[NC-1273] Start of fast sync downloader (#613)

* Add support for initiating fast sync to DefaultSynchronizer, starting full sync once that completes. * Wait for a minimum number of peers to be available before starting fast sync. * Select pivot block. * Fetch the pivot block header. * Ensure that a majority of peers (which have the pivot block) agree on the block. * Pull isRetryingError and assignPeer up to AbstractRetryingPeerTask so it can be reused.
PegaSysEng · Jan 23, 2019 · aa58d67 · aa58d67
1 parent c8f1748
commit aa58d67
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Showing 25 changed files with 1,145 additions and 128 deletions.
diff --git a/...th/src/main/java/tech/pegasys/pantheon/ethereum/eth/manager/AbstractRetryingPeerTask.java b/...th/src/main/java/tech/pegasys/pantheon/ethereum/eth/manager/AbstractRetryingPeerTask.java
@@ -14,22 +14,26 @@
 
 import tech.pegasys.pantheon.ethereum.eth.manager.exceptions.MaxRetriesReachedException;
 import tech.pegasys.pantheon.ethereum.eth.manager.exceptions.NoAvailablePeersException;
+import tech.pegasys.pantheon.ethereum.eth.manager.exceptions.PeerBreachedProtocolException;
+import tech.pegasys.pantheon.ethereum.eth.manager.exceptions.PeerDisconnectedException;
 import tech.pegasys.pantheon.ethereum.eth.sync.tasks.WaitForPeerTask;
 import tech.pegasys.pantheon.metrics.LabelledMetric;
 import tech.pegasys.pantheon.metrics.OperationTimer;
 import tech.pegasys.pantheon.util.ExceptionUtils;
 
 import java.time.Duration;
 import java.util.Collection;
+import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeoutException;
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
 /**
  * A task that will retry a fixed number of times before completing the associated CompletableFuture
  * exceptionally with a new {@link MaxRetriesReachedException}. If the future returned from {@link
- * #executePeerTask()} is complete with a non-empty list the retry counter is reset.
+ * #executePeerTask(Optional)} is complete with a non-empty list the retry counter is reset.
  *
  * @param <T> The type as a typed list that the peer task can get partial or full results in.
  */
@@ -40,6 +44,7 @@ public abstract class AbstractRetryingPeerTask<T extends Collection<?>> extends
   private final int maxRetries;
   private int retryCount = 0;
   private final LabelledMetric<OperationTimer> ethTasksTimer;
+  private Optional<EthPeer> assignedPeer = Optional.empty();
 
   /**
    * @param ethContext The context of the current Eth network we are attached to.
@@ -56,6 +61,10 @@ public AbstractRetryingPeerTask(
     this.maxRetries = maxRetries;
   }
 
+  public void assignPeer(final EthPeer peer) {
+    assignedPeer = Optional.of(peer);
+  }
+
   @Override
   protected void executeTask() {
     if (result.get().isDone()) {
@@ -68,7 +77,7 @@ protected void executeTask() {
     }
 
     retryCount += 1;
-    executePeerTask()
+    executePeerTask(assignedPeer)
         .whenComplete(
             (peerResult, error) -> {
               if (error != null) {
@@ -83,7 +92,7 @@ protected void executeTask() {
             });
   }
 
-  protected abstract CompletableFuture<T> executePeerTask();
+  protected abstract CompletableFuture<T> executePeerTask(Optional<EthPeer> assignedPeer);
 
   private void handleTaskError(final Throwable error) {
     final Throwable cause = ExceptionUtils.rootCause(error);
@@ -118,5 +127,12 @@ private void handleTaskError(final Throwable error) {
                 .scheduleFutureTask(this::executeTaskTimed, Duration.ofSeconds(1)));
   }
 
