solution: switch to Etherjar 0.7

gradle.properties

@@ -14,7 +14,7 @@ springBootVersion=2.1.4.RELEASE
 springVersion=5.1.4.RELEASE
 
 # Our Libs
-etherjarVersion=0.6.0
+etherjarVersion=0.7.0-SNAPSHOT
 
 # Testing
 spockVersion=1.2-groovy-2.5

src/main/kotlin/io/emeraldpay/dshackle/upstream/EthereumUpstream.kt

@@ -1,24 +1,52 @@
 package io.emeraldpay.dshackle.upstream
 
 import com.fasterxml.jackson.databind.ObjectMapper
+import io.infinitape.etherjar.rpc.RpcCall
+import io.infinitape.etherjar.rpc.RpcClient
+import io.infinitape.etherjar.rpc.RpcException
+import io.infinitape.etherjar.rpc.RpcResponseError
 import io.infinitape.etherjar.rpc.json.ResponseJson
-import io.infinitape.etherjar.rpc.transport.RpcTransport
+import org.slf4j.LoggerFactory
 import reactor.core.publisher.Mono
+import java.time.Duration
 
 class EthereumUpstream(
-        private val rpcTransport: RpcTransport,
+        private val rpcClient: RpcClient,
         private val objectMapper: ObjectMapper
 ) {
 
+    private val timeout = Duration.ofSeconds(5)
+    private val log = LoggerFactory.getLogger(EthereumUpstream::class.java)
+
     fun execute(id: Int, method: String, params: List<Any>): Mono<ByteArray> {
         return Mono
-                .fromCompletionStage(rpcTransport.execute(method, params, Any::class.java))
+                .fromCompletionStage(
+                        rpcClient.execute(RpcCall.create(method, Any::class.java, params))
+                )
+                .timeout(timeout)
+                .doOnError { t ->
+                    log.warn("Upstream error: ${t.message}")
+                }
                 .map {
                     val resp = ResponseJson<Any, Int>()
                     resp.id = id
                     resp.result = it
                     objectMapper.writer().writeValueAsBytes(resp)
                 }
+                .onErrorMap { t ->
+                    if (RpcException::class.java.isAssignableFrom(t.javaClass)) {
+                        t
+                    } else {
+                        log.warn("Convert to RPC error. Exception: ${t.message}")
+                        RpcException(-32020, "Error reading from upstream", null, t)
+                    }
+                }
+                .onErrorResume(RpcException::class.java) { t ->
+                    val resp = ResponseJson<Any, Int>()
+                    resp.id = id
+                    resp.error = t.error
+                    Mono.just(objectMapper.writer().writeValueAsBytes(resp))
+                }
     }
 
 }

src/main/kotlin/io/emeraldpay/dshackle/upstream/Upstreams.kt

@@ -2,6 +2,7 @@ package io.emeraldpay.dshackle.upstream
 
 import com.fasterxml.jackson.databind.ObjectMapper
 import io.emeraldpay.grpc.Chain
+import io.infinitape.etherjar.rpc.DefaultRpcClient
 import io.infinitape.etherjar.rpc.transport.DefaultRpcTransport
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.core.env.Environment
@@ -33,7 +34,7 @@ class Upstreams(
 
     private fun buildClient(url: String): EthereumUpstream {
         return EthereumUpstream(
-                DefaultRpcTransport(URI(url)),
+                DefaultRpcClient(DefaultRpcTransport(URI(url))),
                 objectMapper
         )
     }