Merge pull request #162 from corda/aslemmer-fix-netty-buffer-leak

Aslemmer fix netty buffer leak

experimental/flow-hook/src/main/kotlin/net/corda/flowhook/FiberMonitor.kt

@@ -2,19 +2,14 @@ package net.corda.flowhook
 
 import co.paralleluniverse.fibers.Fiber
 import net.corda.core.internal.uncheckedCast
-import net.corda.core.utilities.contextLogger
+import net.corda.core.utilities.loggerFor
 import net.corda.nodeapi.internal.persistence.DatabaseTransaction
 import java.sql.Connection
 import java.time.Instant
-import java.util.concurrent.LinkedBlockingQueue
+import java.util.concurrent.Executors
+import java.util.concurrent.ScheduledExecutorService
 import java.util.concurrent.TimeUnit
 import java.util.concurrent.atomic.AtomicBoolean
-import kotlin.concurrent.thread
-
-/**
- * This is a debugging helper class that dumps the map of Fiber->DB connection, or more precisely, the
- * Fiber->(DB tx -> DB connection) map, as there may be multiple transactions per fiber.
- */
 
 data class MonitorEvent(val type: MonitorEventType, val keys: List<Any>, val extra: Any? = null)
 
@@ -34,47 +29,62 @@ enum class MonitorEventType {
     FiberResumed,
     FiberEnded,
 
-    ExecuteTransition
+    SmExecuteTransition,
+    SmScheduleEvent,
+
+    NettyThreadLocalMapCreated,
+
+    SetThreadLocals,
+    SetInheritableThreadLocals,
+    GetThreadLocals,
+    GetInheritableThreadLocals
 }
 
+/**
+ * This is a monitor processing events coming from [FlowHookContainer]. It just appends them to a log that allows
+ * analysis of the events.
+ *
+ * Suggested way of debugging using this class and IntelliJ:
+ * 1. Hook the function calls you're interested in using [FlowHookContainer].
+ * 2. Add an associated event type in [MonitorEventType].
+ * 3. Call [newEvent] in the hook. Provide some keys to allow analysis. Example keys are the current fiber ID or a
+ *   specific DB transaction. You can also provide additional info about the event using [MonitorEvent.extra].
+ * 4. Run your test and break on [newEvent] or [inspect].
+ * 5. Inspect the [correlator] in the debugger. E.g. you can add a watch for [MonitorEventCorrelator.getByType].
+ *   You can search for specific objects by using filter expressions in the debugger.
+ */
 object FiberMonitor {
-    private val log = contextLogger()
+    private val log = loggerFor<FiberMonitor>()
-    private val jobQueue = LinkedBlockingQueue<Job>()
     private val started = AtomicBoolean(false)
-    private var trackerThread: Thread? = null
+    private var executor: ScheduledExecutorService? = null
 
     val correlator = MonitorEventCorrelator()
 
-    sealed class Job {
-        data class NewEvent(val event: FullMonitorEvent) : Job()
-        object Finish : Job()
-    }
-
     fun newEvent(event: MonitorEvent) {
-        if (trackerThread != null) {
+        if (executor != null) {
-            jobQueue.add(Job.NewEvent(FullMonitorEvent(Instant.now(), Exception().stackTrace.toList(), event)))
+            val fullEvent = FullMonitorEvent(Instant.now(), Exception().stackTrace.toList(), event)
+            executor!!.execute {
+                processEvent(fullEvent)
+            }
         }
     }
 
     fun start() {
         if (started.compareAndSet(false, true)) {
-            require(trackerThread == null)
+            require(executor == null)
-            trackerThread = thread(name = "Fiber monitor", isDaemon = true) {
+            executor = Executors.newSingleThreadScheduledExecutor()
-                while (true) {
+            executor!!.scheduleAtFixedRate(this::inspect, 100, 100, TimeUnit.MILLISECONDS)
-                    val job = jobQueue.poll(1, TimeUnit.SECONDS)
-                    when (job) {
-                        is Job.NewEvent -> processEvent(job)
-                        Job.Finish -> return@thread
-                    }
-                }
-            }
         }
     }
 
