babdcbaa349da668b92d6b8c7db1350fd527fec4885c")
            number = 13412871
@@ -72,7 +72,7 @@ class ConnectBlockUpdatesSpec extends Specification {

    def "Produce DROP updates for replaced block"() {
        setup:
-        def connectBlockUpdates = new ConnectBlockUpdates(Stub(EthereumMultistream), Schedulers.boundedElastic())
+        def connectBlockUpdates = new ConnectBlockUpdates(Stub(GenericMultistream), Schedulers.boundedElastic())
        def block = BlockContainer.from(new BlockJson<TransactionRefJson>().tap {
            hash = BlockHash.from("0xe5be2159b2b7daf6b126babdcbaa349da668b92d6b8c7db1350fd527fec4885c")
            number = 13412871
@@ -106,7 +106,7 @@ class ConnectBlockUpdatesSpec extends Specification {

    def "Gets prev version if available"() {
        setup:
-        def connectBlockUpdates = new ConnectBlockUpdates(Stub(EthereumMultistream), Schedulers.boundedElastic())
+        def connectBlockUpdates = new ConnectBlockUpdates(Stub(GenericMultistream), Schedulers.boundedElastic())
        def block1 = BlockContainer.from(new BlockJson<TransactionRefJson>().tap {
            hash = BlockHash.from("0xe5be2159b2b7daf6b126babdcbaa349da668b92d6b8c7db1350fd527fec4885c")
            number = 13412871
@@ -170,7 +170,7 @@ class ConnectBlockUpdatesSpec extends Specification {

    def "Marks old txes as dropped before producing a new version of same block"() {
        setup:
-        def connectBlockUpdates = new ConnectBlockUpdates(Stub(EthereumMultistream), Schedulers.boundedElastic())
+        def connectBlockUpdates = new ConnectBlockUpdates(Stub(GenericMultistream), Schedulers.boundedElastic())
        def block1 = BlockContainer.from(new BlockJson<TransactionRefJson>().tap {
            hash = BlockHash.from("0xe5be2159b2b7daf6b126babdcbaa349da668b92d6b8c7db1350fd527fec4885c")
            number = 13412871
@@ -232,7 +232,7 @@ class ConnectBlockUpdatesSpec extends Specification {
        def head = Mock(Head) {
            1 * getFlux() >> Flux.never()
        }
-        def up = Mock(EthereumMultistream) {
+        def up = Mock(GenericMultistream) {
            1 * getEnrichedHead(Selector.empty) >> head
        }
        def connectBlockUpdates = new ConnectBlockUpdates(up, Schedulers.boundedElastic())
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/subscribe/ConnectLogsSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/subscribe/ConnectLogsSpec.groovy
@@ -16,7 +16,6 @@
 package io.emeraldpay.dshackle.upstream.ethereum.subscribe

 import io.emeraldpay.dshackle.test.TestingCommons
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumPosMultiStream
 import io.emeraldpay.dshackle.upstream.ethereum.subscribe.json.LogMessage
 import io.emeraldpay.etherjar.domain.Address
 import io.emeraldpay.etherjar.domain.BlockHash
@@ -91,7 +90,7 @@ class ConnectLogsSpec extends Specification {

    def "Filter is empty"() {
        setup:
-        def connectLogs = new ConnectLogs(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic())
+        def connectLogs = new ConnectLogs(TestingCommons.emptyMultistream(), Schedulers.boundedElastic())
        when:
        def input = Flux.fromIterable([
                log1, log2, log3, log4
@@ -109,7 +108,7 @@ class ConnectLogsSpec extends Specification {

    def "Filter by address"() {
        setup:
-        def connectLogs = new ConnectLogs(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic())
+        def connectLogs = new ConnectLogs(TestingCommons.emptyMultistream(), Schedulers.boundedElastic())
        when:
        def input = Flux.fromIterable([
                log1, log2
@@ -124,7 +123,7 @@ class ConnectLogsSpec extends Specification {

    def "Filter by topic"() {
        setup:
