[ETCM-77] checkpoint sync

src/main/scala/io/iohk/ethereum/blockchain/sync/SyncController.scala

@@ -2,6 +2,7 @@ package io.iohk.ethereum.blockchain.sync
 
 import akka.actor.{Actor, ActorLogging, ActorRef, PoisonPill, Props, Scheduler}
 import io.iohk.ethereum.blockchain.sync.regular.RegularSync
+import io.iohk.ethereum.consensus.blocks.CheckpointBlockGenerator
 import io.iohk.ethereum.consensus.validators.Validators
 import io.iohk.ethereum.db.storage.{AppStateStorage, FastSyncStateStorage}
 import io.iohk.ethereum.domain.Blockchain
@@ -16,6 +17,7 @@ class SyncController(
     validators: Validators,
     peerEventBus: ActorRef,
     pendingTransactionsManager: ActorRef,
+    checkpointBlockGenerator: CheckpointBlockGenerator,
     ommersPool: ActorRef,
     etcPeerManager: ActorRef,
     syncConfig: SyncConfig,
@@ -102,6 +104,7 @@ class SyncController(
         syncConfig,
         ommersPool,
         pendingTransactionsManager,
+        checkpointBlockGenerator,
         scheduler
       ),
       "regular-sync"
@@ -122,6 +125,7 @@ object SyncController {
       validators: Validators,
       peerEventBus: ActorRef,
       pendingTransactionsManager: ActorRef,
+      checkpointBlockGenerator: CheckpointBlockGenerator,
       ommersPool: ActorRef,
       etcPeerManager: ActorRef,
       syncConfig: SyncConfig
@@ -135,6 +139,7 @@ object SyncController {
         validators,
         peerEventBus,
         pendingTransactionsManager,
+        checkpointBlockGenerator,
         ommersPool,
         etcPeerManager,
         syncConfig

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

@@ -2,34 +2,40 @@ package io.iohk.ethereum.blockchain.sync.regular
 
 import akka.actor.Actor.Receive
 import akka.actor.{Actor, ActorLogging, ActorRef, NotInfluenceReceiveTimeout, Props, ReceiveTimeout}
+import akka.util.ByteString
 import cats.data.NonEmptyList
 import cats.instances.future._
 import cats.instances.list._
 import cats.syntax.apply._
 import io.iohk.ethereum.blockchain.sync.regular.BlockBroadcasterActor.BroadcastBlocks
-import io.iohk.ethereum.crypto.kec256
-import io.iohk.ethereum.domain.{Block, Blockchain, SignedTransaction}
+import io.iohk.ethereum.consensus.blocks.CheckpointBlockGenerator
+import io.iohk.ethereum.crypto.{ECDSASignature, kec256}
+import io.iohk.ethereum.domain.{Block, Blockchain, Checkpoint, SignedTransaction}
 import io.iohk.ethereum.ledger._
 import io.iohk.ethereum.mpt.MerklePatriciaTrie.MissingNodeException
 import io.iohk.ethereum.network.PeerId
 import io.iohk.ethereum.network.p2p.messages.CommonMessages.NewBlock
 import io.iohk.ethereum.ommers.OmmersPool.{AddOmmers, RemoveOmmers}
 import io.iohk.ethereum.transactions.PendingTransactionsManager
 import io.iohk.ethereum.transactions.PendingTransactionsManager.{AddUncheckedTransactions, RemoveTransactions}
+import io.iohk.ethereum.utils.ByteStringUtils
 import io.iohk.ethereum.utils.Config.SyncConfig
 import io.iohk.ethereum.utils.FunctorOps._
 
 import scala.concurrent.{ExecutionContext, Future}
+import scala.concurrent.duration._
 import scala.util.{Failure, Success}
 
+// scalastyle:off cyclomatic.complexity
 class BlockImporter(
     fetcher: ActorRef,
     ledger: Ledger,
     blockchain: Blockchain,
     syncConfig: SyncConfig,
     ommersPool: ActorRef,
     broadcaster: ActorRef,
-    pendingTransactionsManager: ActorRef
+    pendingTransactionsManager: ActorRef,
+    checkpointBlockGenerator: CheckpointBlockGenerator
 ) extends Actor
     with ActorLogging {
   import BlockImporter._
@@ -56,15 +62,35 @@ class BlockImporter(
 
