package org.opendaylight.controller.cluster.raft.behaviors;
import akka.actor.ActorRef;
+import akka.japi.Procedure;
import com.google.common.annotations.VisibleForTesting;
import java.util.ArrayList;
+import javax.annotation.Nullable;
import org.opendaylight.controller.cluster.raft.RaftActorContext;
import org.opendaylight.controller.cluster.raft.RaftState;
import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
* </ul>
*/
public class Follower extends AbstractRaftActorBehavior {
-
- private SnapshotTracker snapshotTracker = null;
+ private static final int SYNC_THRESHOLD = 10;
private final SyncStatusTracker initialSyncStatusTracker;
- private static final int SYNC_THRESHOLD = 10;
+ private final Procedure<ReplicatedLogEntry> appendAndPersistCallback = new Procedure<ReplicatedLogEntry>() {
+ @Override
+ public void apply(ReplicatedLogEntry logEntry) {
+ context.getReplicatedLog().captureSnapshotIfReady(logEntry);
+ }
+ };
+
+ private SnapshotTracker snapshotTracker = null;
+ private String leaderId;
+ private short leaderPayloadVersion;
public Follower(RaftActorContext context) {
- this(context, null);
+ this(context, null, (short)-1);
}
- public Follower(RaftActorContext context, String initialLeaderId) {
+ public Follower(RaftActorContext context, String initialLeaderId, short initialLeaderPayloadVersion) {
super(context, RaftState.Follower);
- leaderId = initialLeaderId;
+ this.leaderId = initialLeaderId;
+ this.leaderPayloadVersion = initialLeaderPayloadVersion;
initialSyncStatusTracker = new SyncStatusTracker(context.getActor(), getId(), SYNC_THRESHOLD);
- if(canStartElection()) {
- if (context.getPeerIds().isEmpty() && getLeaderId() == null) {
- actor().tell(ELECTION_TIMEOUT, actor());
- } else {
- scheduleElection(electionDuration());
- }
+ if (context.getPeerIds().isEmpty() && getLeaderId() == null) {
+ actor().tell(ElectionTimeout.INSTANCE, actor());
+ } else {
+ scheduleElection(electionDuration());
}
-
}
- private boolean isLogEntryPresent(long index){
- if(index == context.getReplicatedLog().getSnapshotIndex()){
- return true;
- }
+ @Override
+ public final String getLeaderId() {
+ return leaderId;
+ }
- ReplicatedLogEntry previousEntry = context.getReplicatedLog()
- .get(index);
+ @VisibleForTesting
+ protected final void setLeaderId(@Nullable final String leaderId) {
+ this.leaderId = leaderId;
+ }
- return previousEntry != null;
+ @Override
+ public short getLeaderPayloadVersion() {
+ return leaderPayloadVersion;
+ }
+ @VisibleForTesting
+ protected final void setLeaderPayloadVersion(short leaderPayloadVersion) {
+ this.leaderPayloadVersion = leaderPayloadVersion;
}
- private long getLogEntryTerm(long index){
- if(index == context.getReplicatedLog().getSnapshotIndex()){
- return context.getReplicatedLog().getSnapshotTerm();
+ private boolean isLogEntryPresent(long index){
+ if(context.getReplicatedLog().isInSnapshot(index)) {
+ return true;
}
- ReplicatedLogEntry previousEntry = context.getReplicatedLog()
- .get(index);
+ ReplicatedLogEntry entry = context.getReplicatedLog().get(index);
+ return entry != null;
- if(previousEntry != null){
- return previousEntry.getTerm();
- }
-
- return -1;
}
private void updateInitialSyncStatus(long currentLeaderCommit, String leaderId){
initialSyncStatusTracker.update(leaderId, currentLeaderCommit, context.getCommitIndex());
}
- @Override protected RaftActorBehavior handleAppendEntries(ActorRef sender,
- AppendEntries appendEntries) {
+ @Override
+ protected RaftActorBehavior handleAppendEntries(ActorRef sender, AppendEntries appendEntries) {
int numLogEntries = appendEntries.getEntries() != null ? appendEntries.getEntries().size() : 0;
if(LOG.isTraceEnabled()) {
