/*
* Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.controller.cluster.raft.behaviors;
import akka.actor.ActorRef;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
import com.google.common.base.Stopwatch;
import java.util.concurrent.TimeUnit;
import org.opendaylight.controller.cluster.raft.RaftActorContext;
import org.opendaylight.controller.cluster.raft.RaftState;
import org.opendaylight.controller.cluster.raft.base.messages.IsolatedLeaderCheck;
/**
* The behavior of a RaftActor when it is in the Leader state
*
* Leaders:
*
* - Upon election: send initial empty AppendEntries RPCs
* (heartbeat) to each server; repeat during idle periods to
* prevent election timeouts (§5.2)
*
- If command received from client: append entry to local log,
* respond after entry applied to state machine (§5.3)
*
- If last log index ≥ nextIndex for a follower: send
* AppendEntries RPC with log entries starting at nextIndex
*
* - If successful: update nextIndex and matchIndex for
* follower (§5.3)
*
- If AppendEntries fails because of log inconsistency:
* decrement nextIndex and retry (§5.3)
*
* - If there exists an N such that N > commitIndex, a majority
* of matchIndex[i] ≥ N, and log[N].term == currentTerm:
* set commitIndex = N (§5.3, §5.4).
*/
public class Leader extends AbstractLeader {
private static final IsolatedLeaderCheck ISOLATED_LEADER_CHECK = new IsolatedLeaderCheck();
private final Stopwatch isolatedLeaderCheck;
public Leader(RaftActorContext context) {
super(context);
isolatedLeaderCheck = Stopwatch.createStarted();
}
@Override public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
Preconditions.checkNotNull(sender, "sender should not be null");
if (originalMessage instanceof IsolatedLeaderCheck) {
if (isLeaderIsolated()) {
LOG.warn("{}: At least {} followers need to be active, Switching {} from Leader to IsolatedLeader",
context.getId(), getMinIsolatedLeaderPeerCount(), leaderId);
return internalSwitchBehavior(RaftState.IsolatedLeader);
}
}
return super.handleMessage(sender, originalMessage);
}
@Override
protected void beforeSendHeartbeat(){
if(isolatedLeaderCheck.elapsed(TimeUnit.MILLISECONDS) > context.getConfigParams().getIsolatedCheckIntervalInMillis()){
context.getActor().tell(ISOLATED_LEADER_CHECK, context.getActor());
isolatedLeaderCheck.reset().start();
}
}
@Override
public void close() throws Exception {
super.close();
}
@VisibleForTesting
void markFollowerActive(String followerId) {
getFollower(followerId).markFollowerActive();
}
@VisibleForTesting
void markFollowerInActive(String followerId) {
getFollower(followerId).markFollowerInActive();
}
}