/*
* 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 java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.Arrays;
import java.util.List;
import org.jboss.netty.channel.ChannelEvent;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
import org.jboss.netty.channel.group.ChannelGroup;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.util.Assert;
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.collector.EventDispatchingSpanCollector;
import com.flipkart.phantom.task.impl.interceptor.ServerRequestInterceptor;
import com.flipkart.phantom.task.spi.RequestContext;
import com.flipkart.phantom.task.spi.TaskRequestWrapper;
import com.flipkart.phantom.task.spi.TaskResult;
import com.github.kristofa.brave.Brave;
import com.github.kristofa.brave.FixedSampleRateTraceFilter;
import com.github.kristofa.brave.ServerSpan;
import com.github.kristofa.brave.ServerTracer;
import com.github.kristofa.brave.TraceFilter;
import com.google.common.base.Optional;
/**
* <code>AsyncCommandProcessingChannelHandler</code> is similar to @link{CommandProcessingChannelHandler} except it executes the
* commands asynchronously.
*
* @author devashish.shankar
* @version 1.0, 10 Jun 2013
*/
@SuppressWarnings("rawtypes")
public class AsyncCommandProcessingChannelHandler extends SimpleChannelUpstreamHandler implements InitializingBean {
/** 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";
/** Event Type for publishing all events which are generated here */
private final static String ASYNC_COMMAND_HANDLER = "ASYNC_COMMAND_HANDLER";
/** The default name of the server/service this channel handler is serving*/
private static final String DEFAULT_SERVICE_NAME = "Async Command Proxy";
/** The default value for tracing frequency. This value indicates that tracing if OFF*/
private static final TraceFilter NO_TRACING = new FixedSampleRateTraceFilter(-1);
/** Default host name and port where this ChannelHandler is available */
public static final String DEFAULT_HOST = "localhost"; // unresolved local host name
public static final int DEFAULT_PORT = -1; // no valid port really
/** The local host name value*/
private static String hostName = DEFAULT_HOST;
static {
try {
hostName = InetAddress.getLocalHost().getHostName();
} catch (UnknownHostException e) {
LOGGER.warn("Unable to resolve local host name. Will use default host name : " + DEFAULT_HOST);
}
}
/** The name for the service/server*/
private String serviceName = DEFAULT_SERVICE_NAME;
/** The port where the server for this handler is listening on*/
private int hostPort;
/** 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;
/** The request tracing frequency for this channel handler*/
private TraceFilter traceFilter = NO_TRACING;
/** The EventDispatchingSpanCollector instance used in tracing requests*/
private EventDispatchingSpanCollector eventDispatchingSpanCollector;
/**
* Interface method implementation. Checks if all mandatory properties have been set
* @see org.springframework.beans.factory.InitializingBean#afterPropertiesSet()
*/
public void afterPropertiesSet() throws Exception {
Assert.notNull(this.eventDispatchingSpanCollector, "The 'eventDispatchingSpanCollector' may not be null");
}
/**
* Overriden superclass method. Stores the host port that this handler's server is listening on
* @see org.jboss.netty.channel.SimpleChannelUpstreamHandler#channelBound(org.jboss.netty.channel.ChannelHandlerContext, org.jboss.netty.channel.ChannelStateEvent)
*/
public void channelBound(ChannelHandlerContext ctx,ChannelStateEvent event) throws Exception {
super.channelBound(ctx, event);
if (InetSocketAddress.class.isAssignableFrom(event.getValue().getClass())) {
this.hostPort = ((InetSocketAddress)event.getValue()).getPort();
}
}
/**
* 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());
}
/**
* Overridden method. 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 = (String) 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.setCommandName(commandName);
taskRequestWrapper.setData(readCommand.getCommandData());
taskRequestWrapper.setParams(readCommand.getCommandParams());
// set the service name for the request
taskRequestWrapper.setServiceName(Optional.of(this.serviceName));
// Create and process a Server request interceptor. This will initialize the server tracing
ServerRequestInterceptor<TaskRequestWrapper, TaskResult> serverRequestInterceptor = this.initializeServerTracing(taskRequestWrapper);
TaskHandlerExecutor executor = (TaskHandlerExecutor) this.repository.getExecutor(commandName, poolName, taskRequestWrapper);
/** Execute */
Optional<RuntimeException> transportError = Optional.absent();
try {
this.repository.executeAsyncCommand(commandName, poolName, taskRequestWrapper);
LOGGER.debug("Successfully started execution for async command " + commandName);
} catch (Exception e) {
RuntimeException runtimeException = new RuntimeException("Error asynchronously executing the command : " + readCommand, e);
transportError = Optional.of(runtimeException);
LOGGER.error("Error asynchronously executing the command", e); // we just log the error as it is async anyway and callee will not be able to do much
} finally {
// finally inform the server request tracer
serverRequestInterceptor.process(new TaskResult(true, TaskHandlerExecutor.ASYNC_QUEUED), transportError);
if (eventProducer != null) {
// Publishes event both in case of success and failure.
final String requestID = (String) 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();
}
/**
* Initializes server tracing for the specified request
* @param executorRequest the Http request
* @return the initialized ServerRequestInterceptor
*/
private ServerRequestInterceptor<TaskRequestWrapper, TaskResult> initializeServerTracing(TaskRequestWrapper executorRequest) {
ServerRequestInterceptor<TaskRequestWrapper, TaskResult> serverRequestInterceptor = new ServerRequestInterceptor<TaskRequestWrapper, TaskResult>();
List<TraceFilter> traceFilters = Arrays.<TraceFilter>asList(this.traceFilter);
ServerTracer serverTracer = Brave.getServerTracer(this.eventDispatchingSpanCollector, traceFilters);
serverRequestInterceptor.setEndPointSubmitter(Brave.getEndPointSubmitter());
serverRequestInterceptor.setServerTracer(serverTracer);
serverRequestInterceptor.setServiceHost(AsyncCommandProcessingChannelHandler.hostName);
serverRequestInterceptor.setServicePort(this.hostPort);
serverRequestInterceptor.setServiceName(this.serviceName);
// now process the request to initialize tracing
serverRequestInterceptor.process(executorRequest);
// set the server request context on the received request
ServerSpan serverSpan = Brave.getServerSpanThreadBinder().getCurrentServerSpan();
RequestContext serverRequestContext = new RequestContext();
serverRequestContext.setCurrentServerSpan(serverSpan);
executorRequest.setRequestContext(Optional.of(serverRequestContext));
return serverRequestInterceptor;
}
/** Start Getter/Setter methods */
public ChannelGroup getDefaultChannelGroup() {
return this.defaultChannelGroup;
}
public void setServiceName(String serviceName) {
this.serviceName = serviceName;
}
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 */
}