-        def connectLogs = new ConnectLogs(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic())
+        def connectLogs = new ConnectLogs(TestingCommons.emptyMultistream(), Schedulers.boundedElastic())
        when:
        def input = Flux.fromIterable([
                log1, log2, log3, log4
@@ -141,7 +140,7 @@ class ConnectLogsSpec extends Specification {

    def "Filter by address and topic"() {
        setup:
-        def connectLogs = new ConnectLogs(TestingCommons.emptyMultistream() as EthereumPosMultiStream, Schedulers.boundedElastic())
+        def connectLogs = new ConnectLogs(TestingCommons.emptyMultistream(), Schedulers.boundedElastic())
        when:
        def input = Flux.fromIterable([
                log1, log2, log3, log4
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/subscribe/ConnectNewHeadsSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/subscribe/ConnectNewHeadsSpec.groovy
@@ -3,7 +3,7 @@ package io.emeraldpay.dshackle.upstream.ethereum.subscribe
 import io.emeraldpay.dshackle.test.TestingCommons
 import io.emeraldpay.dshackle.upstream.Head
 import io.emeraldpay.dshackle.upstream.Selector
-import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
+import io.emeraldpay.dshackle.upstream.generic.GenericMultistream
 import reactor.core.publisher.Flux
 import reactor.core.scheduler.Schedulers
 import reactor.test.StepVerifier
@@ -18,7 +18,7 @@ class ConnectNewHeadsSpec extends Specification {
                    TestingCommons.blockForEthereum(100)
            ])
        }
-        def up = Mock(EthereumMultistream) {
+        def up = Mock(GenericMultistream) {
            1 * getHead(Selector.empty) >> head
        }
        ConnectNewHeads connectNewHeads = new ConnectNewHeads(up, Schedulers.boundedElastic())
--- a/src/test/groovy/io/emeraldpay/dshackle/upstream/grpc/EthereumGrpcUpstreamSpec.groovy
+++ b/src/test/groovy/io/emeraldpay/dshackle/upstream/grpc/EthereumGrpcUpstreamSpec.groovy
@@ -1,264 +0,0 @@
-/**
- * Copyright (c) 2019 ETCDEV GmbH
- * Copyright (c) 2020 EmeraldPay, Inc
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *        http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.emeraldpay.dshackle.upstream.grpc
-
-import com.fasterxml.jackson.databind.ObjectMapper
-import com.google.protobuf.ByteString
-import io.emeraldpay.api.proto.BlockchainGrpc
-import io.emeraldpay.api.proto.BlockchainOuterClass
-import io.emeraldpay.api.proto.Common
-import io.emeraldpay.dshackle.Chain
-import io.emeraldpay.dshackle.Global
-import io.emeraldpay.dshackle.config.ChainsConfig
-import io.emeraldpay.dshackle.config.UpstreamsConfig
-import io.emeraldpay.dshackle.data.BlockId
-import io.emeraldpay.dshackle.test.MockGrpcServer
-import io.emeraldpay.dshackle.test.TestingCommons
-import io.emeraldpay.dshackle.upstream.BuildInfo
-import io.emeraldpay.dshackle.upstream.UpstreamAvailability
-import io.emeraldpay.dshackle.upstream.ethereum.json.BlockJson
-import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcGrpcClient
-import io.emeraldpay.dshackle.upstream.rpcclient.RpcMetrics
-import io.emeraldpay.etherjar.domain.BlockHash
-import io.grpc.stub.StreamObserver
-import io.micrometer.core.instrument.Counter
-import io.micrometer.core.instrument.Timer
-import reactor.core.scheduler.Schedulers
-import spock.lang.Specification
-
-import java.time.Duration
-import java.time.Instant
-import java.util.concurrent.CompletableFuture
-
-class EthereumGrpcUpstreamSpec extends Specification {
-
-    MockGrpcServer mockServer = new MockGrpcServer()
-    ObjectMapper objectMapper = Global.objectMapper
-    RpcMetrics metrics = new RpcMetrics(
-            Timer.builder("test1").register(TestingCommons.meterRegistry),
-            Counter.builder("test2").register(TestingCommons.meterRegistry)