-    private fun processEvent(job: Job.NewEvent) {
+    // Break on this function or [newEvent].
-        correlator.addEvent(job.event)
+    private fun inspect() {
-        checkLeakedTransactions(job.event.event)
+    }
-        checkLeakedConnections(job.event.event)
+
+    private fun processEvent(event: FullMonitorEvent) {
+        correlator.addEvent(event)
+        checkLeakedTransactions(event.event)
+        checkLeakedConnections(event.event)
     }
 
     inline fun <reified R, A : Any> R.getField(name: String): A {
@@ -124,7 +134,7 @@ object FiberMonitor {
 
     private fun checkLeakedConnections(event: MonitorEvent) {
         if (event.type == MonitorEventType.FiberParking) {
-            val events = correlator.events[event.keys[0]]!!
+            val events = correlator.merged()[event.keys[0]]!!
             val acquiredConnections = events.mapNotNullTo(HashSet()) {
                 if (it.event.type == MonitorEventType.ConnectionAcquired) {
                     it.event.keys.mapNotNull { it as? Connection }.first()
@@ -147,35 +157,47 @@ object FiberMonitor {
     }
 }
 
+/**
+ * This class holds the event log.
+ *
+ * Each event has a list of key associated with it. "Relatedness" is then the transitive closure of two events sharing a key.
+ *
+ * [merged] returns a map from key to related events. Note that an eventlist may be associated by several keys.
+ * [getUnique] makes these lists unique by keying on the set of keys associated with the events.
+ * [getByType] simply groups by the type of the keys. This is probably the most useful "top-level" breakdown of events.
+ */
 class MonitorEventCorrelator {
-    private val _events = HashMap<Any, ArrayList<FullMonitorEvent>>()
+    private val events = ArrayList<FullMonitorEvent>()
-    val events: Map<Any, ArrayList<FullMonitorEvent>> get() = _events
 
-    fun getUnique() = events.values.toSet().associateBy { it.flatMap { it.event.keys }.toSet() }
+    fun getUnique() = merged().values.toSet().associateBy { it.flatMap { it.event.keys }.toSet() }
 
-    fun getByType() = events.entries.groupBy { it.key.javaClass }
+    fun getByType() = merged().entries.groupBy { it.key.javaClass }
 
     fun addEvent(fullMonitorEvent: FullMonitorEvent) {
-        val list = link(fullMonitorEvent.event.keys)
+        events.add(fullMonitorEvent)
-        list.add(fullMonitorEvent)
-        for (key in fullMonitorEvent.event.keys) {
-            _events[key] = list
-        }
     }
 
-    fun link(keys: List<Any>): ArrayList<FullMonitorEvent> {
+    fun merged(): Map<Any, List<FullMonitorEvent>> {
+        val merged = HashMap<Any, ArrayList<FullMonitorEvent>>()
+        for (event in events) {
             val eventLists = HashSet<ArrayList<FullMonitorEvent>>()
-        for (key in keys) {
+            for (key in event.event.keys) {
-            val list = _events[key]
+                val list = merged[key]
                 if (list != null) {
                     eventLists.add(list)
                 }
             }
-        return when {
+            val newList = when (eventLists.size) {
-            eventLists.isEmpty() -> ArrayList()
+                0 -> ArrayList()
-            eventLists.size == 1 -> eventLists.first()
+                1 -> eventLists.first()
                 else -> mergeAll(eventLists)
             }
+            newList.add(event)
+            for (key in event.event.keys) {
+                merged[key] = newList
+            }
+        }
+        return merged
     }
 
     fun mergeAll(lists: Collection<List<FullMonitorEvent>>): ArrayList<FullMonitorEvent> {

experimental/flow-hook/src/main/kotlin/net/corda/flowhook/FlowHookContainer.kt

@@ -1,14 +1,8 @@
 package net.corda.flowhook
 
 import co.paralleluniverse.fibers.Fiber
-import net.corda.node.services.statemachine.ActionExecutor
 import net.corda.node.services.statemachine.Event
-import net.corda.node.services.statemachine.FlowFiber
-import net.corda.node.services.statemachine.StateMachineState
-import net.corda.node.services.statemachine.transitions.TransitionResult
-import net.corda.nodeapi.internal.persistence.CordaPersistence
 import net.corda.nodeapi.internal.persistence.DatabaseTransactionManager
-import rx.subjects.Subject
 import java.sql.Connection
 
 @Suppress("UNUSED")
@@ -26,6 +20,12 @@ object FlowHookContainer {
         FiberMonitor.newEvent(MonitorEvent(MonitorEventType.FiberStarted, keys = listOf(Fiber.currentFiber())))
     }
 
