Java tutorial
/* * Copyright (c) 2015 Brocade Communications Systems, Inc. and others. All rights reserved. * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 which accompanies this distribution, * and is available at http://www.eclipse.org/legal/epl-v10.html */ package org.opendaylight.controller.cluster.raft; import akka.persistence.RecoveryCompleted; import akka.persistence.SnapshotOffer; import com.google.common.base.Stopwatch; import java.io.ByteArrayInputStream; import java.io.ObjectInputStream; import java.util.Collections; import org.opendaylight.controller.cluster.PersistentDataProvider; import org.opendaylight.controller.cluster.raft.base.messages.ApplySnapshot; import org.opendaylight.controller.cluster.raft.persisted.ApplyJournalEntries; import org.opendaylight.controller.cluster.raft.persisted.DeleteEntries; import org.opendaylight.controller.cluster.raft.persisted.MigratedSerializable; import org.opendaylight.controller.cluster.raft.persisted.ServerConfigurationPayload; import org.opendaylight.controller.cluster.raft.persisted.UpdateElectionTerm; import org.opendaylight.controller.cluster.raft.protobuff.client.messages.PersistentPayload; import org.slf4j.Logger; /** * Support class that handles persistence recovery for a RaftActor. * * @author Thomas Pantelis */ class RaftActorRecoverySupport { private final RaftActorContext context; private final RaftActorRecoveryCohort cohort; private int currentRecoveryBatchCount; private boolean dataRecoveredWithPersistenceDisabled; private boolean anyDataRecovered; private boolean hasMigratedDataRecovered; private Stopwatch recoveryTimer; private final Logger log; RaftActorRecoverySupport(final RaftActorContext context, final RaftActorRecoveryCohort cohort) { this.context = context; this.cohort = cohort; this.log = context.getLogger(); } boolean handleRecoveryMessage(Object message, PersistentDataProvider persistentProvider) { log.trace("{}: handleRecoveryMessage: {}", context.getId(), message); anyDataRecovered = anyDataRecovered || !(message instanceof RecoveryCompleted); if (isMigratedSerializable(message)) { hasMigratedDataRecovered = true; } boolean recoveryComplete = false; if (message instanceof UpdateElectionTerm) { context.getTermInformation().update(((UpdateElectionTerm) message).getCurrentTerm(), ((UpdateElectionTerm) message).getVotedFor()); } else if (message instanceof SnapshotOffer) { onRecoveredSnapshot((SnapshotOffer) message); } else if (message instanceof ReplicatedLogEntry) { onRecoveredJournalLogEntry((ReplicatedLogEntry) message); } else if (message instanceof ApplyJournalEntries) { onRecoveredApplyLogEntries(((ApplyJournalEntries) message).getToIndex()); } else if (message instanceof DeleteEntries) { onDeleteEntries((DeleteEntries) message); } else if (message instanceof RecoveryCompleted) { recoveryComplete = true; onRecoveryCompletedMessage(persistentProvider); } return recoveryComplete; } private void possiblyRestoreFromSnapshot() { byte[] restoreFromSnapshot = cohort.getRestoreFromSnapshot(); if (restoreFromSnapshot == null) { return; } if (anyDataRecovered) { log.warn("{}: The provided restore snapshot was not applied because the persistence store is not empty", context.getId()); return; } try (ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(restoreFromSnapshot))) { Snapshot snapshot = (Snapshot) ois.readObject(); log.debug("{}: Deserialized restore snapshot: {}", context.getId(), snapshot); context.getSnapshotManager().apply(new ApplySnapshot(snapshot)); } catch (Exception e) { log.error("{}: Error deserializing snapshot restore", context.getId(), e); } } private ReplicatedLog replicatedLog() { return context.getReplicatedLog(); } private void initRecoveryTimer() { if (recoveryTimer == null) { recoveryTimer = Stopwatch.createStarted(); } } private void onRecoveredSnapshot(SnapshotOffer offer) { if (log.isDebugEnabled()) { log.debug("{}: SnapshotOffer called..", context.getId()); } initRecoveryTimer(); Snapshot snapshot = (Snapshot) offer.snapshot(); for (ReplicatedLogEntry entry : snapshot.getUnAppliedEntries()) { if (isMigratedPayload(entry)) { hasMigratedDataRecovered = true; } } if (!context.getPersistenceProvider().isRecoveryApplicable()) { // We may have just transitioned to disabled and have a snapshot containing state data and/or log // entries - we don't want to preserve these, only the server config and election term info. snapshot = Snapshot.create(new byte[0], Collections.emptyList(), -1, -1, -1, -1, snapshot.getElectionTerm(), snapshot.getElectionVotedFor(), snapshot.getServerConfiguration()); } // Create a replicated log with the snapshot information // The replicated log can be used later on to retrieve this snapshot // when we need to install it on a peer context.setReplicatedLog(ReplicatedLogImpl.newInstance(snapshot, context)); context.setLastApplied(snapshot.getLastAppliedIndex()); context.setCommitIndex(snapshot.getLastAppliedIndex()); context.getTermInformation().update(snapshot.getElectionTerm(), snapshot.getElectionVotedFor()); Stopwatch timer = Stopwatch.createStarted(); // Apply the snapshot to the actors state cohort.applyRecoverySnapshot(snapshot.getState()); if (snapshot.getServerConfiguration() != null) { context.updatePeerIds(snapshot.getServerConfiguration()); if (isMigratedSerializable(snapshot.getServerConfiguration())) { hasMigratedDataRecovered = true; } } timer.stop(); log.info("Recovery snapshot applied for {} in {}: snapshotIndex={}, snapshotTerm={}, journal-size={}", context.getId(), timer.toString(), replicatedLog().getSnapshotIndex(), replicatedLog().getSnapshotTerm(), replicatedLog().size()); } private void onRecoveredJournalLogEntry(ReplicatedLogEntry logEntry) { if (log.isDebugEnabled()) { log.debug("{}: Received ReplicatedLogEntry for recovery: index: {}, size: {}", context.getId(), logEntry.getIndex(), logEntry.size()); } if (isServerConfigurationPayload(logEntry)) { context.updatePeerIds((ServerConfigurationPayload) logEntry.getData()); } if (isMigratedPayload(logEntry)) { hasMigratedDataRecovered = true; } if (context.getPersistenceProvider().isRecoveryApplicable()) { replicatedLog().append(logEntry); } else if (!isPersistentPayload(logEntry)) { dataRecoveredWithPersistenceDisabled = true; } } private void onRecoveredApplyLogEntries(long toIndex) { if (!context.getPersistenceProvider().isRecoveryApplicable()) { dataRecoveredWithPersistenceDisabled = true; return; } long lastUnappliedIndex = context.getLastApplied() + 1; if (log.isDebugEnabled()) { // it can happen that lastUnappliedIndex > toIndex, if the AJE is in the persistent journal // but the entry itself has made it to that state and recovered via the snapshot log.debug("{}: Received apply journal entries for recovery, applying to state: {} to {}", context.getId(), lastUnappliedIndex, toIndex); } long lastApplied = lastUnappliedIndex - 1; for (long i = lastUnappliedIndex; i <= toIndex; i++) { ReplicatedLogEntry logEntry = replicatedLog().get(i); if (logEntry != null) { lastApplied++; batchRecoveredLogEntry(logEntry); } else { // Shouldn't happen but cover it anyway. log.error("{}: Log entry not found for index {}", context.getId(), i); break; } } context.setLastApplied(lastApplied); context.setCommitIndex(lastApplied); } private void onDeleteEntries(DeleteEntries deleteEntries) { if (context.getPersistenceProvider().isRecoveryApplicable()) { replicatedLog().removeFrom(deleteEntries.getFromIndex()); } else { dataRecoveredWithPersistenceDisabled = true; } } private void batchRecoveredLogEntry(ReplicatedLogEntry logEntry) { initRecoveryTimer(); int batchSize = context.getConfigParams().getJournalRecoveryLogBatchSize(); if (!isServerConfigurationPayload(logEntry)) { if (currentRecoveryBatchCount == 0) { cohort.startLogRecoveryBatch(batchSize); } cohort.appendRecoveredLogEntry(logEntry.getData()); if (++currentRecoveryBatchCount >= batchSize) { endCurrentLogRecoveryBatch(); } } } private void endCurrentLogRecoveryBatch() { cohort.applyCurrentLogRecoveryBatch(); currentRecoveryBatchCount = 0; } private void onRecoveryCompletedMessage(PersistentDataProvider persistentProvider) { if (currentRecoveryBatchCount > 0) { endCurrentLogRecoveryBatch(); } String recoveryTime = ""; if (recoveryTimer != null) { recoveryTimer.stop(); recoveryTime = " in " + recoveryTimer.toString(); recoveryTimer = null; } log.info( "Recovery completed" + recoveryTime + " - Switching actor to Follower - " + "Persistence Id = " + context.getId() + " Last index in log = {}, snapshotIndex = {}, snapshotTerm = {}, " + "journal-size = {}", replicatedLog().lastIndex(), replicatedLog().getSnapshotIndex(), replicatedLog().getSnapshotTerm(), replicatedLog().size()); if (dataRecoveredWithPersistenceDisabled || (hasMigratedDataRecovered && !context.getPersistenceProvider().isRecoveryApplicable())) { if (hasMigratedDataRecovered) { log.info("{}: Saving snapshot after recovery due to migrated messages", context.getId()); } else { log.info("{}: Saving snapshot after recovery due to data persistence disabled", context.getId()); } // Either data persistence is disabled and we recovered some data entries (ie we must have just // transitioned to disabled or a persistence backup was restored) or we recovered migrated // messages. Either way, we persist a snapshot and delete all the messages from the akka journal // to clean out unwanted messages. Snapshot snapshot = Snapshot.create(new byte[0], Collections.<ReplicatedLogEntry>emptyList(), -1, -1, -1, -1, context.getTermInformation().getCurrentTerm(), context.getTermInformation().getVotedFor(), context.getPeerServerInfo(true)); persistentProvider.saveSnapshot(snapshot); persistentProvider.deleteMessages(persistentProvider.getLastSequenceNumber()); } else if (hasMigratedDataRecovered) { log.info("{}: Snapshot capture initiated after recovery due to migrated messages", context.getId()); context.getSnapshotManager().capture(replicatedLog().last(), -1); } else { possiblyRestoreFromSnapshot(); } } private static boolean isServerConfigurationPayload(ReplicatedLogEntry repLogEntry) { return repLogEntry.getData() instanceof ServerConfigurationPayload; } private static boolean isPersistentPayload(ReplicatedLogEntry repLogEntry) { return repLogEntry.getData() instanceof PersistentPayload; } private static boolean isMigratedPayload(ReplicatedLogEntry repLogEntry) { return isMigratedSerializable(repLogEntry.getData()); } private static boolean isMigratedSerializable(Object message) { return message instanceof MigratedSerializable && ((MigratedSerializable) message).isMigrated(); } }