com.inmobi.conduit.zookeeper.CuratorLeaderManager.java Source code

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Here is the source code for com.inmobi.conduit.zookeeper.CuratorLeaderManager.java

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/*
* 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.inmobi.conduit.zookeeper;

import java.net.InetAddress;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.inmobi.conduit.Service;
import com.netflix.curator.framework.CuratorFramework;
import com.netflix.curator.framework.CuratorFrameworkFactory;
import com.netflix.curator.framework.recipes.leader.LeaderSelector;
import com.netflix.curator.framework.recipes.leader.LeaderSelectorListener;
import com.netflix.curator.framework.state.ConnectionState;
import com.netflix.curator.retry.RetryOneTime;

public class CuratorLeaderManager implements LeaderSelectorListener {
    private static final Log LOG = LogFactory.getLog(CuratorLeaderManager.class);
    private final Service conduit;
    private final String conduitClusterId;
    private final String zkConnectString;
    private CuratorFramework client;
    private LeaderSelector leaderSelector;

    public CuratorLeaderManager(Service conduit, String conduitClusterId, String zkConnectString) {
        this.conduit = conduit;
        this.conduitClusterId = conduitClusterId;
        this.zkConnectString = zkConnectString;
    }

    public void start() throws Exception {
        String zkPath = "/conduit/" + conduitClusterId;
        this.client = CuratorFrameworkFactory.newClient(zkConnectString, new RetryOneTime(3));
        this.leaderSelector = new LeaderSelector(client, zkPath, this);
        connect();
    }

    private void connect() throws Exception {
        client.start();// connect to ZK
        LOG.info("becomeLeader :: connect to ZK [" + zkConnectString + "]");
        leaderSelector.setId(InetAddress.getLocalHost().getHostName());
        leaderSelector.start();
        LOG.info("started the LeaderSelector");
    }

    @Override
    public void takeLeadership(CuratorFramework curatorFramework) throws Exception {
        LOG.info("Became Leader..starting to do work");
        // This method shouldn't return till you want to release leadership
        conduit.start();
    }

    @Override
    public void stateChanged(CuratorFramework curatorFramework, ConnectionState connectionState) {
        if (connectionState == ConnectionState.LOST) {
            try {
                conduit.stop();
            } catch (Exception e1) {
                LOG.warn("Error while stopping conduit service", e1);
            }
            LOG.info("Releasing leadership..connection LOST");
            try {
                LOG.info("Trying reconnect..");
                connect();
            } catch (Exception e) {
                LOG.warn("Error in attempting to connect to ZK after releasing leadership", e);
            }
        }
    }

    public void close() {
        if (leaderSelector != null) {
            leaderSelector.close();
        }
        if (client != null) {
            client.close();
        }
    }

}