-    )
-    BlockHash parent = BlockHash.from("0x50d26e119968e791970d84a7bf5d0ec474d3ec2ef85d5ec8915210ac6bc09ad7")
-
-    def hash = (byte)123
-    def buildInfo = new BuildInfo("v0.0.1-test")
-
-    def "Subscribe to head"() {
-        setup:
-        def callData = [:]
-        def chain = Chain.ETHEREUM__MAINNET
-        def api = TestingCommons.api()
-        def block1 = new BlockJson().with {
-            it.number = 650246
-            it.hash = BlockHash.from("0x50d26e119968e791970d84a7bf5d0ec474d3ec2ef85d5ec8915210ac6bc09ad7")
-            it.totalDifficulty = new BigInteger("35bbde5595de6456", 16)
-            it.timestamp = Instant.now()
-            it.parentHash = parent
-            return it
-        }
-        api.answer("eth_getBlockByHash", [block1.hash.toHex(), false], block1)
-        def client = mockServer.clientForServer(new BlockchainGrpc.BlockchainImplBase() {
-            @Override
-            void nativeCall(BlockchainOuterClass.NativeCallRequest request, StreamObserver<BlockchainOuterClass.NativeCallReplyItem> responseObserver) {
-                api.nativeCall(request, responseObserver)
-            }
-
-            @Override
-            void subscribeHead(Common.Chain request, StreamObserver<BlockchainOuterClass.ChainHead> responseObserver) {
-                callData.chain = request.getTypeValue()
-                responseObserver.onNext(
-                        BlockchainOuterClass.ChainHead.newBuilder()
-                                .setBlockId(block1.hash.toHex().substring(2))
-                                .setHeight(block1.number)
-                                .setParentBlockId(parent.toHex().substring(2))
-                                .setWeight(ByteString.copyFrom(block1.totalDifficulty.toByteArray()))
-                                .build()
-                )
-            }
-        })
-        def upstream = new EthereumGrpcUpstream("test", hash, UpstreamsConfig.UpstreamRole.PRIMARY, chain, client, new JsonRpcGrpcClient(client, chain, metrics), null, ChainsConfig.ChainConfig.default(), Schedulers.boundedElastic())
-        upstream.setLag(0)
-        upstream.update(
-                BlockchainOuterClass.DescribeChain.newBuilder()
-                        .setStatus(BlockchainOuterClass.ChainStatus.newBuilder().setQuorum(1).setAvailabilityValue(UpstreamAvailability.OK.grpcId))
-                        .addAllSupportedMethods(["eth_getBlockByHash"])
-                        .build(),
-                BlockchainOuterClass.BuildInfo.newBuilder()
-                        .setVersion(buildInfo.version)
-                        .build(),
-        )
-        when:
-        new Thread({ Thread.sleep(50); upstream.head.start() }).start()
-        def h = upstream.head.getFlux().next().block(Duration.ofSeconds(1))
-        then:
-        callData.chain == Chain.ETHEREUM__MAINNET.id
-        upstream.status == UpstreamAvailability.OK
-        upstream.getBuildInfo() == buildInfo
-        h.hash == BlockId.from("0x50d26e119968e791970d84a7bf5d0ec474d3ec2ef85d5ec8915210ac6bc09ad7")
-    }
-
-    def "Follows difficulty, ignores less difficult"() {
-        setup:
-        def api = TestingCommons.api()
-        def block1 = new BlockJson().with {
-            it.number = 650246
-            it.hash = BlockHash.from("0x50d26e119968e791970d84a7bf5d0ec474d3ec2ef85d5ec8915210ac6bc09ad7")
-            it.totalDifficulty = new BigInteger("35bbde5595de6456", 16)
-            it.timestamp = Instant.now()
-            it.parentHash = parent
-            return it
-        }
-        def block2 = new BlockJson().with {
-            it.number = 650247
-            it.hash = BlockHash.from("0x3ec2ebf5d0ec474d0ac6bc50d2770d8409ad76e119968e7919f85d5ec891521a")
