co.cask.cdap.internal.app.runtime.service.InMemoryTwillContext.java Source code

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Here is the source code for co.cask.cdap.internal.app.runtime.service.InMemoryTwillContext.java

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/*
 * Copyright  2014 Cask Data, Inc.
 *
 * 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 co.cask.cdap.internal.app.runtime.service;

import co.cask.cdap.common.election.InMemoryElectionRegistry;
import com.google.common.collect.Sets;
import org.apache.twill.api.ElectionHandler;
import org.apache.twill.api.RunId;
import org.apache.twill.api.TwillContext;
import org.apache.twill.api.TwillRunnableSpecification;
import org.apache.twill.common.Cancellable;
import org.apache.twill.discovery.Discoverable;
import org.apache.twill.discovery.DiscoveryService;
import org.apache.twill.discovery.DiscoveryServiceClient;
import org.apache.twill.discovery.ServiceDiscovered;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.Closeable;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.util.Set;

/**
 * Implementation of {@link TwillContext} for the in memory twill runnable runner.
 */
final class InMemoryTwillContext implements TwillContext, Closeable {

    private static final Logger LOG = LoggerFactory.getLogger(InMemoryTwillContext.class);

    private final RunId runId;
    private final RunId applicationRunId;
    private final InetAddress host;
    private final String[] arguments;
    private final String[] applicationArguments;
    private final TwillRunnableSpecification specification;
    private final int instanceId;
    private final int virtualCores;
    private final int maxMemoryMB;
    private final DiscoveryServiceClient discoveryServiceClient;
    private final DiscoveryService discoveryService;
    private final InMemoryElectionRegistry electionRegistry;
    private final Set<Cancellable> electionCancels;

    private volatile int instanceCount;

    InMemoryTwillContext(RunId runId, RunId applicationRunId, InetAddress host, String[] arguments,
            String[] applicationArguments, TwillRunnableSpecification specification, int instanceId,
            int virtualCores, int maxMemoryMB, DiscoveryServiceClient discoveryServiceClient,
            DiscoveryService discoveryService, int instanceCount, InMemoryElectionRegistry electionRegistry) {
        this.runId = runId;
        this.applicationRunId = applicationRunId;
        this.host = host;
        this.arguments = arguments;
        this.applicationArguments = applicationArguments;
        this.specification = specification;
        this.instanceId = instanceId;
        this.virtualCores = virtualCores;
        this.maxMemoryMB = maxMemoryMB;
        this.discoveryServiceClient = discoveryServiceClient;
        this.discoveryService = discoveryService;
        this.instanceCount = instanceCount;
        this.electionRegistry = electionRegistry;
        this.electionCancels = Sets.newCopyOnWriteArraySet();
    }

    @Override
    public RunId getRunId() {
        return runId;
    }

    @Override
    public RunId getApplicationRunId() {
        return applicationRunId;
    }

    @Override
    public int getInstanceCount() {
        return instanceCount;
    }

    public void setInstanceCount(int instanceCount) {
        this.instanceCount = instanceCount;
    }

    @Override
    public InetAddress getHost() {
        return host;
    }

    @Override
    public String[] getArguments() {
        return arguments;
    }

    @Override
    public String[] getApplicationArguments() {
        return applicationArguments;
    }

    @Override
    public TwillRunnableSpecification getSpecification() {
        return specification;
    }

    @Override
    public int getInstanceId() {
        return instanceId;
    }

    @Override
    public int getVirtualCores() {
        return virtualCores;
    }

    @Override
    public int getMaxMemoryMB() {
        return maxMemoryMB;
    }

    @Override
    public ServiceDiscovered discover(String name) {
        return discoveryServiceClient.discover(name);
    }

    @Override
    public Cancellable electLeader(String name, ElectionHandler participantHandler) {
        // Namespace it under the application runId
        String electionName = String.format("%s.%s", applicationRunId.getId(), name);

        final Cancellable delegate = electionRegistry.join(electionName, participantHandler);
        Cancellable cancel = new Cancellable() {
            @Override
            public void cancel() {
                try {
                    delegate.cancel();
                } finally {
                    electionCancels.remove(this);
                }
            }
        };

        electionCancels.add(cancel);
        return cancel;
    }

    @Override
    public Cancellable announce(final String serviceName, final int port) {
        return discoveryService.register(new Discoverable() {
            @Override
            public String getName() {
                return serviceName;
            }

            @Override
            public InetSocketAddress getSocketAddress() {
                return new InetSocketAddress(host, port);
            }
        });
    }

    @Override
    public void close() throws IOException {
        for (Cancellable c : electionCancels) {
            try {
                c.cancel();
            } catch (Throwable t) {
                LOG.error("Exception when withdraw from leader election.", t);
            }
        }
    }
}