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
9 package org.opendaylight.controller.cluster.raft.behaviors;
11 import akka.actor.ActorRef;
12 import akka.actor.Cancellable;
13 import com.google.common.annotations.VisibleForTesting;
14 import com.google.common.base.Preconditions;
15 import org.opendaylight.controller.cluster.raft.RaftActorContext;
16 import org.opendaylight.controller.cluster.raft.base.messages.InitiateInstallSnapshot;
17 import org.opendaylight.controller.cluster.raft.base.messages.IsolatedLeaderCheck;
18 import scala.concurrent.duration.FiniteDuration;
21 * The behavior of a RaftActor when it is in the Leader state
25 * <li> Upon election: send initial empty AppendEntries RPCs
26 * (heartbeat) to each server; repeat during idle periods to
27 * prevent election timeouts (§5.2)
28 * <li> If command received from client: append entry to local log,
29 * respond after entry applied to state machine (§5.3)
30 * <li> If last log index ≥ nextIndex for a follower: send
31 * AppendEntries RPC with log entries starting at nextIndex
33 * <li> If successful: update nextIndex and matchIndex for
35 * <li> If AppendEntries fails because of log inconsistency:
36 * decrement nextIndex and retry (§5.3)
38 * <li> If there exists an N such that N > commitIndex, a majority
39 * of matchIndex[i] ≥ N, and log[N].term == currentTerm:
40 * set commitIndex = N (§5.3, §5.4).
42 public class Leader extends AbstractLeader {
43 private Cancellable installSnapshotSchedule = null;
44 private Cancellable isolatedLeaderCheckSchedule = null;
46 public Leader(RaftActorContext context) {
49 scheduleInstallSnapshotCheck(context.getConfigParams().getIsolatedCheckInterval());
51 scheduleIsolatedLeaderCheck(
52 new FiniteDuration(context.getConfigParams().getHeartBeatInterval().length() * 10,
53 context.getConfigParams().getHeartBeatInterval().unit()));
56 @Override public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
57 Preconditions.checkNotNull(sender, "sender should not be null");
59 if (originalMessage instanceof IsolatedLeaderCheck) {
60 if (isLeaderIsolated()) {
61 LOG.info("At least {} followers need to be active, Switching {} from Leader to IsolatedLeader",
62 minIsolatedLeaderPeerCount, leaderId);
63 return switchBehavior(new IsolatedLeader(context));
67 return super.handleMessage(sender, originalMessage);
70 protected void stopInstallSnapshotSchedule() {
71 if (installSnapshotSchedule != null && !installSnapshotSchedule.isCancelled()) {
72 installSnapshotSchedule.cancel();
76 protected void scheduleInstallSnapshotCheck(FiniteDuration interval) {
77 if(followers.size() == 0){
78 // Optimization - do not bother scheduling a heartbeat as there are
83 stopInstallSnapshotSchedule();
85 // Schedule a message to send append entries to followers that can
86 // accept an append entries with some data in it
87 installSnapshotSchedule =
88 context.getActorSystem().scheduler().scheduleOnce(
90 context.getActor(), new InitiateInstallSnapshot(),
91 context.getActorSystem().dispatcher(), context.getActor());
94 protected void stopIsolatedLeaderCheckSchedule() {
95 if (isolatedLeaderCheckSchedule != null && !isolatedLeaderCheckSchedule.isCancelled()) {
96 isolatedLeaderCheckSchedule.cancel();
100 protected void scheduleIsolatedLeaderCheck(FiniteDuration isolatedCheckInterval) {
101 isolatedLeaderCheckSchedule = context.getActorSystem().scheduler().schedule(isolatedCheckInterval, isolatedCheckInterval,
102 context.getActor(), new IsolatedLeaderCheck(),
103 context.getActorSystem().dispatcher(), context.getActor());
106 @Override public void close() throws Exception {
107 stopInstallSnapshotSchedule();
108 stopIsolatedLeaderCheckSchedule();
113 void markFollowerActive(String followerId) {
114 followerToLog.get(followerId).markFollowerActive();
118 void markFollowerInActive(String followerId) {
119 followerToLog.get(followerId).markFollowerInActive();