org.apache.pig.piggybank.squeal.spout.RMQSpout.java Source code

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Here is the source code for org.apache.pig.piggybank.squeal.spout.RMQSpout.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.pig.piggybank.squeal.spout;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.QueueingConsumer;
import com.rabbitmq.client.QueueingConsumer.Delivery;
import backtype.storm.spout.SpoutOutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichSpout;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Values;

public class RMQSpout extends BaseRichSpout {
    ConnectionFactory factory;
    Connection connection;
    Channel channel;
    private QueueingConsumer consumer;
    private String rabbitURI;
    private String exchangeName;
    private SpoutOutputCollector collector;
    private String _queueName;
    private Random r;
    private Map<Integer, Long> out_id = new HashMap<Integer, Long>();
    int flush_counter = 0;
    int QOS = 250;

    public RMQSpout(String rabbitURI, String exchangeName) {
        this(rabbitURI, exchangeName, null);
    }

    public RMQSpout(String rabbitURI, String exchangeName, String queueName) {
        this(rabbitURI, exchangeName, queueName, null);
    }

    public RMQSpout(String rabbitURI, String exchangeName, String queueName, String queueSize) {
        this.rabbitURI = rabbitURI;
        this.exchangeName = exchangeName;
        this._queueName = queueName;
        if (queueSize != null) {
            QOS = Integer.parseInt(queueSize);
        }
    }

    public void open(Map conf, TopologyContext context, SpoutOutputCollector collector) {
        this.collector = collector;
        if (factory == null) {
            connect();
        }
        r = new Random();
    }

    public void connect() {
        try {
            factory = new ConnectionFactory();
            factory.setUri(rabbitURI);

            connection = factory.newConnection();
            channel = connection.createChannel();

            channel.exchangeDeclare(exchangeName, "fanout", true);
            if (QOS > 0) {
                channel.basicQos(QOS);
            }

            // TODO: Setup message-ttl so we don't gum up the works if things get bad.
            //         Map<String, Object> args = new HashMap<String, Object>();
            //         args.put("x-message-ttl", 60000);

            String queueName;
            if (_queueName != null) {
                queueName = _queueName;
                channel.queueDeclare(queueName, true, false, false, null);
            } else {
                queueName = channel.queueDeclare().getQueue();
            }

            channel.queueBind(queueName, exchangeName, "");

            consumer = new QueueingConsumer(channel);
            channel.basicConsume(queueName, false, consumer);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException("Failed to setup reader", e);
        }
    }

    public void activate() {
        if (factory == null) {
            connect();
        }
    }

    public void disconnect() {
        if (factory != null) {
            try {
                consumer = null;
                channel.close();
                channel = null;
                connection.close();
                connection = null;
                factory = null;
            } catch (IOException e) {
                e.printStackTrace();
                throw new RuntimeException(e);
            }
        }
    }

    public void deactivate() {
        disconnect();
    }

    public void nextTuple() {
        try {
            Delivery d = consumer.nextDelivery(0);
            if (d != null) {
                long tag = d.getEnvelope().getDeliveryTag();
                int an_id = r.nextInt();
                out_id.put(an_id, tag);
                collector.emit(new Values(d.getBody()), an_id);
            }
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }

    @Override
    public void ack(Object msgId) {
        try {
            Integer an_id = (Integer) msgId;
            channel.basicAck(out_id.remove(an_id), false);
        } catch (IOException e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }

    @Override
    public void fail(Object msgId) {
        try {
            Integer an_id = (Integer) msgId;
            channel.basicNack(out_id.remove(an_id), false, false);
        } catch (IOException e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }

    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        declarer.declare(new Fields("msg"));
    }
}