   private def running(state: ImporterState): Receive = handleTopMessages(state, running) orElse {
     case ReceiveTimeout => self ! PickBlocks
+
     case PrintStatus => log.info("Block: {}, is on top?: {}", blockchain.getBestBlockNumber(), state.isOnTop)
+
     case BlockFetcher.PickedBlocks(blocks) =>
       SignedTransaction.retrieveSendersInBackGround(blocks.toList.map(_.body))
       importBlocks(blocks)(state)
+
     case MinedBlock(block) =>
       if (!state.importing) {
         importMinedBlock(block, state)
       }
+
+    case nc @ NewCheckpoint(parentHash, signatures) =>
+      if (state.importing) {
+        //We don't want to lose a checkpoint
+        context.system.scheduler.scheduleOnce(1.second, self, nc)
+      } else {
+        ledger.getBlockByHash(parentHash) match {
+          case Some(parent) =>
+            val checkpointBlock = checkpointBlockGenerator.generate(parent, Checkpoint(signatures))
+            importCheckpointBlock(checkpointBlock, state)
+
+          case None =>
+            log.error(s"Could not find parent (${ByteStringUtils.hash2string(parentHash)}) for new checkpoint block")
+        }
+      }
+
     case ImportNewBlock(block, peerId) if state.isOnTop && !state.importing => importNewBlock(block, peerId, state)
+
     case ImportDone(newBehavior) =>
       val newState = state.notImportingBlocks().branchResolved()
       val behavior: Behavior = getBehavior(newBehavior)
@@ -177,6 +203,9 @@ class BlockImporter(
   private def importMinedBlock(block: Block, state: ImporterState): Unit =
     importBlock(block, new MinedBlockImportMessages(block), informFetcherOnFail = false)(state)
 
+  private def importCheckpointBlock(block: Block, state: ImporterState): Unit =
+    importBlock(block, new CheckpointBlockImportMessages(block), informFetcherOnFail = false)(state)
+
   private def importNewBlock(block: Block, peerId: PeerId, state: ImporterState): Unit =
     importBlock(block, new NewBlockImportMessages(block, peerId), informFetcherOnFail = true)(state)
 
@@ -247,7 +276,7 @@ class BlockImporter(
 
   // Either block from which we try resolve branch or list of blocks to be imported
   private def resolveBranch(blocks: NonEmptyList[Block]): Either[BigInt, List[Block]] =
-    ledger.resolveBranch(blocks.map(_.header).toList) match {
+    ledger.resolveBranch(blocks.map(_.header)) match {
       case NewBetterBranch(oldBranch) =>
         val transactionsToAdd = oldBranch.flatMap(_.body.transactionList)
         pendingTransactionsManager ! PendingTransactionsManager.AddUncheckedTransactions(transactionsToAdd)
@@ -294,10 +323,20 @@ object BlockImporter {
       syncConfig: SyncConfig,
       ommersPool: ActorRef,
       broadcaster: ActorRef,
-      pendingTransactionsManager: ActorRef
+      pendingTransactionsManager: ActorRef,
+      checkpointBlockGenerator: CheckpointBlockGenerator
   ): Props =
     Props(
-      new BlockImporter(fetcher, ledger, blockchain, syncConfig, ommersPool, broadcaster, pendingTransactionsManager)
+      new BlockImporter(
+        fetcher,
+        ledger,
+        blockchain,
+        syncConfig,
+        ommersPool,
+        broadcaster,
+        pendingTransactionsManager,
+        checkpointBlockGenerator
+      )
     )
 
   type Behavior = ImporterState => Receive
@@ -308,6 +347,7 @@ object BlockImporter {
   case object OnTop extends ImporterMsg
   case object NotOnTop extends ImporterMsg
   case class MinedBlock(block: Block) extends ImporterMsg
+  case class NewCheckpoint(parentHash: ByteString, signatures: Seq[ECDSASignature]) extends ImporterMsg
   case class ImportNewBlock(block: Block, peerId: PeerId) extends ImporterMsg
   case class ImportDone(newBehavior: NewBehavior) extends ImporterMsg
   case object PickBlocks extends ImporterMsg

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

@@ -54,6 +54,24 @@ class MinedBlockImportMessages(block: Block) extends ImportMessages(block) {
     (ErrorLevel, s"Ignoring mined block $exception")
 }
 
