[ETCM-739] Refactor BlockFetcher

Change BlockFetcher to typed actor

Split fetcher message handling among child actors

Abstract the fetch trait

Scalafmt

Refactor blockFetcherState

Author: AnastasiiaL

nix/overlay.nix

@@ -3,7 +3,7 @@ rev: final: prev: {
 
   mantis = final.callPackage ./mantis.nix {
     src = ../.;
-    depsSha256 = "sha256-0AeemKFcIU3eVGse8QQGauJeRsF7IgCLo5Yqu2FZsMs=";
+    depsSha256 = "sha256-US4L/xh2otnEfOa05bazb14bgYhQZpF4GfFY30sDkNY=";
   };
 
   mantis-hash = final.mantis.override {

project/Dependencies.scala

@@ -14,7 +14,9 @@ object Dependencies {
     Seq(
       "com.typesafe.akka" %% "akka-actor" % akkaVersion,
       "com.typesafe.akka" %% "akka-slf4j" % akkaVersion,
+      "com.typesafe.akka" %% "akka-actor-typed" % akkaVersion,
       "com.typesafe.akka" %% "akka-testkit" % akkaVersion,
+      "com.typesafe.akka" %% "akka-actor-testkit-typed" % akkaVersion,
       "com.typesafe.akka" %% "akka-stream" % akkaVersion,
       "com.miguno.akka" %% "akka-mock-scheduler" % "0.5.5" % "it,test"
     )

src/main/scala/io/iohk/ethereum/blockchain/sync/regular/BlockFetcher.scala

@@ -29,7 +29,6 @@ import scala.collection.immutable.Queue
   *                             - haven't fetched any yet
   *                             - are awaiting a response
   *                             - are awaiting a response but it should be ignored due to blocks being invalidated
-  * @param stateNodeFetcher
   * @param lastBlock
   * @param knownTop
   * @param blockProviders
@@ -41,17 +40,13 @@ case class BlockFetcherState(
     waitingHeaders: Queue[BlockHeader],
     fetchingHeadersState: FetchingHeadersState,
     fetchingBodiesState: FetchingBodiesState,
-    pausedFetching: Boolean = false,
-    stateNodeFetcher: Option[StateNodeFetcher],
     lastBlock: BigInt,
     knownTop: BigInt,
     blockProviders: Map[BigInt, PeerId]
 ) {
 
   def isFetching: Boolean = isFetchingHeaders || isFetchingBodies
 
-  def isFetchingStateNode: Boolean = stateNodeFetcher.isDefined
-
   private def hasEmptyBuffer: Boolean = readyBlocks.isEmpty && waitingHeaders.isEmpty
 
   def hasFetchedTopHeader: Boolean = nextBlockToFetch == knownTop + 1
@@ -88,31 +83,6 @@ case class BlockFetcherState(
         )
     })
 
-  def tryInsertBlock(block: Block, peerId: PeerId): Either[String, BlockFetcherState] = {
-    val blockHash = block.hash
-    if (isExist(blockHash)) {
-      Right(this)
-    } else if (isExistInReadyBlocks(block.header.parentHash)) {
-      val newState = clearQueues()
-        .copy(
-          readyBlocks = readyBlocks.takeWhile(_.number < block.number).enqueue(block)
-        )
-        .withPeerForBlocks(peerId, Seq(block.number))
-        .withKnownTopAt(block.number)
-      Right(newState)
-    } else if (isExistInWaitingHeaders(block.header.parentHash)) {
-      // ignore already requested bodies
-      val newFetchingBodiesState =
-        if (fetchingBodiesState == AwaitingBodies) AwaitingBodiesToBeIgnored else fetchingBodiesState
-      val newState = copy(
-        waitingHeaders = waitingHeaders.takeWhile(_.number < block.number).enqueue(block.header),
-        fetchingBodiesState = newFetchingBodiesState
-      )
-        .withKnownTopAt(block.number)
-      Right(newState)
-    } else Left(s"Cannot insert block [${ByteStringUtils.hash2string(blockHash)}] into the queues")
-  }
-
   /**
     * Validates received headers consistency and their compatibility with the state
     * TODO ETCM-370: This needs to be more fine-grained and detailed so blacklisting can be re-enabled
@@ -235,7 +205,9 @@ case class BlockFetcherState(
       .filter(_.headOption.exists(block => block.number <= lower))
       .filter(_.lastOption.exists(block => block.number >= upper))
       .filter(_.nonEmpty)
-      .map(blocks => (NonEmptyList(blocks.head, blocks.tail.toList), copy(readyBlocks = Queue())))
+      .map(blocks =>
+        (NonEmptyList(blocks.head, blocks.tail.toList), copy(readyBlocks = Queue(), lastBlock = blocks.last.number))
+      )
   }
 