// If we got here then we do appear to be talking to the leader
leaderId = appendEntries.getLeaderId();
-
- setLeaderPayloadVersion(appendEntries.getPayloadVersion());
+ leaderPayloadVersion = appendEntries.getPayloadVersion();
updateInitialSyncStatus(appendEntries.getLeaderCommit(), appendEntries.getLeaderId());
// First check if the logs are in sync or not
// Find the entry up until the one that is not in the follower's log
for (int i = 0;i < appendEntries.getEntries().size(); i++, addEntriesFrom++) {
ReplicatedLogEntry matchEntry = appendEntries.getEntries().get(i);
- ReplicatedLogEntry newEntry = context.getReplicatedLog().get(matchEntry.getIndex());
- if (newEntry == null) {
- //newEntry not found in the log
+ if(!isLogEntryPresent(matchEntry.getIndex())) {
+ // newEntry not found in the log
break;
}
- if (newEntry.getTerm() == matchEntry.getTerm()) {
+ 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;
}
matchEntry.getIndex());
// Entries do not match so remove all subsequent entries
- context.getReplicatedLog().removeFromAndPersist(matchEntry.getIndex());
+ 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.debug("{}: 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 this;
+ }
+
break;
} else {
sender.tell(new AppendEntriesReply(context.getId(), currentTerm(), false, lastIndex,
}
lastIndex = lastIndex();
- LOG.debug("{}: After cleanup entries to be added from = {}", logName(),
- (addEntriesFrom + lastIndex));
+ LOG.debug("{}: After cleanup, lastIndex: {}, entries to be added from: {}", logName(),
+ lastIndex, addEntriesFrom);
// 4. Append any new entries not already in the log
for (int i = addEntriesFrom; i < appendEntries.getEntries().size(); i++) {
LOG.debug("{}: Append entry to log {}", logName(), entry.getData());
- context.getReplicatedLog().appendAndPersist(entry);
+ context.getReplicatedLog().appendAndPersist(entry, appendAndPersistCallback);
if(entry.getData() instanceof ServerConfigurationPayload) {
context.updatePeerIds((ServerConfigurationPayload)entry.getData());
// The follower's log is out of sync because the Leader's
// prevLogIndex entry was not found in it's log
- LOG.debug("{}: The log is not empty but the prevLogIndex {} was not found in it",
- logName(), appendEntries.getPrevLogIndex());
+ LOG.debug("{}: The log is not empty but the prevLogIndex {} was not found in it - lastIndex: {}, snapshotIndex: {}",
+ logName(), appendEntries.getPrevLogIndex(), lastIndex, context.getReplicatedLog().getSnapshotIndex());
} else if (lastIndex > -1 && prevEntryPresent && prevLogTerm != appendEntries.getPrevLogTerm()) {
// The follower's log is out of sync because the Leader's
logName(), prevLogTerm, appendEntries.getPrevLogTerm());
} else if(appendEntries.getPrevLogIndex() == -1 && appendEntries.getPrevLogTerm() == -1
&& appendEntries.getReplicatedToAllIndex() != -1
- && !isLogEntryPresent(appendEntries.getReplicatedToAllIndex())
- && !context.getReplicatedLog().isInSnapshot(appendEntries.getReplicatedToAllIndex())) {
+ && !isLogEntryPresent(appendEntries.getReplicatedToAllIndex())) {
// This append entry comes from a leader who has it's log aggressively trimmed and so does not have
// the previous entry in it's in-memory journal
logName(), appendEntries.getReplicatedToAllIndex());
} else if(appendEntries.getPrevLogIndex() == -1 && appendEntries.getPrevLogTerm() == -1
&& appendEntries.getReplicatedToAllIndex() != -1 && numLogEntries > 0
- && !isLogEntryPresent(appendEntries.getEntries().get(0).getIndex() - 1)
- && !context.getReplicatedLog().isInSnapshot(appendEntries.getEntries().get(0).getIndex() - 1)) {
+ && !isLogEntryPresent(appendEntries.getEntries().get(0).getIndex() - 1)) {
