Java tutorial
/* * Copyright 2013 - 2017 The Original Authors * * 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 org.elasticsoftware.elasticactors.rabbitmq; import com.rabbitmq.client.*; import net.jodah.lyra.event.ChannelListener; import org.apache.logging.log4j.LogManager; import org.apache.logging.log4j.Logger; import org.elasticsoftware.elasticactors.MessageDeliveryException; import org.elasticsoftware.elasticactors.messaging.InternalMessage; import org.elasticsoftware.elasticactors.messaging.MessageHandler; import org.elasticsoftware.elasticactors.messaging.MessageHandlerEventListener; import org.elasticsoftware.elasticactors.messaging.MessageQueue; import org.elasticsoftware.elasticactors.serialization.internal.InternalMessageDeserializer; import org.elasticsoftware.elasticactors.util.concurrent.ThreadBoundExecutor; import org.elasticsoftware.elasticactors.util.concurrent.ThreadBoundRunnable; import java.io.IOException; import java.util.concurrent.CountDownLatch; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicBoolean; import static java.lang.String.format; /** * @author Joost van de Wijgerd */ public final class LocalMessageQueue extends DefaultConsumer implements MessageQueue, ChannelListener { private static final Logger logger = LogManager.getLogger(LocalMessageQueue.class); private final Channel consumerChannel; private final Channel producerChannel; private final String exchangeName; private final String queueName; private final MessageHandler messageHandler; private final TransientAck transientAck = new TransientAck(); private final ThreadBoundExecutor queueExecutor; private final CountDownLatch destroyLatch = new CountDownLatch(1); private final InternalMessageDeserializer internalMessageDeserializer; private final AtomicBoolean recovering = new AtomicBoolean(false); private final ChannelListenerRegistry channelListenerRegistry; private final MessageAcker messageAcker; public LocalMessageQueue(ThreadBoundExecutor queueExecutor, ChannelListenerRegistry channelListenerRegistry, Channel consumerChannel, Channel producerChannel, String exchangeName, String queueName, MessageHandler messageHandler, InternalMessageDeserializer internalMessageDeserializer, MessageAcker messageAcker) { super(consumerChannel); this.queueExecutor = queueExecutor; this.consumerChannel = consumerChannel; this.producerChannel = producerChannel; this.exchangeName = exchangeName; this.queueName = queueName; this.messageHandler = messageHandler; this.internalMessageDeserializer = internalMessageDeserializer; this.messageAcker = messageAcker; this.channelListenerRegistry = channelListenerRegistry; this.channelListenerRegistry.addChannelListener(this.producerChannel, this); } @Override public boolean offer(final InternalMessage message) { // see if we are recovering first if (this.recovering.get()) { throw new MessageDeliveryException("MessagingService is recovering", true); } if (!message.isDurable()) { // execute on a separate (thread bound) executor queueExecutor .execute(new InternalMessageHandler(queueName, message, messageHandler, transientAck, logger)); return true; } else { try { final AMQP.BasicProperties props = createProps(message); producerChannel.basicPublish(exchangeName, queueName, false, false, props, message.toByteArray()); return true; } catch (IOException e) { throw new MessageDeliveryException("IOException while publishing message", e, false); } catch (AlreadyClosedException e) { this.recovering.set(true); throw new MessageDeliveryException("MessagingService is recovering", true); } } } private AMQP.BasicProperties createProps(InternalMessage message) { if (message.getTimeout() < 0) { return message.isDurable() ? MessageProperties.PERSISTENT_BASIC : MessageProperties.BASIC; } else { if (message.isDurable()) { return new AMQP.BasicProperties.Builder().contentType("application/octet-stream").deliveryMode(2) .priority(0).expiration(String.valueOf(message.getTimeout())).build(); } else { return new AMQP.BasicProperties.Builder().contentType("application/octet-stream").deliveryMode(1) .priority(0).expiration(String.valueOf(message.getTimeout())).build(); } } } @Override public boolean add(InternalMessage message) { return offer(message); } @Override public InternalMessage poll() { return null; } @Override public String getName() { return queueName; } @Override public void initialize() throws Exception { consumerChannel.basicConsume(queueName, false, this); } @Override public void destroy() { try { consumerChannel.basicCancel(getConsumerTag()); destroyLatch.await(4, TimeUnit.SECONDS); } catch (IOException e) { logger.error("IOException while cancelling consumer", e); } catch (InterruptedException e) { // ignore } finally { this.channelListenerRegistry.removeChannelListener(this.producerChannel, this); } } @Override public void handleCancelOk(String consumerTag) { destroyLatch.countDown(); } @Override public void handleCancel(String