Java tutorial
/* * * 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.airavata.messaging.core.impl; import com.rabbitmq.client.*; import org.apache.airavata.common.exception.AiravataException; import org.apache.airavata.common.exception.ApplicationSettingsException; import org.apache.airavata.common.utils.AiravataUtils; import org.apache.airavata.common.utils.ServerSettings; import org.apache.airavata.common.utils.ThriftUtils; import org.apache.airavata.messaging.core.Consumer; import org.apache.airavata.messaging.core.MessageContext; import org.apache.airavata.messaging.core.MessageHandler; import org.apache.airavata.messaging.core.MessagingConstants; import org.apache.airavata.model.messaging.event.*; import org.apache.thrift.TBase; import org.apache.thrift.TException; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class RabbitMQConsumer implements Consumer { private static Logger log = LoggerFactory.getLogger(RabbitMQConsumer.class); private String exchangeName; private String url; private Connection connection; private Channel channel; private Map<String, QueueDetails> queueDetailsMap = new HashMap<String, QueueDetails>(); public RabbitMQConsumer() throws AiravataException { try { url = ServerSettings.getSetting(MessagingConstants.RABBITMQ_BROKER_URL); exchangeName = ServerSettings.getSetting(MessagingConstants.RABBITMQ_EXCHANGE_NAME); createConnection(); } catch (ApplicationSettingsException e) { String message = "Failed to get read the required properties from airavata to initialize rabbitmq"; log.error(message, e); throw new AiravataException(message, e); } } public RabbitMQConsumer(String brokerUrl, String exchangeName) throws AiravataException { this.exchangeName = exchangeName; this.url = brokerUrl; createConnection(); } private void createConnection() throws AiravataException { try { ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setUri(url); connection = connectionFactory.newConnection(); connection.addShutdownListener(new ShutdownListener() { public void shutdownCompleted(ShutdownSignalException cause) { } }); log.info("connected to rabbitmq: " + connection + " for " + exchangeName); channel = connection.createChannel(); channel.exchangeDeclare(exchangeName, "topic", false); } catch (Exception e) { String msg = "could not open channel for exchange " + exchangeName; log.error(msg); throw new AiravataException(msg, e); } } public String listen(final MessageHandler handler) throws AiravataException { try { Map<String, Object> props = handler.getProperties(); final Object routing = props.get(MessagingConstants.RABBIT_ROUTING_KEY); if (routing == null) { throw new IllegalArgumentException("The routing key must be present"); } List<String> keys = new ArrayList<String>(); if (routing instanceof List) { for (Object o : (List) routing) { keys.add(o.toString()); } } else if (routing instanceof String) { keys.add((String) routing); } String queueName = (String) props.get(MessagingConstants.RABBIT_QUEUE); String consumerTag = (String) props.get(MessagingConstants.RABBIT_CONSUMER_TAG); if (queueName == null) { if (!channel.isOpen()) { channel = connection.createChannel(); channel.exchangeDeclare(exchangeName, "topic", false); } queueName = channel.queueDeclare().getQueue(); } else { channel.queueDeclare(queueName, true, false, false, null); } final String id = getId(keys, queueName); if (queueDetailsMap.containsKey(id)) { throw new IllegalStateException("This subscriber is already defined for this Consumer, " + "cannot define the same subscriber twice"); } if (consumerTag == null) { consumerTag = "default"; } // bind all the routing keys for (String routingKey : keys) { channel.queueBind(queueName, exchangeName, routingKey); } channel.basicConsume(queueName, true, consumerTag, new DefaultConsumer(channel) { @Override public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) { Message message = new Message(); try { ThriftUtils.createThriftFromBytes(body, message); TBase event = null; String gatewayId = null; if (message.getMessageType().equals(MessageType.EXPERIMENT)) { ExperimentStatusChangeEvent experimentStatusChangeEvent = new ExperimentStatusChangeEvent(); ThriftUtils.createThriftFromBytes(message.getEvent(), experimentStatusChangeEvent); log.debug(" Message Received with message id '" + message.getMessageId() + "' and with message type '" + message.getMessageType() + "' with status " + experimentStatusChangeEvent.getState()); event = experimentStatusChangeEvent; gatewayId = experimentStatusChangeEvent.getGatewayId(); } else if (message.getMessageType().equals(MessageType.WORKFLOWNODE)) { WorkflowNodeStatusChangeEvent wfnStatusChangeEvent = new WorkflowNodeStatusChangeEvent(); ThriftUtils.createThriftFromBytes(message.getEvent(), wfnStatusChangeEvent); log.debug(" Message Received with message id '" + message.getMessageId() + "' and with message type '" + message.getMessageType() + "' with status " + wfnStatusChangeEvent.getState()); event = wfnStatusChangeEvent; gatewayId = wfnStatusChangeEvent.getWorkflowNodeIdentity().getGatewayId(); } else if (message.getMessageType().equals(MessageType.TASK)) { TaskStatusChangeEvent taskStatusChangeEvent = new TaskStatusChangeEvent(); ThriftUtils.createThriftFromBytes(message.getEvent(), taskStatusChangeEvent); log.debug(" Message Received with message id '" + message.getMessageId() + "' and with message type '" + message.getMessageType() + "' with status " + taskStatusChangeEvent.getState()); event = taskStatusChangeEvent; gatewayId = taskStatusChangeEvent.getTaskIdentity().getGatewayId(); } else if (message.getMessageType().equals(MessageType.JOB)) { JobStatusChangeEvent jobStatusChangeEvent = new JobStatusChangeEvent(); ThriftUtils.createThriftFromBytes(message.getEvent(), jobStatusChangeEvent); log.debug(" Message Received with message id '" + message.getMessageId() + "' and with message type '" + message.getMessageType() + "' with status " + jobStatusChangeEvent.getState()); event = jobStatusChangeEvent; gatewayId = jobStatusChangeEvent.getJobIdentity().getGatewayId(); } MessageContext messageContext = new MessageContext(event, message.getMessageType(), message.getMessageId(), gatewayId); messageContext.setUpdatedTime(AiravataUtils.getTime(message.getUpdatedTime())); handler.onMessage(messageContext); } catch (TException e) { String msg = "Failed to de-serialize the thrift message, from routing keys and queueName " + id; log.warn(msg, e); } } }); // save the name for deleting the queue queueDetailsMap.put(id, new QueueDetails(queueName, keys)); return id; } catch (Exception e) { String msg = "could not open channel for exchange " + exchangeName; log.error(msg); throw new AiravataException(msg, e); } } public void stopListen(final String id) throws AiravataException { QueueDetails details = queueDetailsMap.get(id); if (details != null) { try { for (String key : details.getRoutingKeys()) { channel.queueUnbind(details.getQueueName(), exchangeName, key); } channel.queueDelete(details.getQueueName(), true, true); } catch (IOException e) { String msg = "could not un-bind queue: " + details.getQueueName() + " for exchange " + exchangeName; log.error(msg); throw new AiravataException(msg, e); } } } /** * Private class for holding some information about the consumers registered */ private class QueueDetails { String queueName; List<String> routingKeys; private QueueDetails(String queueName, List<String> routingKeys) { this.queueName = queueName; this.routingKeys = routingKeys; } public String getQueueName() { return queueName; } public List<String> getRoutingKeys() { return routingKeys; } } private String getId(List<String> routingKeys, String queueName) { String id = ""; for (String key : routingKeys) { id = id + "_" + key; } return id + "_" + queueName; } public void close() { if (connection != null) { try { connection.close(); } catch (IOException ignore) { } } } }