   def clearQueues(): BlockFetcherState = {
@@ -267,11 +239,11 @@ case class BlockFetcherState(
     )
   }
 
-  def isExist(hash: ByteString): Boolean = isExistInReadyBlocks(hash) || isExistInWaitingHeaders(hash)
+  def exists(hash: ByteString): Boolean = existsInReadyBlocks(hash) || existsInWaitingHeaders(hash)
 
-  def isExistInWaitingHeaders(hash: ByteString): Boolean = waitingHeaders.exists(_.hash == hash)
+  def existsInWaitingHeaders(hash: ByteString): Boolean = waitingHeaders.exists(_.hash == hash)
 
-  def isExistInReadyBlocks(hash: ByteString): Boolean = readyBlocks.exists(_.hash == hash)
+  def existsInReadyBlocks(hash: ByteString): Boolean = readyBlocks.exists(_.hash == hash)
 
   def withLastBlock(nr: BigInt): BlockFetcherState = copy(lastBlock = nr)
 
@@ -296,14 +268,6 @@ case class BlockFetcherState(
   def withNewBodiesFetch: BlockFetcherState = copy(fetchingBodiesState = AwaitingBodies)
   def withBodiesFetchReceived: BlockFetcherState = copy(fetchingBodiesState = NotFetchingBodies)
 
-  def withPausedFetching: BlockFetcherState = copy(pausedFetching = true)
-  def withResumedFetching: BlockFetcherState = copy(pausedFetching = false)
-
-  def fetchingStateNode(hash: ByteString, requestor: ActorRef): BlockFetcherState =
-    copy(stateNodeFetcher = Some(StateNodeFetcher(hash, requestor)))
-
-  def notFetchingStateNode(): BlockFetcherState = copy(stateNodeFetcher = None)
-
   def status: Map[String, Any] = Map(
     "ready blocks" -> readyBlocks.size,
     "known top" -> knownTop,
@@ -314,7 +278,6 @@ case class BlockFetcherState(
     "fetched headers" -> waitingHeaders.size,
     "fetching headers" -> isFetchingHeaders,
     "fetching bodies" -> isFetchingBodies,
-    "fetching state node" -> isFetchingStateNode,
     "fetched top header" -> hasFetchedTopHeader,
     "first header" -> waitingHeaders.headOption.map(_.number),
     "first block" -> readyBlocks.headOption.map(_.number),
@@ -333,7 +296,6 @@ object BlockFetcherState {
       waitingHeaders = Queue(),
       fetchingHeadersState = NotFetchingHeaders,
       fetchingBodiesState = NotFetchingBodies,
-      stateNodeFetcher = None,
       lastBlock = lastBlock,
       knownTop = lastBlock + 1,
       blockProviders = Map()

src/main/scala/io/iohk/ethereum/blockchain/sync/regular/BlockFetcherState.scala

@@ -129,9 +129,9 @@ class BlockImporter(
 
   private def pickBlocks(state: ImporterState): Unit = {
     val msg =
-      state.resolvingBranchFrom.fold[BlockFetcher.FetchMsg](BlockFetcher.PickBlocks(syncConfig.blocksBatchSize))(from =>
-        BlockFetcher.StrictPickBlocks(from, startingBlockNumber)
-      )
+      state.resolvingBranchFrom.fold[BlockFetcher.FetchCommand](
+        BlockFetcher.PickBlocks(syncConfig.blocksBatchSize, self)
+      )(from => BlockFetcher.StrictPickBlocks(from, startingBlockNumber, self))
 
