clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/RemoteClusterControllerTask.java


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71

// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.clustercontroller.core;

import com.yahoo.vdslib.state.ClusterState;
import com.yahoo.vespa.clustercontroller.core.listeners.NodeAddedOrRemovedListener;
import com.yahoo.vespa.clustercontroller.core.listeners.NodeStateOrHostInfoChangeHandler;

public abstract class RemoteClusterControllerTask {

    public static class Context {
        public ContentCluster cluster;
        public ClusterState currentState;
        public MasterInterface masterInfo;
        public NodeStateOrHostInfoChangeHandler nodeStateOrHostInfoChangeHandler;
        public NodeAddedOrRemovedListener nodeAddedOrRemovedListener;
    }

    private final Object monitor = new Object();
    private boolean completed = false;

    public abstract void doRemoteFleetControllerTask(Context context);

    /**
     * If the task should _not_ be considered complete before a cluster state
     * version representing the changes made by the task has been ACKed by
     * all distributors.
     *
     * Note that if a task performs an idempotent state change (e.g. setting maintenance
     * mode on a node already in maintenance mode), the task may be considered complete
     * immediately if its effective changes have already been ACKed.
     */
    public boolean hasVersionAckDependency() { return false; }

    /**
     *  If the task response has been deferred due to hasVersionAckDependency(),
     *  handleLeadershipLost() will be invoked on the task if the cluster controller
     *  discovers it has lost leadership in the time between task execution and
     *  deferred response send time.
     *
     *  This method will also be invoked if the controller is signalled to shut down
     *  before the dependent cluster version has been published.
     */
    public void handleLeadershipLost() {}

    public boolean isCompleted() {
        synchronized (monitor) {
            return completed;
        }
    }

    /** This is called by the fleet controller. */
    public void notifyCompleted() {
        synchronized (monitor) {
            completed = true;
            monitor.notifyAll();
        }
    }

    public void waitForCompletion() {
        synchronized (monitor) {
            while (!completed) {
                try{
                    monitor.wait();
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        }
    }

}