-            it.totalDifficulty = new BigInteger("35bbde5595de6455", 16)
-            it.timestamp = Instant.now()
-            it.parentHash = parent
-            return it
-        }
-        api.answer("eth_getBlockByHash", [block1.hash.toHex(), false], block1)
-        api.answer("eth_getBlockByHash", [block2.hash.toHex(), false], block2)
-        def client = mockServer.clientForServer(new BlockchainGrpc.BlockchainImplBase() {
-            @Override
-            void nativeCall(BlockchainOuterClass.NativeCallRequest request, StreamObserver<BlockchainOuterClass.NativeCallReplyItem> responseObserver) {
-                api.nativeCall(request, responseObserver)
-            }
-
-            @Override
-            void subscribeHead(Common.Chain request, StreamObserver<BlockchainOuterClass.ChainHead> responseObserver) {
-                new Thread({
-                    responseObserver.onNext(
-                            BlockchainOuterClass.ChainHead.newBuilder()
-                                    .setBlockId(block1.hash.toHex().substring(2))
-                                    .setHeight(block1.number)
-                                    .setParentBlockId(parent.toHex().substring(2))
-                                    .setWeight(ByteString.copyFrom(block1.totalDifficulty.toByteArray()))
-                                    .build()
-                    )
-                    Thread.sleep(100)
-                    responseObserver.onNext(
-                            BlockchainOuterClass.ChainHead.newBuilder()
-                                    .setBlockId(block2.hash.toHex().substring(2))
-                                    .setHeight(block2.number)
-                                    .setParentBlockId(parent.toHex().substring(2))
-                                    .setWeight(ByteString.copyFrom(block2.totalDifficulty.toByteArray()))
-                                    .build()
-                    )
-                }).start()
-            }
-        })
-        def upstream = new EthereumGrpcUpstream("test", hash, UpstreamsConfig.UpstreamRole.PRIMARY, Chain.ETHEREUM__MAINNET, client, new JsonRpcGrpcClient(client, Chain.ETHEREUM__MAINNET, metrics), null, ChainsConfig.ChainConfig.default(), Schedulers.boundedElastic())
-        upstream.setLag(0)
-        upstream.update(
-                BlockchainOuterClass.DescribeChain.newBuilder()
-                        .setStatus(BlockchainOuterClass.ChainStatus.newBuilder().setQuorum(1).setAvailabilityValue(UpstreamAvailability.OK.grpcId))
-                        .addAllSupportedMethods(["eth_getBlockByHash"])
-                        .build(),
-                BlockchainOuterClass.BuildInfo.newBuilder()
-                        .setVersion(buildInfo.version)
-                        .build(),
-        )
-        when:
-        new Thread({ Thread.sleep(50); upstream.head.start() }).start()
-        def h = upstream.head.getFlux().take(Duration.ofSeconds(1)).last().block(Duration.ofSeconds(2))
-        then:
-        upstream.status == UpstreamAvailability.OK
-        upstream.getBuildInfo() == buildInfo
-        h.hash == BlockId.from("0x50d26e119968e791970d84a7bf5d0ec474d3ec2ef85d5ec8915210ac6bc09ad7")
-        h.height == 650246
-    }
-
-    def "Follows difficulty"() {
-        setup:
-        def callData = [:]
-        def finished = new CompletableFuture<Boolean>()
-        def chain = Chain.ETHEREUM__MAINNET
-        def api = TestingCommons.api()
-        def block1 = new BlockJson().with {
-            it.number = 650246
-            it.hash = BlockHash.from("0x50d26e119968e791970d84a7bf5d0ec474d3ec2ef85d5ec8915210ac6bc09ad7")
-            it.totalDifficulty = new BigInteger("35bbde5595de6456", 16)
-            it.timestamp = Instant.now()