+    @JvmStatic
+    @Hook("net.corda.node.services.statemachine.FlowStateMachineImpl", passThis = true)
+    fun scheduleEvent(fiber: Any, event: Event) {
+        FiberMonitor.newEvent(MonitorEvent(MonitorEventType.SmScheduleEvent, keys = listOf(fiber), extra = listOf(event, currentFiberOrThread())))
+    }
+
     @JvmStatic
     @Hook("co.paralleluniverse.fibers.Fiber")
     fun onCompleted() {
@@ -45,13 +45,13 @@ object FlowHookContainer {
     }
 
     @JvmStatic
-    @Hook("net.corda.node.utilities.DatabaseTransaction", passThis = true, position = HookPosition.After)
+    @Hook("net.corda.nodeapi.internal.persistence.DatabaseTransaction", passThis = true, position = HookPosition.After)
     fun DatabaseTransaction(
             transaction: Any,
             isolation: Int,
-            threadLocal: ThreadLocal<*>,
+            threadLocal: Any,
-            transactionBoundaries: Subject<*, *>,
+            transactionBoundaries: Any,
-            cordaPersistence: CordaPersistence
+            cordaPersistence: Any
     ) {
         val keys = ArrayList<Any>().apply {
             add(transaction)
@@ -60,9 +60,65 @@ object FlowHookContainer {
         FiberMonitor.newEvent(MonitorEvent(MonitorEventType.TransactionCreated, keys = keys))
     }
 
+    @JvmStatic
+    @Hook("io.netty.util.internal.InternalThreadLocalMap", passThis = true, position = HookPosition.After)
+    fun InternalThreadLocalMap(
+            internalThreadLocalMap: Any
+    ) {
+        val keys = listOf(
+                internalThreadLocalMap,
+                currentFiberOrThread()
+        )
+        FiberMonitor.newEvent(MonitorEvent(MonitorEventType.NettyThreadLocalMapCreated, keys = keys))
+    }
+
+    @JvmStatic
+    @Hook("co.paralleluniverse.concurrent.util.ThreadAccess")
+    fun setThreadLocals(thread: Thread, threadLocals: Any?) {
+        FiberMonitor.newEvent(MonitorEvent(
+                MonitorEventType.SetThreadLocals,
+                keys = listOf(currentFiberOrThread()),
+                extra = threadLocals?.let { FiberMonitor.getThreadLocalMapEntryValues(it) }
+        ))
+    }
+
+    @JvmStatic
+    @Hook("co.paralleluniverse.concurrent.util.ThreadAccess")
+    fun setInheritableThreadLocals(thread: Thread, threadLocals: Any?) {
+        FiberMonitor.newEvent(MonitorEvent(
+                MonitorEventType.SetInheritableThreadLocals,
+                keys = listOf(currentFiberOrThread()),
+                extra = threadLocals?.let { FiberMonitor.getThreadLocalMapEntryValues(it) }
+        ))
+    }
+
+    @JvmStatic
+    @Hook("co.paralleluniverse.concurrent.util.ThreadAccess")
+    fun getThreadLocals(thread: Thread): (threadLocals: Any?) -> Unit {
+        return { threadLocals ->
+            FiberMonitor.newEvent(MonitorEvent(
+                    MonitorEventType.GetThreadLocals,
+                    keys = listOf(currentFiberOrThread()),
+                    extra = threadLocals?.let { FiberMonitor.getThreadLocalMapEntryValues(it) }
+            ))
+        }
+    }
+
+    @JvmStatic
+    @Hook("co.paralleluniverse.concurrent.util.ThreadAccess")
+    fun getInheritableThreadLocals(thread: Thread): (threadLocals: Any?) -> Unit {
+        return { threadLocals ->
+            FiberMonitor.newEvent(MonitorEvent(
+                    MonitorEventType.GetInheritableThreadLocals,
+                    keys = listOf(currentFiberOrThread()),
+                    extra = threadLocals?.let { FiberMonitor.getThreadLocalMapEntryValues(it) }
+            ))
+        }
+    }
+
     @JvmStatic
     @Hook("com.zaxxer.hikari.HikariDataSource")
-    fun getConnection(): (Connection) -> Unit {
+    fun getConnection(): (Any) -> Unit {
         val transactionOrThread = currentTransactionOrThread()
         FiberMonitor.newEvent(MonitorEvent(MonitorEventType.ConnectionRequested, keys = listOf(transactionOrThread)))
         return { connection ->
@@ -81,19 +137,23 @@ object FlowHookContainer {
     @JvmStatic
     @Hook("net.corda.node.services.statemachine.TransitionExecutorImpl")
     fun executeTransition(
-            fiber: FlowFiber,
+            fiber: Any,
-            previousState: StateMachineState,
+            previousState: Any,
-            event: Event,
+            event: Any,
-            transition: TransitionResult,
+            transition: Any,
-            actionExecutor: ActionExecutor
+            actionExecutor: Any
     ) {
-        FiberMonitor.newEvent(MonitorEvent(MonitorEventType.ExecuteTransition, keys = listOf(fiber), extra = object {
+        FiberMonitor.newEvent(MonitorEvent(MonitorEventType.SmExecuteTransition, keys = listOf(fiber), extra = object {
             val previousState = previousState
             val event = event
             val transition = transition
         }))
     }
 
