2 * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.controller.cluster.raft.behaviors;
10 import akka.actor.ActorRef;
11 import akka.actor.Cancellable;
12 import com.google.common.annotations.VisibleForTesting;
13 import com.google.common.base.Preconditions;
14 import org.opendaylight.controller.cluster.raft.RaftActorContext;
15 import org.opendaylight.controller.cluster.raft.base.messages.IsolatedLeaderCheck;
16 import scala.concurrent.duration.FiniteDuration;
19 * The behavior of a RaftActor when it is in the Leader state
23 * <li> Upon election: send initial empty AppendEntries RPCs
24 * (heartbeat) to each server; repeat during idle periods to
25 * prevent election timeouts (§5.2)
26 * <li> If command received from client: append entry to local log,
27 * respond after entry applied to state machine (§5.3)
28 * <li> If last log index ≥ nextIndex for a follower: send
29 * AppendEntries RPC with log entries starting at nextIndex
31 * <li> If successful: update nextIndex and matchIndex for
33 * <li> If AppendEntries fails because of log inconsistency:
34 * decrement nextIndex and retry (§5.3)
36 * <li> If there exists an N such that N > commitIndex, a majority
37 * of matchIndex[i] ≥ N, and log[N].term == currentTerm:
38 * set commitIndex = N (§5.3, §5.4).
40 public class Leader extends AbstractLeader {
41 private Cancellable installSnapshotSchedule = null;
42 private Cancellable isolatedLeaderCheckSchedule = null;
44 public Leader(RaftActorContext context) {
47 scheduleIsolatedLeaderCheck(
48 new FiniteDuration(context.getConfigParams().getHeartBeatInterval().length() * 10,
49 context.getConfigParams().getHeartBeatInterval().unit()));
52 @Override public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
53 Preconditions.checkNotNull(sender, "sender should not be null");
55 if (originalMessage instanceof IsolatedLeaderCheck) {
56 if (isLeaderIsolated()) {
57 LOG.info("{}: At least {} followers need to be active, Switching {} from Leader to IsolatedLeader",
58 context.getId(), minIsolatedLeaderPeerCount, leaderId);
59 return switchBehavior(new IsolatedLeader(context));
63 return super.handleMessage(sender, originalMessage);
66 protected void stopIsolatedLeaderCheckSchedule() {
67 if (isolatedLeaderCheckSchedule != null && !isolatedLeaderCheckSchedule.isCancelled()) {
68 isolatedLeaderCheckSchedule.cancel();
72 protected void scheduleIsolatedLeaderCheck(FiniteDuration isolatedCheckInterval) {
73 isolatedLeaderCheckSchedule = context.getActorSystem().scheduler().schedule(isolatedCheckInterval, isolatedCheckInterval,
74 context.getActor(), new IsolatedLeaderCheck(),
75 context.getActorSystem().dispatcher(), context.getActor());
79 public void close() throws Exception {
80 stopIsolatedLeaderCheckSchedule();
85 void markFollowerActive(String followerId) {
86 getFollower(followerId).markFollowerActive();
90 void markFollowerInActive(String followerId) {
91 getFollower(followerId).markFollowerInActive();