solution: [optionally] provide request/response value with access log

docs/reference-configuration.adoc

@@ -430,6 +430,12 @@ accessLog:
 | `false`
 | Enable/Disable Access logging
 
+| `include-messages`
+| `false`
+| Include request params and response result/error (i.e., a JSON) in access log.
+It's an expensive operation, use it for debugging only.
+Note that for errors it provides only error message, not the error response itself.
+
 | `filename`
 | `access_log.jsonl`
 | Path to the access log file

src/main/kotlin/io/emeraldpay/dshackle/config/AccessLogConfig.kt

@@ -1,7 +1,8 @@
 package io.emeraldpay.dshackle.config
 
 class AccessLogConfig(
-    val enabled: Boolean = false
+    val enabled: Boolean = false,
+    val includeMessages: Boolean = false
 ) {
 
     var filename: String = "./access_log.jsonl"

src/main/kotlin/io/emeraldpay/dshackle/config/AccessLogReader.kt

@@ -15,7 +15,8 @@ class AccessLogReader : YamlConfigReader(), ConfigReader<AccessLogConfig> {
             if (!enabled) {
                 AccessLogConfig.disabled()
             } else {
-                val config = AccessLogConfig(true)
+                val includeMessages = getValueAsBool(node, "include-messages") ?: false
+                val config = AccessLogConfig(true, includeMessages)
                 getValueAsString(node, "filename")?.let {
                     config.filename = it
                 }

src/main/kotlin/io/emeraldpay/dshackle/monitoring/accesslog/AccessLogWriter.kt

@@ -63,6 +63,9 @@ class AccessLogWriter(
         }
         log.info("Writing Access Log to ${filename.absolutePath}")
         scheduler.schedule(runner, START_SLEEP_MS, TimeUnit.MILLISECONDS)
+
+        //propagate current config to the Event Builder, so it knows which details to include
+        EventsBuilder.accessLogConfig = config
     }
 
     private fun flushRunner() {

src/main/kotlin/io/emeraldpay/dshackle/monitoring/accesslog/Events.kt

@@ -108,7 +108,9 @@ class Events {
         val succeed: Boolean,
         val rpcError: Int? = null,
         val payloadSizeBytes: Long,
-        val nativeCall: NativeCallItemDetails
+        val nativeCall: NativeCallItemDetails,
+        val responseBody: String? = null,
+        val errorMessage: String? = null
     ) : ChainBase(blockchain, "NativeCall", id, channel)
 
     @JsonInclude(JsonInclude.Include.NON_NULL)
@@ -120,7 +122,8 @@ class Events {
         // info about the initial request, that may include several native calls
         val request: StreamRequestDetails,
         val payloadSizeBytes: Long,
-        val nativeSubscribe: NativeSubscribeItemDetails
+        val nativeSubscribe: NativeSubscribeItemDetails,
+        val responseBody: String? = null,
     ) : ChainBase(blockchain, "NativeSubscribe", id, channel)
 
     @JsonInclude(JsonInclude.Include.NON_NULL)
@@ -159,7 +162,8 @@ class Events {
     data class NativeCallItemDetails(
         val method: String,
         val id: Int,
-        val payloadSizeBytes: Long
+        val payloadSizeBytes: Long,
+        val requestParams: String? = null
     )
 
     data class NativeCallReplyDetails(

src/main/kotlin/io/emeraldpay/dshackle/monitoring/accesslog/EventsBuilder.kt

@@ -17,6 +17,9 @@ package io.emeraldpay.dshackle.monitoring.accesslog
 
 import io.emeraldpay.api.proto.BlockchainOuterClass
 import io.emeraldpay.api.proto.Common
+import io.emeraldpay.dshackle.Global
+import io.emeraldpay.dshackle.config.AccessLogConfig
+import io.emeraldpay.dshackle.upstream.rpcclient.JsonRpcError
 import io.emeraldpay.grpc.Chain
 import io.grpc.Attributes
 import io.grpc.Grpc
@@ -36,6 +39,10 @@ class EventsBuilder {
 
     companion object {
         private val log = LoggerFactory.getLogger(EventsBuilder::class.java)
+
+        // A reference to the config for current _running instance_.
+        // Initialized by AccessLogWriter
+        var accessLogConfig: AccessLogConfig = AccessLogConfig.default()
     }
 
     interface StartingHttp2Request {
@@ -306,7 +313,10 @@ class EventsBuilder {
                     Events.NativeCallItemDetails(
                         item.method,
                         item.id,
-                        item.payload.size().toLong()
+                        item.payload.size().toLong(),
+                        if (accessLogConfig.includeMessages) {
+                            if (item.payload != null && !item.payload.isEmpty && item.payload.isValidUtf8) item.payload.toStringUtf8() else ""
+                        } else null
                     )
                 )
             }
@@ -323,7 +333,11 @@ class EventsBuilder {
                 nativeCall = item,
                 payloadSizeBytes = item.payloadSizeBytes,
                 id = UUID.randomUUID(),
-                channel = Events.Channel.GRPC
+                channel = Events.Channel.GRPC,
+                responseBody = if (accessLogConfig.includeMessages) {
+                    if (msg.payload != null && !msg.payload.isEmpty && msg.payload.isValidUtf8) msg.payload.toStringUtf8() else ""
+                } else null,
+                errorMessage = if (accessLogConfig.includeMessages) msg.errorMessage else null,
             )
         }
 
@@ -341,7 +355,13 @@ class EventsBuilder {
                 nativeCall = item,
                 payloadSizeBytes = item.payloadSizeBytes,
                 id = UUID.randomUUID(),
-                channel = channel
+                channel = channel,
+                responseBody = if (accessLogConfig.includeMessages) (reply.result?.let { String(it) } ?: "") else null,
+                errorMessage = if (accessLogConfig.includeMessages) {
+                    reply.error?.let {
+                        it.upstreamError?.message ?: it.message
+                    } ?: ""
+                } else null
             )
         }
     }
@@ -373,7 +393,8 @@ class EventsBuilder {
                 nativeSubscribe = item!!,
                 payloadSizeBytes = msg.payload?.size()?.toLong() ?: 0L,
                 id = UUID.randomUUID(),
-                channel = Events.Channel.GRPC
+                channel = Events.Channel.GRPC,
+                responseBody = if (accessLogConfig.includeMessages) (msg.payload?.toStringUtf8() ?: "") else null,
             )
         }
     }

src/test/groovy/io/emeraldpay/dshackle/monitoring/accesslog/AccessLogWriterSpec.groovy

@@ -17,7 +17,7 @@ class AccessLogWriterSpec extends Specification {
         File accessLog = new File(dir, "accesslog.jsonl")
         println("Write access log to $accessLog.absolutePath")
         MainConfig config = new MainConfig()
-        config.accessLogConfig = new AccessLogConfig(true).tap {
+        config.accessLogConfig = new AccessLogConfig(true, false).tap {
             it.filename = accessLog.absolutePath
         }
         AccessLogWriter logWriter = new AccessLogWriter(config)