+class CheckpointBlockImportMessages(block: Block) extends ImportMessages(block) {
+  import ImportMessages._
+  override def preImport(): LogEntry = (DebugLevel, s"Importing new checkpoint block (${block.idTag})")
+  override def importedToTheTop(): LogEntry =
+    (DebugLevel, s"Added new checkpoint block $number to top of the chain")
+  override def enqueued(): LogEntry = (DebugLevel, s"Checkpoint block $number was added to the queue")
+  override def duplicated(): LogEntry =
+    (DebugLevel, "Ignoring duplicate checkpoint block")
+  override def orphaned(): LogEntry =
+    (ErrorLevel, "Checkpoint block has no parent. This should never happen")
+  override def reorganisedChain(newBranch: List[Block]): LogEntry =
+    (DebugLevel, s"Addition of new checkpoint block $number resulting in chain reorganization")
+  override def importFailed(error: String): LogEntry =
+    (WarningLevel, s"Failed to execute checkpoint block because of $error")
+  override def missingStateNode(exception: MissingNodeException): LogEntry =
+    (ErrorLevel, s"Ignoring checkpoint block: $exception")
+}
+
 class NewBlockImportMessages(block: Block, peerId: PeerId) extends ImportMessages(block) {
   import ImportMessages._
   override def preImport(): LogEntry = (DebugLevel, s"Handling NewBlock message for block (${block.idTag})")

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

@@ -3,9 +3,11 @@ package io.iohk.ethereum.blockchain.sync.regular
 import akka.actor.{Actor, ActorLogging, ActorRef, AllForOneStrategy, Cancellable, Props, Scheduler, SupervisorStrategy}
 import akka.util.ByteString
 import io.iohk.ethereum.blockchain.sync.BlockBroadcast
+import io.iohk.ethereum.consensus.blocks.CheckpointBlockGenerator
 import io.iohk.ethereum.crypto.ECDSASignature
 import io.iohk.ethereum.domain.{Block, Blockchain}
 import io.iohk.ethereum.ledger.Ledger
+import io.iohk.ethereum.utils.ByteStringUtils
 import io.iohk.ethereum.utils.Config.SyncConfig
 
 class RegularSync(
@@ -17,6 +19,7 @@ class RegularSync(
     syncConfig: SyncConfig,
     ommersPool: ActorRef,
     pendingTransactionsManager: ActorRef,
+    checkpointBlockGenerator: CheckpointBlockGenerator,
     scheduler: Scheduler
 ) extends Actor
     with ActorLogging {
@@ -31,7 +34,16 @@ class RegularSync(
   )
   val importer: ActorRef =
     context.actorOf(
-      BlockImporter.props(fetcher, ledger, blockchain, syncConfig, ommersPool, broadcaster, pendingTransactionsManager),
+      BlockImporter.props(
+        fetcher,
+        ledger,
+        blockchain,
+        syncConfig,
+        ommersPool,
+        broadcaster,
+        pendingTransactionsManager,
+        checkpointBlockGenerator
+      ),
       "block-importer"
     )
 
@@ -57,6 +69,10 @@ class RegularSync(
     case MinedBlock(block) =>
       log.info(s"Block mined [number = {}, hash = {}]", block.number, block.header.hashAsHexString)
       importer ! BlockImporter.MinedBlock(block)
+
+    case NewCheckpoint(parentHash, signatures) =>
+      log.info(s"Received new checkpoint for block ${ByteStringUtils.hash2string(parentHash)}")
+      importer ! BlockImporter.NewCheckpoint(parentHash, signatures)
   }
 
   override def supervisorStrategy: SupervisorStrategy = AllForOneStrategy()(SupervisorStrategy.defaultDecider)
@@ -78,6 +94,7 @@ object RegularSync {
       syncConfig: SyncConfig,
       ommersPool: ActorRef,
       pendingTransactionsManager: ActorRef,
+      checkpointBlockGenerator: CheckpointBlockGenerator,
       scheduler: Scheduler
   ): Props =
     Props(
@@ -90,6 +107,7 @@ object RegularSync {
         syncConfig,
         ommersPool,
         pendingTransactionsManager,
+        checkpointBlockGenerator,
         scheduler
       )
     )

src/main/scala/io/iohk/ethereum/consensus/Consensus.scala

@@ -1,11 +1,13 @@
 package io.iohk.ethereum.consensus
 
 import io.iohk.ethereum.consensus.blocks.{BlockGenerator, TestBlockGenerator}
+import io.iohk.ethereum.consensus.difficulty.DifficultyCalculator
 import io.iohk.ethereum.consensus.ethash.{MinerProtocol, MinerResponse}
 import io.iohk.ethereum.consensus.validators.Validators
 import io.iohk.ethereum.ledger.BlockPreparator
 import io.iohk.ethereum.ledger.Ledger.VMImpl
 import io.iohk.ethereum.nodebuilder.Node
+
 import scala.concurrent.Future
 
 /**
@@ -46,6 +48,8 @@ trait Consensus {
     */
   def blockGenerator: BlockGenerator
 