+    private fun currentFiberOrThread(): Any {
+        return Fiber.currentFiber() ?: Thread.currentThread()
+    }
+
     private fun currentTransactionOrThread(): Any {
         return try {
             DatabaseTransactionManager.currentOrNull()

experimental/flow-hook/src/main/kotlin/net/corda/flowhook/Hooker.kt

@@ -56,28 +56,36 @@ class Hooker(hookContainer: Any) : ClassFileTransformer {
     private fun instrumentClass(clazz: CtClass): CtClass? {
         val hookMethods = hooks[clazz.name] ?: return null
         val usedHookMethods = HashSet<Method>()
-        var isAnyInstrumented = false
         for (method in clazz.declaredBehaviors) {
-            val hookMethod = instrumentBehaviour(method, hookMethods)
+            usedHookMethods.addAll(instrumentBehaviour(method, hookMethods))
-            if (hookMethod != null) {
-                isAnyInstrumented = true
-                usedHookMethods.add(hookMethod)
-            }
         }
         val unusedHookMethods = hookMethods.values.mapTo(HashSet()) { it.first } - usedHookMethods
+        if (usedHookMethods.isNotEmpty()) {
+            println("Hooked methods $usedHookMethods")
+        }
         if (unusedHookMethods.isNotEmpty()) {
             println("Unused hook methods $unusedHookMethods")
         }
-        return if (isAnyInstrumented) {
+        return if (usedHookMethods.isNotEmpty()) {
             clazz
         } else {
             null
         }
     }
 
-    private fun instrumentBehaviour(method: CtBehavior, methodHooks: MethodHooks): Method? {
+    private val objectName = Any::class.java.name
-        val signature = Signature(method.name, method.parameterTypes.map { it.name })
+    private fun instrumentBehaviour(method: CtBehavior, methodHooks: MethodHooks): List<Method> {
-        val (hookMethod, annotation) = methodHooks[signature] ?: return null
+        val pairs = methodHooks.mapNotNull { (signature, pair) ->
+            if (signature.functionName != method.name) return@mapNotNull null
+            if (signature.parameterTypes.size != method.parameterTypes.size) return@mapNotNull null
+            for (i in 0 until signature.parameterTypes.size) {
+                if (signature.parameterTypes[i] != objectName && signature.parameterTypes[i] != method.parameterTypes[i].name) {
+                    return@mapNotNull null
+                }
+            }
+            pair
+        }
+        for ((hookMethod, annotation) in pairs) {
             val invocationString = if (annotation.passThis) {
                 "${hookMethod.declaringClass.canonicalName}.${hookMethod.name}(this, \$\$)"
             } else {
@@ -99,19 +107,32 @@ class Hooker(hookContainer: Any) : ClassFileTransformer {
             when {
                 Function0::class.java.isAssignableFrom(hookMethod.returnType) -> {
                     method.addLocalVariable("after", classPool.get("kotlin.jvm.functions.Function0"))
-                method.insertHook("after = $invocationString;")
+                    method.insertHook("after = null; ${wrapTryCatch("after = $invocationString;")}")
-                method.insertAfter("after.invoke();")
+                    method.insertAfter("if (after != null) ${wrapTryCatch("after.invoke();")}")
                 }
                 Function1::class.java.isAssignableFrom(hookMethod.returnType) -> {
                     method.addLocalVariable("after", classPool.get("kotlin.jvm.functions.Function1"))
-                method.insertHook("after = $invocationString;")
+                    method.insertHook("after = null; ${wrapTryCatch("after = $invocationString;")}")
-                method.insertAfter("after.invoke((\$w)\$_);")
+                    method.insertAfter("if (after != null) ${wrapTryCatch("after.invoke((\$w)\$_);")}")
                 }
                 else -> {
-                method.insertHook("$invocationString;")
+                    method.insertHook(wrapTryCatch("$invocationString;"))
                 }
             }
-        return hookMethod
+        }
+        return pairs.map { it.first }
+    }
+
+    companion object {
+
+        fun wrapTryCatch(statement: String): String {
+            return "try { $statement } catch (Throwable throwable) { ${Hooker::class.java.canonicalName}.${Hooker.Companion::exceptionInHook.name}(throwable); }"
+        }
+
+        @JvmStatic
+        fun exceptionInHook(throwable: Throwable) {
+            throwable.printStackTrace()
+        }
     }
 }
 
