import akka.actor.ActorRef;
import akka.actor.Cancellable;
+import org.opendaylight.controller.cluster.raft.ClientRequestTracker;
import org.opendaylight.controller.cluster.raft.RaftActorContext;
import org.opendaylight.controller.cluster.raft.RaftState;
import org.opendaylight.controller.cluster.raft.ReplicatedLogEntry;
-import org.opendaylight.controller.cluster.raft.internal.messages.ElectionTimeout;
+import org.opendaylight.controller.cluster.raft.SerializationUtils;
+import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
+import org.opendaylight.controller.cluster.raft.base.messages.ElectionTimeout;
import org.opendaylight.controller.cluster.raft.messages.AppendEntries;
import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
-import org.opendaylight.controller.cluster.raft.messages.RaftRPC;
import org.opendaylight.controller.cluster.raft.messages.RequestVote;
import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
import scala.concurrent.duration.FiniteDuration;
protected final RaftActorContext context;
/**
- * The maximum election time variance
- */
- private static final int ELECTION_TIME_MAX_VARIANCE = 100;
-
- /**
- * The interval at which a heart beat message will be sent to the remote
- * RaftActor
- * <p/>
- * Since this is set to 100 milliseconds the Election timeout should be
- * at least 200 milliseconds
- */
- protected static final FiniteDuration HEART_BEAT_INTERVAL =
- new FiniteDuration(100, TimeUnit.MILLISECONDS);
-
- /**
- * The interval in which a new election would get triggered if no leader is found
+ *
*/
- private static final long ELECTION_TIME_INTERVAL =
- HEART_BEAT_INTERVAL.toMillis() * 2;
+ private Cancellable electionCancel = null;
/**
*
*/
-
- private Cancellable electionCancel = null;
+ protected String leaderId = null;
protected AbstractRaftActorBehavior(RaftActorContext context) {
*
* @param sender The actor that sent this message
* @param appendEntries The AppendEntries message
- * @param suggestedState The state that the RaftActor should be in based
- * on the base class's processing of the AppendEntries
- * message
* @return
*/
protected abstract RaftState handleAppendEntries(ActorRef sender,
- AppendEntries appendEntries, RaftState suggestedState);
+ AppendEntries appendEntries);
+ /**
+ * appendEntries first processes the AppendEntries message and then
+ * delegates handling to a specific behavior
+ *
+ * @param sender
+ * @param appendEntries
+ * @return
+ */
protected RaftState appendEntries(ActorRef sender,
- AppendEntries appendEntries, RaftState raftState){
+ AppendEntries appendEntries) {
// 1. Reply false if term < currentTerm (§5.1)
- if(appendEntries.getTerm() < currentTerm()){
- sender.tell(new AppendEntriesReply(currentTerm(), false), actor());
+ if (appendEntries.getTerm() < currentTerm()) {
+ context.getLogger().debug(
+ "Cannot append entries because sender term " + appendEntries
+ .getTerm() + " is less than " + currentTerm());
+ sender.tell(
+ new AppendEntriesReply(context.getId(), currentTerm(), false,
+ lastIndex(), lastTerm()), actor()
+ );
return state();
}
- // 2. Reply false if log doesn’t contain an entry at prevLogIndex
- // whose term matches prevLogTerm (§5.3)
- ReplicatedLogEntry previousEntry = context.getReplicatedLog()
- .get(appendEntries.getPrevLogIndex());
-
- if(previousEntry == null || previousEntry.getTerm() != appendEntries.getPrevLogTerm()){
- sender.tell(new AppendEntriesReply(currentTerm(), false), actor());
- return state();
- }
-
- if(appendEntries.getEntries() != null) {
- // 3. If an existing entry conflicts with a new one (same index
- // but different terms), delete the existing entry and all that
- // follow it (§5.3)
- int addEntriesFrom = 0;
- for (int i = 0;
- i < appendEntries.getEntries().size(); i++, addEntriesFrom++) {
- ReplicatedLogEntry newEntry = context.getReplicatedLog()
- .get(i + 1);
-
- if (newEntry != null && newEntry.getTerm() == appendEntries.getEntries().get(i).getTerm()){
- break;
- }
- if (newEntry != null && newEntry.getTerm() != appendEntries
- .getEntries().get(i).getTerm()) {
- context.getReplicatedLog().removeFrom(i + 1);
- break;
- }
- }
-
- // 4. Append any new entries not already in the log
