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.InitiateInstallSnapshot;
16 import org.opendaylight.controller.cluster.raft.base.messages.IsolatedLeaderCheck;
17 import scala.concurrent.duration.FiniteDuration;
20 * The behavior of a RaftActor when it is in the Leader state
24 * <li> Upon election: send initial empty AppendEntries RPCs
25 * (heartbeat) to each server; repeat during idle periods to
26 * prevent election timeouts (§5.2)
27 * <li> If command received from client: append entry to local log,
28 * respond after entry applied to state machine (§5.3)
29 * <li> If last log index ≥ nextIndex for a follower: send
30 * AppendEntries RPC with log entries starting at nextIndex
32 * <li> If successful: update nextIndex and matchIndex for
34 * <li> If AppendEntries fails because of log inconsistency:
35 * decrement nextIndex and retry (§5.3)
37 * <li> If there exists an N such that N > commitIndex, a majority
38 * of matchIndex[i] ≥ N, and log[N].term == currentTerm:
39 * set commitIndex = N (§5.3, §5.4).
41 public class Leader extends AbstractLeader {
42 private Cancellable installSnapshotSchedule = null;
43 private Cancellable isolatedLeaderCheckSchedule = null;
45 public Leader(RaftActorContext context) {
48 scheduleInstallSnapshotCheck(context.getConfigParams().getIsolatedCheckInterval());
50 scheduleIsolatedLeaderCheck(
51 new FiniteDuration(context.getConfigParams().getHeartBeatInterval().length() * 10,
52 context.getConfigParams().getHeartBeatInterval().unit()));
55 @Override public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
56 Preconditions.checkNotNull(sender, "sender should not be null");
58 if (originalMessage instanceof IsolatedLeaderCheck) {
59 if (isLeaderIsolated()) {
60 LOG.info("{}: At least {} followers need to be active, Switching {} from Leader to IsolatedLeader",
61 context.getId(), minIsolatedLeaderPeerCount, leaderId);
62 return switchBehavior(new IsolatedLeader(context));
66 return super.handleMessage(sender, originalMessage);
69 protected void stopInstallSnapshotSchedule() {
70 if (installSnapshotSchedule != null && !installSnapshotSchedule.isCancelled()) {
71 installSnapshotSchedule.cancel();
75 protected void scheduleInstallSnapshotCheck(FiniteDuration interval) {
76 if (getFollowerIds().isEmpty()) {
77 // Optimization - do not bother scheduling a heartbeat as there are
82 stopInstallSnapshotSchedule();
84 // Schedule a message to send append entries to followers that can
85 // accept an append entries with some data in it
86 installSnapshotSchedule =
87 context.getActorSystem().scheduler().scheduleOnce(
89 context.getActor(), new InitiateInstallSnapshot(),
90 context.getActorSystem().dispatcher(), context.getActor());
93 protected void stopIsolatedLeaderCheckSchedule() {
94 if (isolatedLeaderCheckSchedule != null && !isolatedLeaderCheckSchedule.isCancelled()) {
95 isolatedLeaderCheckSchedule.cancel();
99 protected void scheduleIsolatedLeaderCheck(FiniteDuration isolatedCheckInterval) {
100 isolatedLeaderCheckSchedule = context.getActorSystem().scheduler().schedule(isolatedCheckInterval, isolatedCheckInterval,
101 context.getActor(), new IsolatedLeaderCheck(),
102 context.getActorSystem().dispatcher(), context.getActor());
106 public void close() throws Exception {
107 stopInstallSnapshotSchedule();
108 stopIsolatedLeaderCheckSchedule();
113 void markFollowerActive(String followerId) {
114 getFollower(followerId).markFollowerActive();
118 void markFollowerInActive(String followerId) {
119 getFollower(followerId).markFollowerInActive();