     fetcher ! msg
   }
@@ -172,7 +172,7 @@ class BlockImporter(
 
             err match {
               case e: MissingNodeException =>
-                fetcher ! BlockFetcher.FetchStateNode(e.hash)
+                fetcher ! BlockFetcher.FetchStateNode(e.hash, self)
                 ResolvingMissingNode(NonEmptyList(notImportedBlocks.head, notImportedBlocks.tail))
               case _ =>
                 val invalidBlockNr = notImportedBlocks.head.number
@@ -189,7 +189,7 @@ class BlockImporter(
     if (blocks.isEmpty) {
       importedBlocks.headOption match {
         case Some(block) =>
-          supervisor ! ProgressProtocol.ImportedBlock(block.number, block.hasCheckpoint, internally = false)
+          supervisor ! ProgressProtocol.ImportedBlock(block.number, internally = false)
         case None => ()
       }
 
@@ -243,7 +243,7 @@ class BlockImporter(
               val (blocks, weights) = importedBlocksData.map(data => (data.block, data.weight)).unzip
               broadcastBlocks(blocks, weights)
               updateTxPool(importedBlocksData.map(_.block), Seq.empty)
-              supervisor ! ProgressProtocol.ImportedBlock(block.number, block.hasCheckpoint, internally)
+              supervisor ! ProgressProtocol.ImportedBlock(block.number, internally)
             case BlockEnqueued => ()
             case DuplicateBlock => ()
             case UnknownParent => () // This is normal when receiving broadcast blocks
@@ -252,7 +252,7 @@ class BlockImporter(
               broadcastBlocks(newBranch, weights)
               newBranch.lastOption match {
                 case Some(newBlock) =>
-                  supervisor ! ProgressProtocol.ImportedBlock(newBlock.number, block.hasCheckpoint, internally)
+                  supervisor ! ProgressProtocol.ImportedBlock(newBlock.number, internally)
                 case None => ()
               }
             case BlockImportFailedDueToMissingNode(missingNodeException) if syncConfig.redownloadMissingStateNodes =>

src/main/scala/io/iohk/ethereum/blockchain/sync/regular/BlockImporter.scala

@@ -0,0 +1,72 @@
+package io.iohk.ethereum.blockchain.sync.regular
+
+import akka.actor.typed.{ActorRef, Behavior}
+import akka.actor.typed.scaladsl.{AbstractBehavior, ActorContext, Behaviors}
+import akka.actor.{ActorRef => ClassicActorRef}
+import akka.util.ByteString
+import io.iohk.ethereum.blockchain.sync.PeersClient.{BestPeer, Request}
+import io.iohk.ethereum.blockchain.sync.regular.BlockFetcher.FetchCommand
+import io.iohk.ethereum.blockchain.sync.regular.BodiesFetcher.BodiesFetcherCommand
+import io.iohk.ethereum.network.Peer
+import io.iohk.ethereum.network.p2p.Message
+import io.iohk.ethereum.network.p2p.messages.PV62.{BlockBodies, GetBlockBodies}
+import io.iohk.ethereum.utils.Config.SyncConfig
+import monix.execution.Scheduler
+
+import scala.util.{Failure, Success}
+
+class BodiesFetcher(
+    val peersClient: ClassicActorRef,
+    val syncConfig: SyncConfig,
+    val supervisor: ActorRef[FetchCommand],
+    context: ActorContext[BodiesFetcher.BodiesFetcherCommand]
+) extends AbstractBehavior[BodiesFetcher.BodiesFetcherCommand](context)
+    with FetchRequest[BodiesFetcherCommand] {
+
+  val log = context.log
+  implicit val ec: Scheduler = Scheduler(context.executionContext)
+
+  import BodiesFetcher._
+
+  override def makeAdaptedMessage[T <: Message](peer: Peer, msg: T): BodiesFetcherCommand = AdaptedMessage(peer, msg)
+
+  override def onMessage(message: BodiesFetcherCommand): Behavior[BodiesFetcherCommand] = {
+    message match {
+      case FetchBodies(hashes) =>
+        log.debug("Start fetching bodies")
+        requestBodies(hashes)
+        Behaviors.same
+      case AdaptedMessage(peer, BlockBodies(bodies)) =>
+        log.debug(s"Received ${bodies.size} block bodies")
+        supervisor ! BlockFetcher.ReceivedBodies(peer, bodies)
+        Behaviors.same
+      case BodiesFetcher.RetryBodiesRequest =>
+        supervisor ! BlockFetcher.RetryBodiesRequest
+        Behaviors.same
+      case _ => Behaviors.unhandled
+    }
+  }
+
+  private def requestBodies(hashes: Seq[ByteString]): Unit = {
+    val resp = makeRequest(Request.create(GetBlockBodies(hashes), BestPeer), BodiesFetcher.RetryBodiesRequest)
+    context.pipeToSelf(resp.runToFuture) {
+      case Success(res) => res
+      case Failure(_) => BodiesFetcher.RetryBodiesRequest
+    }
+  }
+}
+
+object BodiesFetcher {
+
+  def apply(
+      peersClient: ClassicActorRef,
+      syncConfig: SyncConfig,
+      supervisor: ActorRef[FetchCommand]
+  ): Behavior[BodiesFetcherCommand] =
+    Behaviors.setup(context => new BodiesFetcher(peersClient, syncConfig, supervisor, context))
+
+  sealed trait BodiesFetcherCommand
+  final case class FetchBodies(hashes: Seq[ByteString]) extends BodiesFetcherCommand
+  final case object RetryBodiesRequest extends BodiesFetcherCommand
+  private final case class AdaptedMessage[T <: Message](peer: Peer, msg: T) extends BodiesFetcherCommand
+}