-            it.parentHash = parent
-            return it
-        }
-        def block2 = new BlockJson().with {
-            it.number = 650247
-            it.hash = BlockHash.from("0x3ec2ebf5d0ec474d0ac6bc50d2770d8409ad76e119968e7919f85d5ec891521a")
-            it.totalDifficulty = new BigInteger("35bbde5595de6457", 16)
-            it.timestamp = Instant.now()
-            it.parentHash = parent
-            return it
-        }
-        api.answer("eth_getBlockByHash", [block1.hash.toHex(), false], block1)
-        api.answer("eth_getBlockByHash", [block2.hash.toHex(), false], block2)
-        def client = mockServer.clientForServer(new BlockchainGrpc.BlockchainImplBase() {
-            @Override
-            void nativeCall(BlockchainOuterClass.NativeCallRequest request, StreamObserver<BlockchainOuterClass.NativeCallReplyItem> responseObserver) {
-                api.nativeCall(request, responseObserver)
-            }
-
-            @Override
-            void subscribeHead(Common.Chain request, StreamObserver<BlockchainOuterClass.ChainHead> responseObserver) {
-                responseObserver.onNext(
-                        BlockchainOuterClass.ChainHead.newBuilder()
-                                .setBlockId(block1.hash.toHex().substring(2))
-                                .setHeight(block1.number)
-                                .setParentBlockId(parent.toHex().substring(2))
-                                .setWeight(ByteString.copyFrom(block1.totalDifficulty.toByteArray()))
-                                .build()
-                )
-                responseObserver.onNext(
-                        BlockchainOuterClass.ChainHead.newBuilder()
-                                .setBlockId(block2.hash.toHex().substring(2))
-                                .setHeight(block2.number)
-                                .setParentBlockId(parent.toHex().substring(2))
-                                .setWeight(ByteString.copyFrom(block2.totalDifficulty.toByteArray()))
-                                .build()
-                )
-                finished.complete(true)
-            }
-        })
-        def upstream = new EthereumGrpcUpstream("test", hash, UpstreamsConfig.UpstreamRole.PRIMARY, chain, client, new JsonRpcGrpcClient(client, chain, metrics), null, ChainsConfig.ChainConfig.default(), Schedulers.boundedElastic())
-        upstream.setLag(0)
-        upstream.update(
-                BlockchainOuterClass.DescribeChain.newBuilder()
-                        .setStatus(BlockchainOuterClass.ChainStatus.newBuilder().setQuorum(1).setAvailabilityValue(UpstreamAvailability.OK.grpcId))
-                        .addAllSupportedMethods(["eth_getBlockByHash"])
-                        .build(),
-                BlockchainOuterClass.BuildInfo.newBuilder()
-                        .setVersion(buildInfo.version)
-                        .build(),
-        )
-        when:
-        new Thread({ Thread.sleep(50); upstream.head.start() }).start()
-        finished.get()
-        def h = upstream.head.getFlux().take(Duration.ofSeconds(1)).last().block(Duration.ofSeconds(2))
-        then:
-        upstream.status == UpstreamAvailability.OK
-        upstream.getBuildInfo() == buildInfo
-        h.hash == BlockId.from("0x3ec2ebf5d0ec474d0ac6bc50d2770d8409ad76e119968e7919f85d5ec891521a")
-        h.height == 650247
-    }
-
-    private BlockchainOuterClass.DescribeChain describe(List<String> methods) {
-        return BlockchainOuterClass.DescribeChain.newBuilder()
-                .setStatus(BlockchainOuterClass.ChainStatus.newBuilder().setQuorum(1).setAvailabilityValue(UpstreamAvailability.OK.grpcId))
-                .addAllSupportedMethods(methods)
-                .build()
-    }
-}