@@ -122,7 +143,11 @@ enum class HookPosition {
 }
 
 @Target(AnnotationTarget.FUNCTION)
-annotation class Hook(val clazz: String, val position: HookPosition = HookPosition.Before, val passThis: Boolean = false)
+annotation class Hook(
+        val clazz: String,
+        val position: HookPosition = HookPosition.Before,
+        val passThis: Boolean = false
+)
 
 private data class Signature(val functionName: String, val parameterTypes: List<String>)
 

node/src/integration-test/kotlin/net/corda/node/NodePerformanceTests.kt

@@ -17,6 +17,7 @@ import net.corda.nodeapi.internal.config.User
 import net.corda.testing.DUMMY_NOTARY
 import net.corda.testing.*
 import net.corda.testing.driver.NodeHandle
+import net.corda.testing.driver.PortAllocation
 import net.corda.testing.driver.driver
 import net.corda.testing.internal.performance.div
 import net.corda.testing.internal.performance.startPublishingFixedRateInjector
@@ -128,21 +129,40 @@ class NodePerformanceTests : IntegrationTest() {
         driver(
                 notarySpecs = listOf(NotarySpec(DUMMY_NOTARY.name, rpcUsers = listOf(user))),
                 startNodesInProcess = true,
-                extraCordappPackagesToScan = listOf("net.corda.finance")
+                extraCordappPackagesToScan = listOf("net.corda.finance"),
+                portAllocation = PortAllocation.Incremental(20000)
         ) {
             val notary = defaultNotaryNode.getOrThrow() as NodeHandle.InProcess
             val metricRegistry = startReporter(shutdownManager, notary.node.services.monitoringService.metrics)
             notary.rpcClientToNode().use("A", "A") { connection ->
                 println("ISSUING")
-                val doneFutures = (1..100).toList().parallelStream().map {
+                val doneFutures = (1..100).toList().map {
                     connection.proxy.startFlow(::CashIssueFlow, 1.DOLLARS, OpaqueBytes.of(0), defaultNotaryIdentity).returnValue
                 }.toList()
                 doneFutures.transpose().get()
                 println("STARTING PAYMENT")
-                startPublishingFixedRateInjector(metricRegistry, 8, 5.minutes, 100L / TimeUnit.SECONDS) {
+                startPublishingFixedRateInjector(metricRegistry, 8, 5.minutes, 5L / TimeUnit.SECONDS) {
                     connection.proxy.startFlow(::CashPaymentFlow, 1.DOLLARS, defaultNotaryIdentity).returnValue.get()
                 }
             }
         }
     }
+
+    @Test
+    fun `single pay`() {
+        val user = User("A", "A", setOf(startFlow<CashIssueFlow>(), startFlow<CashPaymentFlow>()))
+        driver(
+                notarySpecs = listOf(NotarySpec(DUMMY_NOTARY.name, rpcUsers = listOf(user))),
+                startNodesInProcess = true,
+                extraCordappPackagesToScan = listOf("net.corda.finance"),
+                portAllocation = PortAllocation.Incremental(20000)
+        ) {
+            val notary = defaultNotaryNode.getOrThrow() as NodeHandle.InProcess
+            val metricRegistry = startReporter(shutdownManager, notary.node.services.monitoringService.metrics)
+            notary.rpcClientToNode().use("A", "A") { connection ->
+                connection.proxy.startFlow(::CashIssueFlow, 1.DOLLARS, OpaqueBytes.of(0), defaultNotaryIdentity).returnValue.getOrThrow()
+                connection.proxy.startFlow(::CashPaymentFlow, 1.DOLLARS, defaultNotaryIdentity).returnValue.getOrThrow()
+            }
+        }
+    }
 }