src/main/scala/io/iohk/ethereum/blockchain/sync/regular/BodiesFetcher.scala

@@ -0,0 +1,56 @@
+package io.iohk.ethereum.blockchain.sync.regular
+
+import akka.actor.ActorRef
+import io.iohk.ethereum.blockchain.sync.PeersClient
+import io.iohk.ethereum.blockchain.sync.PeersClient.{BlacklistPeer, NoSuitablePeer, Request, RequestFailed}
+import io.iohk.ethereum.network.Peer
+import io.iohk.ethereum.network.p2p.Message
+import io.iohk.ethereum.utils.Config.SyncConfig
+import monix.eval.Task
+import org.slf4j.Logger
+import akka.pattern.ask
+import akka.util.Timeout
+import io.iohk.ethereum.utils.FunctorOps._
+
+import scala.concurrent.duration._
+import scala.util.Failure
+
+trait FetchRequest[A] {
+  val peersClient: ActorRef
+  val syncConfig: SyncConfig
+  val log: Logger
+
+  def makeAdaptedMessage[T <: Message](peer: Peer, msg: T): A
+
+  implicit val timeout: Timeout = syncConfig.peerResponseTimeout + 2.second // some margin for actor communication
+
+  def makeRequest(request: Request[_], responseFallback: A): Task[A] =
+    Task
+      .deferFuture(peersClient ? request)
+      .tap(blacklistPeerOnFailedRequest)
+      .flatMap(handleRequestResult(responseFallback))
+      .onErrorHandle { error =>
+        log.error("Unexpected error while doing a request", error)
+        responseFallback
+      }
+
+  def blacklistPeerOnFailedRequest(msg: Any): Unit = msg match {
+    case RequestFailed(peer, reason) => peersClient ! BlacklistPeer(peer.id, reason)
+    case _ => ()
+  }
+
+  def handleRequestResult(fallback: A)(msg: Any): Task[A] = {
+    msg match {
+      case failed: RequestFailed =>
+        log.debug("Request failed due to {}", failed)
+        Task.now(fallback)
+      case NoSuitablePeer =>
+        Task.now(fallback).delayExecution(syncConfig.syncRetryInterval)
+      case Failure(cause) =>
+        log.error("Unexpected error on the request result", cause)
+        Task.now(fallback)
+      case PeersClient.Response(peer, msg) =>
+        Task.now(makeAdaptedMessage(peer, msg))
+    }
+  }
+}