- for (int i = addEntriesFrom;
- i < appendEntries.getEntries().size(); i++) {
- context.getReplicatedLog()
- .append(appendEntries.getEntries().get(i));
- }
- }
-
-
- // 5. If leaderCommit > commitIndex, set commitIndex =
- // min(leaderCommit, index of last new entry)
- context.setCommitIndex(Math.min(appendEntries.getLeaderCommit(),
- context.getReplicatedLog().last().getIndex()));
-
- // If commitIndex > lastApplied: increment lastApplied, apply
- // log[lastApplied] to state machine (§5.3)
- if (appendEntries.getLeaderCommit() > context.getLastApplied()) {
- applyLogToStateMachine(appendEntries.getLeaderCommit());
- }
-
- sender.tell(new AppendEntriesReply(currentTerm(), true), actor());
- return handleAppendEntries(sender, appendEntries, raftState);
+ return handleAppendEntries(sender, appendEntries);
}
/**
*
* @param sender The actor that sent this message
* @param appendEntriesReply The AppendEntriesReply message
- * @param suggestedState The state that the RaftActor should be in based
- * on the base class's processing of the
- * AppendEntriesReply message
* @return
*/
-
protected abstract RaftState handleAppendEntriesReply(ActorRef sender,
- AppendEntriesReply appendEntriesReply, RaftState suggestedState);
+ AppendEntriesReply appendEntriesReply);
+ /**
+ * requestVote handles the RequestVote message. This logic is common
+ * for all behaviors
+ *
+ * @param sender
+ * @param requestVote
+ * @return
+ */
protected RaftState requestVote(ActorRef sender,
- RequestVote requestVote, RaftState suggestedState) {
+ RequestVote requestVote) {
+
+
+ context.getLogger().debug(requestVote.toString());
boolean grantVote = false;
if (requestVote.getLastLogTerm() > lastTerm()) {
candidateLatest = true;
} else if ((requestVote.getLastLogTerm() == lastTerm())
- && requestVote.getLastLogIndex() >= lastTerm()) {
+ && requestVote.getLastLogIndex() >= lastIndex()) {
candidateLatest = true;
}
if (candidateLatest) {
grantVote = true;
- context.getTermInformation().update(requestVote.getTerm(),
+ context.getTermInformation().updateAndPersist(requestVote.getTerm(),
requestVote.getCandidateId());
}
}
sender.tell(new RequestVoteReply(currentTerm(), grantVote), actor());
- return suggestedState;
+ return state();
}
/**
*
* @param sender The actor that sent this message
* @param requestVoteReply The RequestVoteReply message
- * @param suggestedState The state that the RaftActor should be in based
- * on the base class's processing of the RequestVote
- * message
* @return
*/
-
protected abstract RaftState handleRequestVoteReply(ActorRef sender,
- RequestVoteReply requestVoteReply, RaftState suggestedState);
+ RequestVoteReply requestVoteReply);
/**
- * @return The derived class should return the state that corresponds to
- * it's behavior
+ * Creates a random election duration
+ *
+ * @return
*/
- protected abstract RaftState state();
-
protected FiniteDuration electionDuration() {
- long variance = new Random().nextInt(ELECTION_TIME_MAX_VARIANCE);
- return new FiniteDuration(ELECTION_TIME_INTERVAL + variance,
- TimeUnit.MILLISECONDS);
+ long variance = new Random().nextInt(context.getConfigParams().getElectionTimeVariance());
+ return context.getConfigParams().getElectionTimeOutInterval().$plus(
+ new FiniteDuration(variance, TimeUnit.MILLISECONDS));
}
- protected void scheduleElection(FiniteDuration interval) {
-
+ /**
+ * stop the scheduled election
+ */
+ protected void stopElection() {
if (electionCancel != null && !electionCancel.isCancelled()) {
electionCancel.cancel();
}
+ }
+
+ /**
+ * schedule a new election
+ *
+ * @param interval
+ */
+ protected void scheduleElection(FiniteDuration interval) {
+ stopElection();
// Schedule an election. When the scheduler triggers an ElectionTimeout
// message is sent to itself
context.getActorSystem().dispatcher(), context.getActor());
}
+ /**
+ * Get the current term
+ * @return
+ */
protected long currentTerm() {
return context.getTermInformation().getCurrentTerm();
}
+ /**
+ * Get the candidate for whom we voted in the current term
+ * @return
+ */
protected String votedFor() {
return context.getTermInformation().getVotedFor();
}
+ /**