consumerTag) throws IOException { // we were cancelled by an outside force, should not happen. treat as an error logger.error(format("Unexpectedly cancelled: consumerTag = %s", consumerTag)); } @Override public void handleShutdownSignal(String consumerTag, ShutdownSignalException sig) { // @todo: some kind of higher level error handling } @Override public void handleRecoverOk(String consumerTag) { } @Override public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException { try { messageAcker.deliver(envelope.getDeliveryTag()); // execute on seperate (thread bound) executor queueExecutor.execute(new RabbitMQMessageHandler(queueName, body, internalMessageDeserializer, messageHandler, new RabbitMQAck(envelope), logger)); } catch (Exception e) { logger.error( "Unexpected Exception on handleDelivery.. Acking the message so it will not clog up the system", e); messageAcker.ack(envelope.getDeliveryTag()); } } @Override public void onCreate(Channel channel) { // ignore } @Override public void onCreateFailure(Throwable failure) { // ignore } @Override public void onRecovery(Channel channel) { } @Override public void onRecoveryStarted(Channel channel) { } @Override public void onRecoveryCompleted(Channel channel) { // reset the recovery flag if (this.recovering.compareAndSet(true, false)) { logger.info("RabbitMQ Channel recovered"); } } @Override public void onRecoveryFailure(Channel channel, Throwable failure) { // log an error logger.error("RabbitMQ Channel recovery failed"); } private static final class RabbitMQMessageHandler implements ThreadBoundRunnable<String> { private final String queueName; private final InternalMessageDeserializer internalMessageDeserializer; private final byte[] body; private final MessageHandler messageHandler; private final MessageHandlerEventListener listener; private final Logger logger; private final long startTime; private RabbitMQMessageHandler(String queueName, byte[] body, InternalMessageDeserializer internalMessageDeserializer, MessageHandler messageHandler, MessageHandlerEventListener listener, Logger logger) { this.queueName = queueName; this.internalMessageDeserializer = internalMessageDeserializer; this.body = body; this.messageHandler = messageHandler; this.listener = listener; this.logger = logger; this.startTime = System.currentTimeMillis(); } @Override public String getKey() { return queueName; } @Override public void run() { InternalMessage message = null; try { // get the body data message = internalMessageDeserializer.deserialize(body); messageHandler.handleMessage(message, listener); } catch (Exception e) { logger.error("Unexpected exception on #handleMessage", e); } finally { if (logger.isTraceEnabled()) { long endTime = System.currentTimeMillis(); if (message != null) { logger.trace(format( "(rabbit) Message of type [%s] with id [%s] took %d msecs to execute on queue [%s]", message.getPayloadClass(), message.getId().toString(), endTime - startTime, queueName)); } } } } } private final class RabbitMQAck implements MessageHandlerEventListener { private final Envelope envelope; //private final InternalMessage message; private RabbitMQAck(Envelope envelope) { this.envelope = envelope; } @Override public void onError(final InternalMessage message, final Throwable exception) { onDone(message); } @Override public void onDone(final InternalMessage message) { messageAcker.ack(envelope.getDeliveryTag()); } } private static final class InternalMessageHandler implements ThreadBoundRunnable<String> { private final String queueName; private final InternalMessage message; private final MessageHandler messageHandler; private final MessageHandlerEventListener listener; private final Logger logger; private final long startTime; private InternalMessageHandler(String queueName, InternalMessage message, MessageHandler messageHandler, MessageHandlerEventListener listener, Logger logger) { this.queueName = queueName; this.message = message; this.messageHandler = messageHandler; this.listener = listener; this.logger = logger; this.startTime = System.currentTimeMillis(); } @Override public String getKey() { return queueName; } @Override public void run() { try { messageHandler.handleMessage(message, listener); } catch (Exception e) { logger.error("Unexpected exception on #handleMessage", e); } finally { if (logger.isTraceEnabled()) { long endTime = System.currentTimeMillis(); logger.trace(format( "(local) Message of type [%s] with id [%s] took %d msecs to execute on queue [%s]", message.getPayloadClass(), message.getId().toString(), endTime - startTime, queueName)); } } } } private final class TransientAck implements MessageHandlerEventListener { @Override public void onError(InternalMessage message, Throwable exception) { logger.error(format("Error handling transient message, payloadClass [%s]", message.getPayloadClass()), exception); } @Override public void onDone(InternalMessage message) { // do nothing } } }