node/src/main/kotlin/net/corda/node/services/messaging/P2PMessagingClient.kt

@@ -294,12 +294,14 @@ class P2PMessagingClient(config: NodeConfiguration,
                     // processing a message but if so, it'll be parked waiting for us to count down the latch, so
                     // the session itself is still around and we can still ack messages as a result.
                     override fun acknowledge() {
+                        messagingExecutor.fetchFrom {
                             state.locked {
                                 artemisMessage.individualAcknowledge()
                                 artemis.started!!.session.commit()
                             }
                         }
                     }
+                }
                 deliverTo(msg, HandlerRegistration(msg.topic, deliverTo), acknowledgeHandle)
             } else {
                 log.warn("Received message ${msg.uniqueMessageId} for ${msg.topic} that doesn't have any registered handlers yet")

node/src/main/kotlin/net/corda/node/services/statemachine/interceptors/DumpHistoryOnErrorInterceptor.kt

@@ -6,6 +6,7 @@ import net.corda.core.utilities.contextLogger
 import net.corda.node.services.statemachine.*
 import net.corda.node.services.statemachine.transitions.FlowContinuation
 import net.corda.node.services.statemachine.transitions.TransitionResult
+import java.time.Instant
 import java.util.concurrent.ConcurrentHashMap
 
 /**
@@ -28,13 +29,16 @@ class DumpHistoryOnErrorInterceptor(val delegate: TransitionExecutor) : Transiti
             actionExecutor: ActionExecutor
     ): Pair<FlowContinuation, StateMachineState> {
         val (continuation, nextState) = delegate.executeTransition(fiber, previousState, event, transition, actionExecutor)
-        val transitionRecord = TransitionDiagnosticRecord(fiber.id, previousState, nextState, event, transition, continuation)
+        val transitionRecord = TransitionDiagnosticRecord(Instant.now(), fiber.id, previousState, nextState, event, transition, continuation)
         val record = records.compute(fiber.id) { _, record ->
             (record ?: ArrayList()).apply { add(transitionRecord) }
         }
 
         if (nextState.checkpoint.errorState is ErrorState.Errored) {
             log.warn("Flow ${fiber.id} dirtied, dumping all transitions:\n${record!!.joinToString("\n")}")
+            for (error in nextState.checkpoint.errorState.errors) {
+                log.warn("Flow ${fiber.id} error", error.exception)
+            }
         }
 
         if (transition.newState.isRemoved) {

node/src/main/kotlin/net/corda/node/services/statemachine/interceptors/PrintingInterceptor.kt

@@ -5,6 +5,7 @@ import net.corda.core.utilities.contextLogger
 import net.corda.node.services.statemachine.*
 import net.corda.node.services.statemachine.transitions.FlowContinuation
 import net.corda.node.services.statemachine.transitions.TransitionResult
+import java.time.Instant
 
 /**
  * This interceptor simply prints all state machine transitions. Useful for debugging.
@@ -23,7 +24,7 @@ class PrintingInterceptor(val delegate: TransitionExecutor) : TransitionExecutor
             actionExecutor: ActionExecutor
     ): Pair<FlowContinuation, StateMachineState> {
         val (continuation, nextState) = delegate.executeTransition(fiber, previousState, event, transition, actionExecutor)
-        val transitionRecord = TransitionDiagnosticRecord(fiber.id, previousState, nextState, event, transition, continuation)
+        val transitionRecord = TransitionDiagnosticRecord(Instant.now(), fiber.id, previousState, nextState, event, transition, continuation)
         log.info("Transition for flow ${fiber.id} $transitionRecord")
         return Pair(continuation, nextState)
     }

node/src/main/kotlin/net/corda/node/services/statemachine/interceptors/TransitionDiagnosticRecord.kt

@@ -6,12 +6,14 @@ import net.corda.node.services.statemachine.Event
 import net.corda.node.services.statemachine.StateMachineState
 import net.corda.node.services.statemachine.transitions.TransitionResult
 import net.corda.node.utilities.ObjectDiffer
+import java.time.Instant
 
 /**
  * This is a diagnostic record that stores information about a state machine transition and provides pretty printing
  * by diffing the two states.
  */
 data class TransitionDiagnosticRecord(
+        val timestamp: Instant,
         val flowId: StateMachineRunId,
         val previousState: StateMachineState,
         val nextState: StateMachineState,
@@ -26,6 +28,7 @@ data class TransitionDiagnosticRecord(
                 listOf(
                         "",
                         " --- Transition of flow $flowId ---",
+                        "  Timestamp: $timestamp",
                         "  Event: $event",
                         "  Actions: ",
                         "    ${transition.actions.joinToString("\n    ")}",