-  protected abstract boolean isRetryableError(Throwable error);
+  private boolean isRetryableError(final Throwable error) {
+    final boolean isPeerError =
+        error instanceof PeerBreachedProtocolException
+            || error instanceof PeerDisconnectedException
+            || error instanceof NoAvailablePeersException;
+
+    return error instanceof TimeoutException || (!assignedPeer.isPresent() && isPeerError);
+  }
 }
diff --git a/ethereum/eth/src/main/java/tech/pegasys/pantheon/ethereum/eth/sync/DefaultSynchronizer.java b/ethereum/eth/src/main/java/tech/pegasys/pantheon/ethereum/eth/sync/DefaultSynchronizer.java
@@ -16,11 +16,16 @@
 import tech.pegasys.pantheon.ethereum.core.SyncStatus;
 import tech.pegasys.pantheon.ethereum.core.Synchronizer;
 import tech.pegasys.pantheon.ethereum.eth.manager.EthContext;
+import tech.pegasys.pantheon.ethereum.eth.sync.fastsync.FastSyncActions;
+import tech.pegasys.pantheon.ethereum.eth.sync.fastsync.FastSyncDownloader;
+import tech.pegasys.pantheon.ethereum.eth.sync.fastsync.FastSyncException;
+import tech.pegasys.pantheon.ethereum.eth.sync.fastsync.FastSyncState;
 import tech.pegasys.pantheon.ethereum.eth.sync.state.PendingBlocks;
 import tech.pegasys.pantheon.ethereum.eth.sync.state.SyncState;
 import tech.pegasys.pantheon.ethereum.mainnet.ProtocolSchedule;
 import tech.pegasys.pantheon.metrics.LabelledMetric;
 import tech.pegasys.pantheon.metrics.OperationTimer;
+import tech.pegasys.pantheon.util.ExceptionUtils;
 
 import java.util.Optional;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -35,7 +40,8 @@ public class DefaultSynchronizer<C> implements Synchronizer {
   private final SyncState syncState;
   private final AtomicBoolean started = new AtomicBoolean(false);
   private final BlockPropagationManager<C> blockPropagationManager;
-  private final Downloader<C> downloader;
+  private final FullSyncDownloader<C> fullSyncDownloader;
+  private final Optional<FastSyncDownloader<C>> fastSyncDownloader;
 
   public DefaultSynchronizer(
       final SynchronizerConfiguration syncConfig,
@@ -54,28 +60,60 @@ public DefaultSynchronizer(
             syncState,
             new PendingBlocks(),
             ethTasksTimer);
-    this.downloader =
-        new Downloader<>(
+    this.fullSyncDownloader =
+        new FullSyncDownloader<>(
             syncConfig, protocolSchedule, protocolContext, ethContext, syncState, ethTasksTimer);
 
     ChainHeadTracker.trackChainHeadForPeers(
         ethContext, protocolSchedule, protocolContext.getBlockchain(), syncConfig, ethTasksTimer);
-    if (syncConfig.syncMode().equals(SyncMode.FAST)) {
+    if (syncConfig.syncMode() == SyncMode.FAST) {
       LOG.info("Fast sync enabled.");
+      this.fastSyncDownloader =
+          Optional.of(
+              new FastSyncDownloader<>(
+                  new FastSyncActions<>(
+                      syncConfig, protocolSchedule, protocolContext, ethContext, ethTasksTimer)));
+    } else {
+      this.fastSyncDownloader = Optional.empty();
     }
   }
 
   @Override
   public void start() {
     if (started.compareAndSet(false, true)) {
-      LOG.info("Starting synchronizer.");
-      blockPropagationManager.start();
-      downloader.start();
+      if (fastSyncDownloader.isPresent()) {
+        fastSyncDownloader.get().start().whenComplete(this::handleFastSyncResult);
+      } else {
+        startFullSync();
+      }
     } else {
       throw new IllegalStateException("Attempt to start an already started synchronizer.");
     }
   }
 
+  private void handleFastSyncResult(final FastSyncState result, final Throwable error) {
+
+    final Throwable rootCause = ExceptionUtils.rootCause(error);
+    if (rootCause instanceof FastSyncException) {
+      LOG.error(
+          "Fast sync failed ({}), switching to full sync.",
+          ((FastSyncException) rootCause).getError());
+    } else if (error != null) {
+      LOG.error("Fast sync failed, switching to full sync.", error);
+    } else {
+      LOG.info(
+          "Fast sync completed successfully with pivot block {}",
+          result.getPivotBlockNumber().getAsLong());
+    }
+    startFullSync();
+  }
+
+  private void startFullSync() {
+    LOG.info("Starting synchronizer.");
+    blockPropagationManager.start();
+    fullSyncDownloader.start();
+  }
+
   @Override
   public Optional<SyncStatus> getSyncStatus() {
     if (!started.get()) {

diff --git a/...antheon/ethereum/eth/sync/Downloader.java → ...ethereum/eth/sync/FullSyncDownloader.java b/...antheon/ethereum/eth/sync/Downloader.java → ...ethereum/eth/sync/FullSyncDownloader.java
@@ -54,7 +54,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-public class Downloader<C> {
+public class FullSyncDownloader<C> {
   private static final Logger LOG = LogManager.getLogger();
 
   private final SynchronizerConfiguration config;
@@ -73,7 +73,7 @@ public class Downloader<C> {
   private long syncTargetDisconnectListenerId;
   protected CompletableFuture<?> currentTask;
 