LOG.debug(
"{}: Cannot append entries because the calculated previousIndex {} was not found in the in-memory journal",
logName(), appendEntries.getEntries().get(0).getIndex() - 1);
return outOfSync;
}
- @Override protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender,
+ @Override
+ protected RaftActorBehavior handleAppendEntriesReply(ActorRef sender,
AppendEntriesReply appendEntriesReply) {
return this;
}
- @Override protected RaftActorBehavior handleRequestVoteReply(ActorRef sender,
+ @Override
+ protected RaftActorBehavior handleRequestVoteReply(ActorRef sender,
RequestVoteReply requestVoteReply) {
return this;
}
- @Override public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
-
- Object message = fromSerializableMessage(originalMessage);
-
- if (message instanceof RaftRPC) {
- RaftRPC rpc = (RaftRPC) message;
- // If RPC request or response contains term T > currentTerm:
- // set currentTerm = T, convert to follower (§5.1)
- // This applies to all RPC messages and responses
- if (rpc.getTerm() > context.getTermInformation().getCurrentTerm()) {
- LOG.debug("{}: Term {} in \"{}\" message is greater than follower's term {} - updating term",
- logName(), rpc.getTerm(), rpc, context.getTermInformation().getCurrentTerm());
-
- context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
- }
- }
-
- if (message instanceof ElectionTimeout) {
- if(canStartElection()) {
+ @Override
+ public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
+ if (originalMessage instanceof ElectionTimeout) {
+ if (canStartElection()) {
LOG.debug("{}: Received ElectionTimeout - switching to Candidate", logName());
return internalSwitchBehavior(RaftState.Candidate);
} else {
+ setLeaderId(null);
+ scheduleElection(electionDuration());
return this;
}
+ }
+
+ final Object message = fromSerializableMessage(originalMessage);
+ if (!(message instanceof RaftRPC)) {
+ // The rest of the processing requires the message to be a RaftRPC
+ return null;
+ }
+
+ final RaftRPC rpc = (RaftRPC) message;
+ // If RPC request or response contains term T > currentTerm:
+ // set currentTerm = T, convert to follower (§5.1)
+ // This applies to all RPC messages and responses
+ if (rpc.getTerm() > context.getTermInformation().getCurrentTerm()) {
+ LOG.debug("{}: Term {} in \"{}\" message is greater than follower's term {} - updating term",
+ logName(), rpc.getTerm(), rpc, context.getTermInformation().getCurrentTerm());
+
+ context.getTermInformation().updateAndPersist(rpc.getTerm(), null);
+ }
- } else if (message instanceof InstallSnapshot) {
- InstallSnapshot installSnapshot = (InstallSnapshot) message;
+ if (rpc instanceof InstallSnapshot) {
+ InstallSnapshot installSnapshot = (InstallSnapshot) rpc;
handleInstallSnapshot(sender, installSnapshot);
+ scheduleElection(electionDuration());
+ return this;
}
- if(message instanceof RaftRPC && (!(message instanceof RequestVote) || (canGrantVote((RequestVote) message)))){
+ if (!(rpc instanceof RequestVote) || canGrantVote((RequestVote) rpc)) {
scheduleElection(electionDuration());
}
- return super.handleMessage(sender, message);
+ return super.handleMessage(sender, rpc);
}
private void handleInstallSnapshot(final ActorRef sender, InstallSnapshot installSnapshot) {
installSnapshot.getLastIncludedTerm(),
context.getTermInformation().getCurrentTerm(),
context.getTermInformation().getVotedFor(),
- context.getPeerServerInfo(true));
+ installSnapshot.getServerConfig().orNull());
ApplySnapshot.Callback applySnapshotCallback = new ApplySnapshot.Callback() {
@Override
}
@Override
- public void close() throws Exception {
+ public void close() {
stopElection();
}
Code Review / controller.git / blobdiff