+ private boolean processNewEntries(final AppendEntries appendEntries, final ActorRef sender) {
+ int numLogEntries = appendEntries.getEntries().size();
+ if (numLogEntries == 0) {
+ return true;
+ }
+
+ log.debug("{}: Number of entries to be appended = {}", logName(), numLogEntries);
+
+ long lastIndex = lastIndex();
+ int addEntriesFrom = 0;
+
+ // First check for conflicting entries. If an existing entry conflicts with a new one (same index but different
+ // term), delete the existing entry and all that follow it (§5.3)
+ if (context.getReplicatedLog().size() > 0) {
+ // Find the entry up until the one that is not in the follower's log
+ for (int i = 0;i < numLogEntries; i++, addEntriesFrom++) {
+ ReplicatedLogEntry matchEntry = appendEntries.getEntries().get(i);
+
+ if (!isLogEntryPresent(matchEntry.getIndex())) {
+ // newEntry not found in the log
+ break;
+ }
+
+ long existingEntryTerm = getLogEntryTerm(matchEntry.getIndex());
+
+ log.debug("{}: matchEntry {} is present: existingEntryTerm: {}", logName(), matchEntry,
+ existingEntryTerm);
+
+ // existingEntryTerm == -1 means it's in the snapshot and not in the log. We don't know
+ // what the term was so we'll assume it matches.
+ if (existingEntryTerm == -1 || existingEntryTerm == matchEntry.getTerm()) {
+ continue;
+ }
+
+ if (!context.getRaftPolicy().applyModificationToStateBeforeConsensus()) {
+ log.info("{}: Removing entries from log starting at {}", logName(), matchEntry.getIndex());
+
+ // Entries do not match so remove all subsequent entries
+ if (!context.getReplicatedLog().removeFromAndPersist(matchEntry.getIndex())) {
+ // Could not remove the entries - this means the matchEntry index must be in the
+ // snapshot and not the log. In this case the prior entries are part of the state
+ // so we must send back a reply to force a snapshot to completely re-sync the
+ // follower's log and state.
+
+ log.info("{}: Could not remove entries - sending reply to force snapshot", logName());
+ sender.tell(new AppendEntriesReply(context.getId(), currentTerm(), false, lastIndex,
+ lastTerm(), context.getPayloadVersion(), true), actor());
+ return false;
+ }
+
+ break;
+ } else {
+ sender.tell(new AppendEntriesReply(context.getId(), currentTerm(), false, lastIndex,
+ lastTerm(), context.getPayloadVersion(), true), actor());
+ return false;
+ }
+ }
+ }
+
+ lastIndex = lastIndex();
+ log.debug("{}: After cleanup, lastIndex: {}, entries to be added from: {}", logName(), lastIndex,
+ addEntriesFrom);
+
+ // When persistence successfully completes for each new log entry appended, we need to determine if we
+ // should capture a snapshot to compact the persisted log. shouldCaptureSnapshot tracks whether or not
+ // one of the log entries has exceeded the log size threshold whereby a snapshot should be taken. However
+ // we don't initiate the snapshot at that log entry but rather after the last log entry has been persisted.
+ // This is done because subsequent log entries after the one that tripped the threshold may have been
+ // applied to the state already, as the persistence callback occurs async, and we want those entries
+ // purged from the persisted log as well.
+ final AtomicBoolean shouldCaptureSnapshot = new AtomicBoolean(false);
+ final Procedure<ReplicatedLogEntry> appendAndPersistCallback = logEntry -> {
+ final List<ReplicatedLogEntry> entries = appendEntries.getEntries();
+ final ReplicatedLogEntry lastEntryToAppend = entries.get(entries.size() - 1);
+ if (shouldCaptureSnapshot.get() && logEntry == lastEntryToAppend) {
+ context.getSnapshotManager().capture(context.getReplicatedLog().last(), getReplicatedToAllIndex());
+ }
+ };
+
+ // Append any new entries not already in the log
+ for (int i = addEntriesFrom; i < numLogEntries; i++) {
+ ReplicatedLogEntry entry = appendEntries.getEntries().get(i);
+
+ log.debug("{}: Append entry to log {}", logName(), entry.getData());
+
+ context.getReplicatedLog().appendAndPersist(entry, appendAndPersistCallback, false);
+
+ shouldCaptureSnapshot.compareAndSet(false,
+ context.getReplicatedLog().shouldCaptureSnapshot(entry.getIndex()));
+
+ if (entry.getData() instanceof ServerConfigurationPayload) {
+ context.updatePeerIds((ServerConfigurationPayload)entry.getData());
+ }
+ }
+
+ log.debug("{}: Log size is now {}", logName(), context.getReplicatedLog().size());
+
+ return true;
+ }
+
+ private boolean isOutOfSync(final AppendEntries appendEntries, final ActorRef sender) {
Code Review / controller.git / commitdiff