+  def difficultyCalculator: DifficultyCalculator
+
   /**
     * Starts the consensus protocol on the current `node`.
     */

src/main/scala/io/iohk/ethereum/consensus/blocks/BlockGeneratorSkeleton.scala

@@ -21,16 +21,12 @@ import io.iohk.ethereum.utils.ByteUtils.or
 
 /**
   * This is a skeleton for a generic [[io.iohk.ethereum.consensus.blocks.BlockGenerator BlockGenerator]].
-  *
-  * @param blockchain
-  * @param blockchainConfig
-  * @param _blockTimestampProvider
   */
 abstract class BlockGeneratorSkeleton(
     blockchain: Blockchain,
     blockchainConfig: BlockchainConfig,
     consensusConfig: ConsensusConfig,
-    blockPreparator: BlockPreparator,
+    difficultyCalc: DifficultyCalculator,
     _blockTimestampProvider: BlockTimestampProvider = DefaultBlockTimestampProvider
 ) extends TestBlockGenerator {
 
@@ -42,8 +38,6 @@ abstract class BlockGeneratorSkeleton(
 
   protected def newBlockBody(transactions: Seq[SignedTransaction], x: X): BlockBody
 
-  protected def difficulty: DifficultyCalculator
-
   protected def defaultPrepareHeader(
       blockNumber: BigInt,
       parent: Block,
@@ -66,7 +60,7 @@ abstract class BlockGeneratorSkeleton(
       transactionsRoot = ByteString.empty,
       receiptsRoot = ByteString.empty,
       logsBloom = ByteString.empty,
-      difficulty = difficulty.calculateDifficulty(blockNumber, blockTimestamp, parent.header),
+      difficulty = difficultyCalc.calculateDifficulty(blockNumber, blockTimestamp, parent.header),
       number = blockNumber,
       gasLimit = calculateGasLimit(parent.header.gasLimit),
       gasUsed = 0,

src/main/scala/io/iohk/ethereum/consensus/blocks/CheckpointBlockGenerator.scala

@@ -0,0 +1,37 @@
+package io.iohk.ethereum.consensus.blocks
+
+import akka.util.ByteString
+import io.iohk.ethereum.domain.BlockHeader.HeaderExtraFields.HefPostEcip1097
+import io.iohk.ethereum.domain._
+import io.iohk.ethereum.ledger.BloomFilter
+
+class CheckpointBlockGenerator {
+
+  def generate(parent: Block, checkpoint: Checkpoint): Block = {
+    val blockNumber = parent.number + 1
+    // we are using a predictable value for timestamp so that each federation node generates identical block
+    // see ETCM-173
+    val timestamp = parent.header.unixTimestamp + 1
+
+    val header = BlockHeader(
+      parentHash = parent.hash,
+      ommersHash = BlockHeader.EmptyOmmers,
+      beneficiary = BlockHeader.EmptyBeneficiary,
+      difficulty = parent.header.difficulty,
+      number = blockNumber,
+      gasLimit = parent.header.gasLimit,
+      unixTimestamp = timestamp,
+      extraData = ByteString.empty,
+      stateRoot = parent.header.stateRoot,
+      transactionsRoot = BlockHeader.EmptyMpt,
+      receiptsRoot = BlockHeader.EmptyMpt,
+      logsBloom = BloomFilter.EmptyBloomFilter,
+      gasUsed = UInt256.Zero,
+      mixHash = ByteString.empty,
+      nonce = ByteString.empty,
+      extraFields = HefPostEcip1097(false, Some(checkpoint))
+    )
+
+    Block(header, BlockBody.empty)
+  }
+}

src/main/scala/io/iohk/ethereum/consensus/blocks/NoOmmersBlockGenerator.scala

@@ -1,6 +1,7 @@
 package io.iohk.ethereum.consensus.blocks
 
 import io.iohk.ethereum.consensus.ConsensusConfig
+import io.iohk.ethereum.consensus.difficulty.DifficultyCalculator
 import io.iohk.ethereum.domain._
 import io.iohk.ethereum.ledger.{BlockPreparationError, BlockPreparator}
 import io.iohk.ethereum.utils.BlockchainConfig
@@ -10,12 +11,13 @@ abstract class NoOmmersBlockGenerator(
     blockchainConfig: BlockchainConfig,
     consensusConfig: ConsensusConfig,
     blockPreparator: BlockPreparator,
+    difficultyCalc: DifficultyCalculator,
     blockTimestampProvider: BlockTimestampProvider = DefaultBlockTimestampProvider
 ) extends BlockGeneratorSkeleton(
       blockchain,
       blockchainConfig,
       consensusConfig,
-      blockPreparator,
+      difficultyCalc,
       blockTimestampProvider
     ) {