src/main/scala/io/iohk/ethereum/blockchain/sync/regular/FetchRequest.scala

@@ -0,0 +1,81 @@
+package io.iohk.ethereum.blockchain.sync.regular
+import akka.actor.typed.{ActorRef, Behavior}
+import akka.actor.typed.scaladsl.{AbstractBehavior, ActorContext, Behaviors}
+import akka.actor.{ActorRef => ClassicActorRef}
+import io.iohk.ethereum.blockchain.sync.PeersClient.{BestPeer, Request}
+import io.iohk.ethereum.blockchain.sync.regular.BlockFetcher.FetchCommand
+import io.iohk.ethereum.blockchain.sync.regular.HeadersFetcher.HeadersFetcherCommand
+import io.iohk.ethereum.network.Peer
+import io.iohk.ethereum.network.p2p.Message
+import io.iohk.ethereum.network.p2p.messages.PV62.{BlockHeaders, GetBlockHeaders}
+import io.iohk.ethereum.utils.Config.SyncConfig
+import monix.eval.Task
+import monix.execution.Scheduler
+import org.slf4j.Logger
+
+import scala.util.{Failure, Success}
+
+class HeadersFetcher(
+    val peersClient: ClassicActorRef,
+    val syncConfig: SyncConfig,
+    val supervisor: ActorRef[FetchCommand],
+    context: ActorContext[HeadersFetcher.HeadersFetcherCommand]
+) extends AbstractBehavior[HeadersFetcher.HeadersFetcherCommand](context)
+    with FetchRequest[HeadersFetcherCommand] {
+
+  override val log: Logger = context.log
+  implicit val ec: Scheduler = Scheduler(context.executionContext)
+
+  import HeadersFetcher._
+
+  override def makeAdaptedMessage[T <: Message](peer: Peer, msg: T): HeadersFetcherCommand = AdaptedMessage(peer, msg)
+
+  override def onMessage(message: HeadersFetcherCommand): Behavior[HeadersFetcherCommand] =
+    message match {
+      case FetchHeaders(blockNumber: BigInt, amount: BigInt) =>
+        log.debug("Start fetching headers from block {}", blockNumber)
+        requestHeaders(blockNumber, amount)
+        Behaviors.same
+      case AdaptedMessage(_, BlockHeaders(headers)) =>
+        log.debug("Fetched {} headers starting from block {}", headers.size, headers.headOption.map(_.number))
+        supervisor ! BlockFetcher.ReceivedHeaders(headers)
+        Behaviors.same
+      case HeadersFetcher.RetryHeadersRequest =>
+        supervisor ! BlockFetcher.RetryHeadersRequest
+        Behaviors.same
+      case _ => Behaviors.unhandled
+    }
+
+  private def requestHeaders(blockNr: BigInt, amount: BigInt): Unit = {
+    log.debug("Fetching headers from block {}", blockNr)
+    val msg = GetBlockHeaders(Left(blockNr), amount, skip = 0, reverse = false)
+
+    val resp = makeRequest(Request.create(msg, BestPeer), HeadersFetcher.RetryHeadersRequest)
+      .flatMap {
+        case AdaptedMessage(_, BlockHeaders(headers)) if headers.isEmpty =>
+          log.debug("Empty BlockHeaders response. Retry in {}", syncConfig.syncRetryInterval)
+          Task.now(HeadersFetcher.RetryHeadersRequest).delayResult(syncConfig.syncRetryInterval)
+        case res => Task.now(res)
+      }
+
+    context.pipeToSelf(resp.runToFuture) {
+      case Success(res) => res
+      case Failure(_) => HeadersFetcher.RetryHeadersRequest
+    }
+  }
+}
+
+object HeadersFetcher {
+
+  def apply(
+      peersClient: ClassicActorRef,
+      syncConfig: SyncConfig,
+      supervisor: ActorRef[FetchCommand]
+  ): Behavior[HeadersFetcherCommand] =
+    Behaviors.setup(context => new HeadersFetcher(peersClient, syncConfig, supervisor, context))
+
+  sealed trait HeadersFetcherCommand
+  final case class FetchHeaders(blockNumber: BigInt, amount: BigInt) extends HeadersFetcherCommand
+  final case object RetryHeadersRequest extends HeadersFetcherCommand
+  private final case class AdaptedMessage[T <: Message](peer: Peer, msg: T) extends HeadersFetcherCommand
+}