Merge "Removing { } from NormalizedNodeJsonBodyWriter"
[controller.git] / opendaylight / md-sal / sal-akka-raft / src / main / java / org / opendaylight / controller / cluster / raft / behaviors / Leader.java
1 /*
2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
3  *
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
7  */
8 package org.opendaylight.controller.cluster.raft.behaviors;
9
10 import akka.actor.ActorRef;
11 import com.google.common.annotations.VisibleForTesting;
12 import com.google.common.base.Preconditions;
13 import com.google.common.base.Stopwatch;
14 import java.util.concurrent.TimeUnit;
15 import org.opendaylight.controller.cluster.raft.RaftActorContext;
16 import org.opendaylight.controller.cluster.raft.base.messages.IsolatedLeaderCheck;
17
18 /**
19  * The behavior of a RaftActor when it is in the Leader state
20  * <p/>
21  * Leaders:
22  * <ul>
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
30  * <ul>
31  * <li> If successful: update nextIndex and matchIndex for
32  * follower (§5.3)
33  * <li> If AppendEntries fails because of log inconsistency:
34  * decrement nextIndex and retry (§5.3)
35  * </ul>
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).
39  */
40 public class Leader extends AbstractLeader {
41     private static final IsolatedLeaderCheck ISOLATED_LEADER_CHECK = new IsolatedLeaderCheck();
42     private final Stopwatch isolatedLeaderCheck;
43
44     public Leader(RaftActorContext context) {
45         super(context);
46         isolatedLeaderCheck = Stopwatch.createStarted();
47     }
48
49     @Override public RaftActorBehavior handleMessage(ActorRef sender, Object originalMessage) {
50         Preconditions.checkNotNull(sender, "sender should not be null");
51
52         if (originalMessage instanceof IsolatedLeaderCheck) {
53             if (isLeaderIsolated()) {
54                 LOG.warn("{}: At least {} followers need to be active, Switching {} from Leader to IsolatedLeader",
55                         context.getId(), minIsolatedLeaderPeerCount, leaderId);
56
57                 return switchBehavior(new IsolatedLeader(context));
58             }
59         }
60
61         return super.handleMessage(sender, originalMessage);
62     }
63
64     @Override
65     protected void beforeSendHeartbeat(){
66         if(isolatedLeaderCheck.elapsed(TimeUnit.MILLISECONDS) > context.getConfigParams().getIsolatedCheckIntervalInMillis()){
67             context.getActor().tell(ISOLATED_LEADER_CHECK, context.getActor());
68             isolatedLeaderCheck.reset().start();
69         }
70
71     }
72
73     @Override
74     public void close() throws Exception {
75         super.close();
76     }
77
78     @VisibleForTesting
79     void markFollowerActive(String followerId) {
80         getFollower(followerId).markFollowerActive();
81     }
82
83     @VisibleForTesting
84     void markFollowerInActive(String followerId) {
85         getFollower(followerId).markFollowerInActive();
86     }
87 }

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