com.hazelcast.internal.cluster.impl.ClusterMergeTask Maven / Gradle / Ivy

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Core Hazelcast Module
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/*
 * Copyright (c) 2008-2016, Hazelcast, Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.hazelcast.internal.cluster.impl;

import com.hazelcast.core.HazelcastInstanceNotActiveException;
import com.hazelcast.instance.GroupProperty;
import com.hazelcast.instance.LifecycleServiceImpl;
import com.hazelcast.instance.Node;
import com.hazelcast.spi.ManagedService;
import com.hazelcast.spi.SplitBrainHandlerService;
import com.hazelcast.util.Clock;
import com.hazelcast.util.EmptyStatement;

import java.util.Collection;
import java.util.LinkedList;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

import static com.hazelcast.core.LifecycleEvent.LifecycleState.MERGED;
import static com.hazelcast.core.LifecycleEvent.LifecycleState.MERGING;
import static com.hazelcast.util.Preconditions.isNotNull;

/**
 * ClusterMergeTask prepares {@code Node}'s internal state and its services
 * to merge and then triggers join process to the new cluster.
 * It is triggered on every member in the cluster when the master member detects
 * another cluster to join which it thinks current cluster is split from.
 *
 */
class ClusterMergeTask implements Runnable {

    private static final long MIN_WAIT_ON_FUTURE_TIMEOUT_MILLIS = TimeUnit.SECONDS.toMillis(10);

    private final Node node;

    ClusterMergeTask(Node node) {
        this.node = node;
    }

    public void run() {
        LifecycleServiceImpl lifecycleService = node.hazelcastInstance.getLifecycleService();
        lifecycleService.fireLifecycleEvent(MERGING);

        resetState();

        Collection tasks = collectMergeTasks();

        resetServices();

        rejoin();

        executeMergeTasks(tasks);

        if (node.isRunning() && node.joined()) {
            lifecycleService.fireLifecycleEvent(MERGED);
        }
    }

    private void resetState() {
        // reset node and membership state from now on this node won't be joined and won't have a master address
        node.reset();
        node.getClusterService().reset();
        // stop the connection-manager:
        // - all socket connections will be closed
        // - connection listening thread will stop
        // - no new connection will be established
        node.connectionManager.stop();

        // clear waiting operations in queue and notify invocations to retry
        node.nodeEngine.reset();
    }

    private Collection collectMergeTasks() {
        // gather merge tasks from services
        Collection services = node.nodeEngine.getServices(SplitBrainHandlerService.class);
        Collection tasks = new LinkedList();
        for (SplitBrainHandlerService service : services) {
            Runnable runnable = service.prepareMergeRunnable();
            if (runnable != null) {
                tasks.add(runnable);
            }
        }
        return tasks;
    }

    private void resetServices() {
        // reset all services to their initial state
        Collection managedServices = node.nodeEngine.getServices(ManagedService.class);
        for (ManagedService service : managedServices) {
            service.reset();
        }
    }

    private void rejoin() {
        // start connection-manager to setup and accept new connections
        node.connectionManager.start();
        // re-join to the target cluster
        node.join();
    }

    private void executeMergeTasks(Collection tasks) {
        // execute merge tasks
        Collection futures = new LinkedList();
        for (Runnable task : tasks) {
            Future f = node.nodeEngine.getExecutionService().submit("hz:system", task);
            futures.add(f);
        }
        long callTimeoutMillis = node.groupProperties.getMillis(GroupProperty.OPERATION_CALL_TIMEOUT_MILLIS);
        for (Future f : futures) {
            try {
                waitOnFutureInterruptible(f, callTimeoutMillis, TimeUnit.MILLISECONDS);
            } catch (HazelcastInstanceNotActiveException e) {
                EmptyStatement.ignore(e);
            } catch (Exception e) {
                node.getLogger(getClass()).severe("While merging...", e);
            }
        }
    }

    private  V waitOnFutureInterruptible(Future future, long timeout, TimeUnit timeUnit)
            throws ExecutionException, InterruptedException, TimeoutException {

        isNotNull(timeUnit, "timeUnit");
        long deadline = Clock.currentTimeMillis() + timeUnit.toMillis(timeout);
        while (true) {
            long localTimeoutMs = Math.min(MIN_WAIT_ON_FUTURE_TIMEOUT_MILLIS, deadline);
            try {
                return future.get(localTimeoutMs, TimeUnit.MILLISECONDS);
            } catch (TimeoutException t) {
                deadline -= localTimeoutMs;
                if (deadline <= 0) {
                    throw t;
                }
                if (!node.isRunning()) {
                    future.cancel(true);
                    throw new HazelcastInstanceNotActiveException();
                }
            }
        }
    }
}