problem: unnecessary exceptions in logs when an unavailable blockchain is requested

src/main/kotlin/io/emeraldpay/dshackle/SilentException.kt

@@ -0,0 +1,17 @@
+package io.emeraldpay.dshackle
+
+import io.emeraldpay.grpc.Chain
+
+/**
+ * Exception that should be handled/logged without a stacktrace in production
+ */
+open class SilentException(message: String) : Exception(message) {
+
+
+    /**
+     * Blockchain is not available or not supported by current instance of the Dshackle
+     */
+    class UnsupportedBlockchain(val blockchainId: Int): SilentException("Unsupported blockchain $blockchainId") {
+        constructor(chain: Chain) : this(chain.id)
+    }
+}

src/main/kotlin/io/emeraldpay/dshackle/rpc/NativeCall.kt

@@ -18,6 +18,7 @@ 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.dshackle.SilentException
 import io.emeraldpay.dshackle.upstream.*
 import io.emeraldpay.dshackle.quorum.AlwaysQuorum
 import io.emeraldpay.dshackle.quorum.CallQuorum
@@ -81,10 +82,10 @@ class NativeCall(
     fun prepareCall(request: BlockchainOuterClass.NativeCallRequest): Flux<CallContext<RawCallDetails>> {
         val chain = Chain.byId(request.chain.number)
         if (chain == Chain.UNSPECIFIED) {
-            return Flux.error(CallFailure(0, Exception("Invalid chain id: ${request.chain.number}")))
+            return Flux.error(CallFailure(0, SilentException.UnsupportedBlockchain(request.chain.number)))
         }
         val upstream = upstreams.getUpstream(chain)
-                ?: return Flux.error(CallFailure(0, Exception("Chain ${chain.id} is unavailable")))
+                ?: return Flux.error(CallFailure(0, SilentException.UnsupportedBlockchain(chain)))
 
         return prepareCall(request, upstream)
     }

src/main/kotlin/io/emeraldpay/dshackle/rpc/TrackAddress.kt

@@ -18,6 +18,7 @@ package io.emeraldpay.dshackle.rpc
 import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.api.proto.Common
 import io.emeraldpay.dshackle.Defaults
+import io.emeraldpay.dshackle.SilentException
 import io.emeraldpay.dshackle.upstream.Selector
 import io.emeraldpay.dshackle.upstream.Upstreams
 import io.emeraldpay.grpc.Chain
@@ -34,7 +35,6 @@ import reactor.core.publisher.Mono
 import reactor.core.publisher.TopicProcessor
 import reactor.core.publisher.toFlux
 import reactor.core.scheduler.Scheduler
-import java.lang.Exception
 import java.time.Duration
 import java.time.Instant
 import java.util.*
@@ -95,10 +95,10 @@ class TrackAddress(
     private fun initializeSimple(request: BlockchainOuterClass.BalanceRequest): Flux<SimpleAddress> {
         val chain = Chain.byId(request.asset.chainValue)
         if (!upstreams.isAvailable(chain)) {
-            return Flux.error(Exception("Unsupported chain ${request.asset.chainValue}"))
+            return Flux.error(SilentException.UnsupportedBlockchain(request.asset.chainValue))
         }
         if (request.asset.code?.toLowerCase() != "ether") {
-            return Flux.error(Exception("Unsupported asset ${request.asset.code}"))
+            return Flux.error(SilentException("Unsupported asset ${request.asset.code}"))
         }
         return when {
             request.address.addrTypeCase == Common.AnyAddress.AddrTypeCase.ADDRESS_SINGLE ->
@@ -133,8 +133,16 @@ class TrackAddress(
                             buildResponse(it)
                         }
                         Flux.merge(current, bus).doFinally { stopTracking(tracked) }
-                    }.doOnError { t ->
-                        log.warn("Failed to process subscription", t)
+                    }
+                    .doOnError { t ->
+                        if (t is SilentException) {
+                            if (t is SilentException.UnsupportedBlockchain) {
+                                log.warn("Unsupported blockchain: ${t.blockchainId}")
+                            }
+                            log.debug("Failed to process subscription", t)
+                        } else {
+                            log.warn("Failed to process subscription", t)
+                        }
                     }
         }
     }
@@ -167,7 +175,7 @@ class TrackAddress(
     }
 
     fun getBalance(addr: SimpleAddress): Mono<Wei> {
-        val up = upstreams.getUpstream(addr.chain) ?: return Mono.error(Exception("Unsupported chain: ${addr.chain}"))
+        val up = upstreams.getUpstream(addr.chain) ?: return Mono.error(SilentException.UnsupportedBlockchain(addr.chain))
         return up.getApi(Selector.empty)
                 .flatMap { api -> api.executeAndConvert(Commands.eth().getBalance(addr.address, BlockTag.LATEST)) }
                 .timeout(Defaults.timeout)

src/main/kotlin/io/emeraldpay/dshackle/rpc/TrackTx.kt

@@ -18,6 +18,7 @@ package io.emeraldpay.dshackle.rpc
 import com.google.protobuf.ByteString
 import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.api.proto.Common
+import io.emeraldpay.dshackle.SilentException
 import io.emeraldpay.dshackle.upstream.Selector
 import io.emeraldpay.dshackle.upstream.Upstream
 import io.emeraldpay.dshackle.upstream.Upstreams
@@ -142,7 +143,7 @@ class TrackTx(
     fun prepareTracking(request: BlockchainOuterClass.TxStatusRequest): TxDetails {
         val chain = Chain.byId(request.chainValue)
         if (!clients.containsKey(chain)) {
-            throw Exception("Unsupported blockchain: ${chain}")
+            throw SilentException.UnsupportedBlockchain(chain)
         }
         val bus = TopicProcessor.create<Notification>()
         val details = TxDetails(
@@ -208,7 +209,7 @@ class TrackTx(
 
     private fun loadWeight(tx: TxDetails): Mono<TxDetails> {
         val upstream = upstreams.getUpstream(tx.chain)
-                ?: return Mono.error(Exception("Unsupported blockchain: ${tx.chain}"))
+                ?: return Mono.error(SilentException.UnsupportedBlockchain(tx.chain))
         return upstream.getApi(Selector.empty)
                 .flatMap { api -> api.executeAndConvert(Commands.eth().getBlock(tx.status.blockHash)) }
                 .map { block ->
@@ -249,7 +250,7 @@ class TrackTx(
 
     private fun checkForUpdate(tx: TxDetails): Mono<TxDetails> {
         val initialStatus = tx.status
-        val upstream = upstreams.getUpstream(tx.chain) ?: return Mono.error(Exception("Unsupported blockchain: ${tx.chain}"))
+        val upstream = upstreams.getUpstream(tx.chain) ?: return Mono.error(SilentException.UnsupportedBlockchain(tx.chain))
         val execution = upstream.getApi(Selector.empty)
                 .flatMap { api -> api.executeAndConvert(Commands.eth().getTransaction(tx.txid)) }
         return execution