/*
* Copyright 2012-2015, the original author or 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 com.flipkart.phantom.runtime.impl.server.netty.handler.command;
import com.flipkart.phantom.event.ServiceProxyEvent;
import com.flipkart.phantom.event.ServiceProxyEventProducer;
import com.flipkart.phantom.task.impl.TaskHandlerExecutor;
import com.flipkart.phantom.task.impl.TaskHandlerExecutorRepository;
import com.flipkart.phantom.task.impl.TaskRequestWrapper;
import org.jboss.netty.channel.*;
import org.jboss.netty.channel.group.ChannelGroup;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* <code>AsyncCommandProcessingChannelHandler</code> is similar to @link{CommandProcessingChannelHandler} except it executes the
* commands asynchronously.
*
* @author devashish.shankar
* @version 1.0, 10 Jun 2013
*/
public class AsyncCommandProcessingChannelHandler extends SimpleChannelUpstreamHandler {
/** Logger for this class*/
private static final Logger LOGGER = LoggerFactory.getLogger(AsyncCommandProcessingChannelHandler.class);
/** The param key for pool name */
public static final String POOL_PARAM = "pool";
/** The default channel group*/
private ChannelGroup defaultChannelGroup;
/** The TaskRepository to lookup TaskHandlerExecutors from */
private TaskHandlerExecutorRepository repository;
/** The publisher used to broadcast events to Service Proxy Subscribers */
private ServiceProxyEventProducer eventProducer;
/** Event Type for publishing all events which are generated here */
private final static String ASYNC_COMMAND_HANDLER = "ASYNC_COMMAND_HANDLER";
/**
* Overriden superclass method. Adds the newly created Channel to the default channel group and calls the super class {@link #channelOpen(org.jboss.netty.channel.ChannelHandlerContext, org.jboss.netty.channel.ChannelStateEvent)} method
* @see org.jboss.netty.channel.SimpleChannelUpstreamHandler#channelOpen(org.jboss.netty.channel.ChannelHandlerContext, org.jboss.netty.channel.ChannelStateEvent)
*/
public void channelOpen(ChannelHandlerContext ctx, ChannelStateEvent event) throws Exception {
super.channelOpen(ctx, event);
this.defaultChannelGroup.add(event.getChannel());
}
/**
* Interface method implementation. Reads and processes commands sent to the service proxy. Expects data in the command protocol defined in the class summary.
* Discards commands that do not have a {@link com.flipkart.phantom.task.impl.TaskHandler} mapping.
* @see org.jboss.netty.channel.SimpleChannelUpstreamHandler#handleUpstream(org.jboss.netty.channel.ChannelHandlerContext, org.jboss.netty.channel.ChannelEvent)
*/
public void handleUpstream(ChannelHandlerContext ctx, ChannelEvent event) throws Exception {
long receiveTime = System.currentTimeMillis();
if (MessageEvent.class.isAssignableFrom(event.getClass())) {
CommandInterpreter commandInterpreter = new CommandInterpreter();
CommandInterpreter.ProxyCommand readCommand = commandInterpreter.readCommand((MessageEvent) event);
LOGGER.debug("Read Command : " + readCommand);
String pool = readCommand.getCommandParams().get("pool");
String commandName = readCommand.getCommand();
String poolName;
if (pool != null) {
poolName = pool;
} else {
poolName = commandName;
}
/** Prepare the request Wrapper */
TaskRequestWrapper taskRequestWrapper = new TaskRequestWrapper();
taskRequestWrapper.setData(readCommand.getCommandData());
taskRequestWrapper.setParams(readCommand.getCommandParams());
TaskHandlerExecutor executor = (TaskHandlerExecutor) this.repository.getExecutor(commandName, poolName, taskRequestWrapper);
/** Execute */
try {
this.repository.executeAsyncCommand(commandName, poolName, taskRequestWrapper);
LOGGER.debug("Successfully started execution for async command " + commandName);
} catch (Exception e) {
LOGGER.error("Error asynchronously executing the command", e);
} finally {
if (eventProducer != null) {
// Publishes event both in case of success and failure.
final String requestID = readCommand.getCommandParams().get("requestID");
ServiceProxyEvent.Builder eventBuilder;
if (executor == null)
eventBuilder = new ServiceProxyEvent.Builder(readCommand.getCommand(), ASYNC_COMMAND_HANDLER).withEventSource(getClass().getName());
else
eventBuilder = executor.getEventBuilder().withCommandData(executor).withEventSource(executor.getClass().getName());
eventBuilder.withRequestId(requestID).withRequestReceiveTime(receiveTime);
eventProducer.publishEvent(eventBuilder.build());
} else
LOGGER.debug("eventProducer not set, not publishing event");
}
}
super.handleUpstream(ctx, event);
}
/**
* Interface method implementation. Closes the underlying channel after logging a warning message
* @see org.jboss.netty.channel.SimpleChannelHandler#exceptionCaught(org.jboss.netty.channel.ChannelHandlerContext, org.jboss.netty.channel.ExceptionEvent)
*/
public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent event) throws Exception {
LOGGER.warn("Exception {} thrown on Channel {}. Disconnect initiated",event,event.getChannel());
event.getChannel().close();
}
/** Start Getter/Setter methods */
public ChannelGroup getDefaultChannelGroup() {
return this.defaultChannelGroup;
}
public void setDefaultChannelGroup(ChannelGroup defaultChannelGroup) {
this.defaultChannelGroup = defaultChannelGroup;
}
public TaskHandlerExecutorRepository getRepository() {
return this.repository;
}
public void setRepository(TaskHandlerExecutorRepository repository) {
this.repository = repository;
}
public void setEventProducer(final ServiceProxyEventProducer eventProducer) {
this.eventProducer = eventProducer;
}
/** End Getter/Setter methods */
}