-  Downloader(
+  FullSyncDownloader(
       final SynchronizerConfiguration config,
       final ProtocolSchedule<C> protocolSchedule,
       final ProtocolContext<C> protocolContext,

diff --git a/.../eth/src/main/java/tech/pegasys/pantheon/ethereum/eth/sync/SynchronizerConfiguration.java b/.../eth/src/main/java/tech/pegasys/pantheon/ethereum/eth/sync/SynchronizerConfiguration.java
@@ -18,6 +18,7 @@
 import tech.pegasys.pantheon.ethereum.core.BlockHeader;
 import tech.pegasys.pantheon.util.uint.UInt256;
 
+import java.time.Duration;
 import java.util.Optional;
 
 import com.google.common.collect.Range;
@@ -30,10 +31,14 @@ public class SynchronizerConfiguration {
   // TODO: Determine reasonable defaults here
   public static int DEFAULT_PIVOT_DISTANCE_FROM_HEAD = 500;
   public static float DEFAULT_FULL_VALIDATION_RATE = .1f;
+  public static int DEFAULT_FAST_SYNC_MINIMUM_PEERS = 5;
+  private static final Duration DEFAULT_FAST_SYNC_MAXIMUM_PEER_WAIT_TIME = Duration.ofSeconds(3);
 
   // Fast sync config
   private final int fastSyncPivotDistance;
   private final float fastSyncFullValidationRate;
+  private final int fastSyncMinimumPeerCount;
+  private final Duration fastSyncMaximumPeerWaitTime;
 
   // Block propagation config
   private final Range<Long> blockPropagationRange;
@@ -58,6 +63,8 @@ private SynchronizerConfiguration(
       final SyncMode requestedSyncMode,
       final int fastSyncPivotDistance,
       final float fastSyncFullValidationRate,
+      final int fastSyncMinimumPeerCount,
+      final Duration fastSyncMaximumPeerWaitTime,
       final Range<Long> blockPropagationRange,
       final Optional<SyncMode> syncMode,
       final long downloaderChangeTargetThresholdByHeight,
@@ -73,6 +80,8 @@ private SynchronizerConfiguration(
     this.requestedSyncMode = requestedSyncMode;
     this.fastSyncPivotDistance = fastSyncPivotDistance;
     this.fastSyncFullValidationRate = fastSyncFullValidationRate;
+    this.fastSyncMinimumPeerCount = fastSyncMinimumPeerCount;
+    this.fastSyncMaximumPeerWaitTime = fastSyncMaximumPeerWaitTime;
     this.blockPropagationRange = blockPropagationRange;
     this.syncMode = syncMode;
     this.downloaderChangeTargetThresholdByHeight = downloaderChangeTargetThresholdByHeight;
@@ -115,6 +124,8 @@ public SynchronizerConfiguration validated(final Blockchain blockchain) {
         requestedSyncMode,
         fastSyncPivotDistance,
         fastSyncFullValidationRate,
+        fastSyncMinimumPeerCount,
+        fastSyncMaximumPeerWaitTime,
         blockPropagationRange,
         Optional.of(actualSyncMode),
         downloaderChangeTargetThresholdByHeight,
@@ -222,6 +233,14 @@ public float fastSyncFullValidationRate() {
     return fastSyncFullValidationRate;
   }
 
+  public int getFastSyncMinimumPeerCount() {
+    return fastSyncMinimumPeerCount;
+  }
+
+  public Duration getFastSyncMaximumPeerWaitTime() {
+    return fastSyncMaximumPeerWaitTime;
+  }
+
   public static class Builder {
     private int fastSyncPivotDistance = DEFAULT_PIVOT_DISTANCE_FROM_HEAD;
     private float fastSyncFullValidationRate = DEFAULT_FULL_VALIDATION_RATE;
@@ -318,6 +337,8 @@ public SynchronizerConfiguration build() {
           syncMode,
           fastSyncPivotDistance,
           fastSyncFullValidationRate,
+          DEFAULT_FAST_SYNC_MINIMUM_PEERS,
+          DEFAULT_FAST_SYNC_MAXIMUM_PEER_WAIT_TIME,
           blockPropagationRange,
           Optional.empty(),
           downloaderChangeTargetThresholdByHeight,