+ * Get the actor associated with this behavior
+ * @return
+ */
protected ActorRef actor() {
return context.getActor();
}
+ /**
+ * Get the term from the last entry in the log
+ *
+ * @return
+ */
protected long lastTerm() {
- return context.getReplicatedLog().last().getTerm();
+ return context.getReplicatedLog().lastTerm();
}
+ /**
+ * Get the index from the last entry in the log
+ *
+ * @return
+ */
protected long lastIndex() {
- return context.getReplicatedLog().last().getIndex();
+ return context.getReplicatedLog().lastIndex();
}
+ /**
+ * Find the client request tracker for a specific logIndex
+ *
+ * @param logIndex
+ * @return
+ */
+ protected ClientRequestTracker findClientRequestTracker(long logIndex) {
+ return null;
+ }
- @Override
- public RaftState handleMessage(ActorRef sender, Object message) {
- RaftState raftState = state();
- if (message instanceof RaftRPC) {
- raftState = applyTerm((RaftRPC) message);
- }
- if (message instanceof AppendEntries) {
- raftState = appendEntries(sender, (AppendEntries) message,
- raftState);
- } else if (message instanceof AppendEntriesReply) {
- raftState =
- handleAppendEntriesReply(sender, (AppendEntriesReply) message,
- raftState);
- } else if (message instanceof RequestVote) {
- raftState =
- requestVote(sender, (RequestVote) message, raftState);
- } else if (message instanceof RequestVoteReply) {
- raftState =
- handleRequestVoteReply(sender, (RequestVoteReply) message,
- raftState);
+ /**
+ * Find the log index from the previous to last entry in the log
+ *
+ * @return
+ */
+ protected long prevLogIndex(long index){
+ ReplicatedLogEntry prevEntry =
+ context.getReplicatedLog().get(index - 1);
+ if (prevEntry != null) {
+ return prevEntry.getIndex();
}
- return raftState;
+ return -1;
}
- private RaftState applyTerm(RaftRPC rpc) {
- // 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()) {
- context.getTermInformation().update(rpc.getTerm(), null);
- return RaftState.Follower;
+ /**
+ * Find the log term from the previous to last entry in the log
+ * @return
+ */
+ protected long prevLogTerm(long index){
+ ReplicatedLogEntry prevEntry =
+ context.getReplicatedLog().get(index - 1);
+ if (prevEntry != null) {
+ return prevEntry.getTerm();
}
- return state();
+ return -1;
}
- private void applyLogToStateMachine(long index) {
+ /**
+ * Apply the provided index to the state machine
+ *
+ * @param index a log index that is known to be committed
+ */
+ protected void applyLogToStateMachine(final long index) {
+ // Now maybe we apply to the state machine
+ for (long i = context.getLastApplied() + 1;
+ i < index + 1; i++) {
+ ActorRef clientActor = null;
+ String identifier = null;
+ ClientRequestTracker tracker = findClientRequestTracker(i);
+
+ if (tracker != null) {
+ clientActor = tracker.getClientActor();
+ identifier = tracker.getIdentifier();
+ }
+ ReplicatedLogEntry replicatedLogEntry =
+ context.getReplicatedLog().get(i);
+
+ if (replicatedLogEntry != null) {
+ actor().tell(new ApplyState(clientActor, identifier,
+ replicatedLogEntry), actor());
+ } else {
+ context.getLogger().error(
+ "Missing index " + i + " from log. Cannot apply state.");
+ }
+ }
// Send a local message to the local RaftActor (it's derived class to be
// specific to apply the log to it's index)
+ context.getLogger().debug("Setting last applied to {}", index);
context.setLastApplied(index);
}
+ protected Object fromSerializableMessage(Object serializable){
+ return SerializationUtils.fromSerializable(serializable);
+ }
+ @Override
+ public RaftState handleMessage(ActorRef sender, Object message) {
+ if (message instanceof AppendEntries) {
+ return appendEntries(sender, (AppendEntries) message);
+ } else if (message instanceof AppendEntriesReply) {
+ return handleAppendEntriesReply(sender, (AppendEntriesReply) message);
+ } else if (message instanceof RequestVote) {
+ return requestVote(sender, (RequestVote) message);
+ } else if (message instanceof RequestVoteReply) {
+ return handleRequestVoteReply(sender, (RequestVoteReply) message);
+ }
+ return state();
+ }
+
+ @Override public String getLeaderId() {
+ return leaderId;
+ }
}
Code Review / controller.git / blobdiff