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com.disney.groovity.util.AsyncChannel Maven / Gradle / Ivy
/*******************************************************************************
* © 2018 Disney | ABC Television Group
*
* Licensed under the Apache License, Version 2.0 (the "Apache License")
* with the following modification; you may not use this file except in
* compliance with the Apache License and the following modification to it:
* Section 6. Trademarks. is deleted and replaced with:
*
* 6. Trademarks. This License does not grant permission to use the trade
* names, trademarks, service marks, or product names of the Licensor
* and its affiliates, except as required to comply with Section 4(c) of
* the License and to reproduce the content of the NOTICE file.
*
* You may obtain a copy of the Apache License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the Apache License with the above modification is
* distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the Apache License for the specific
* language governing permissions and limitations under the Apache License.
*******************************************************************************/
package com.disney.groovity.util;
import com.disney.groovity.GroovityConstants;
import groovy.lang.Binding;
import groovy.lang.Closure;
import java.io.Closeable;
import java.io.StringWriter;
import java.util.Collection;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.ReentrantLock;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Represents an asynchronous message queue
*
* @author Alex Vigdor
*/
public class AsyncChannel implements Closeable, GroovityConstants{
public static enum Policy{ drop, evict, block }
public static final ConcurrentHashMap> ASYNC_CHANNEL_ROUTING = new ConcurrentHashMap<>();
private static final Logger log = Logger.getLogger(AsyncChannel.class.getName());
final Object key;
final public LinkedBlockingQueue messageQueue;
final public Policy policy;
final AtomicBoolean closed = new AtomicBoolean(false);
final AtomicBoolean halted = new AtomicBoolean(false);
@SuppressWarnings("rawtypes")
final Closure handler;
@SuppressWarnings("rawtypes")
final Closure closer;
final Binding binding;
@SuppressWarnings("rawtypes")
final Map variables;
final AtomicBoolean dirty = new AtomicBoolean(false);
final ReentrantLock dirtyLock = new ReentrantLock();
final DeadlockFreeExecutor asyncChannelExecutor;
public final AsyncChannelManager asyncChannelManager;
public static final AsyncChannelAnonymousManager asyncChannelAnonymousManager =
new AsyncChannelAnonymousManager();
final CompletableFuture completionFuture = new CompletableFuture(){
public boolean cancel(boolean mayInterruptIfRunning){
if(!closed.get()){
errorCondition(new InterruptedException(), true);
}
return super.cancel(mayInterruptIfRunning);
}
public Object get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException{
try {
return super.get(timeout, unit);
} catch (InterruptedException | TimeoutException e) {
errorCondition(e, true);
throw e;
}
}
};
Thread runningThread;
Object lastResult;
Throwable error;
//we'll keep the Runnable private so nobody can call externally
final Runnable processor = new Runnable(){
/**
* To be called by messaging threads, do the work of invoking the handler on messages in the queue,
* does NOT wait for work, just handles already queued work and closes the acceptor if either the
* queue contains a shutdown signal OR the handler returns a falsy value
*
* @throws Exception
*/
@SuppressWarnings("unchecked")
@Override
public synchronized void run() {
runningThread = Thread.currentThread();
Binding oldThreadBinding = ScriptHelper.THREAD_BINDING.get();
ScriptHelper.THREAD_BINDING.set(binding);
try {
Object oldIt = variables.get("it");
try{
AsyncMessage message = null;
while(!halted.get() && (message = poll())!=null){
try{
long startTime = System.currentTimeMillis();
variables.put("it",message.payload);
lastResult = handler.call(message.payload);
long endTime = System.currentTimeMillis();
long processingTime = endTime-startTime;
if(asyncChannelManager!=null){
asyncChannelManager.updateMBeanForMessageProcessed();
asyncChannelManager.updateMBeanForMessageProcessingTime(processingTime);
}
}
finally{
message.consumed();
}
}
}
catch(Exception e){
//on unhandled error we will shut the channel and clear the queue to avoid resource leakage
errorCondition(e, false);
}
finally{
variables.put("it",oldIt);
}
if(closed.get()){
if(closer!=null){
//give handler the shutdown signal, a chance to clean resources, flush buffers, etc.
lastResult = closer.call(lastResult);
}
if(error!=null){
completionFuture.completeExceptionally(error);
}
else{
completionFuture.complete(lastResult);
}
//deregister if the MBean is not null
if(asyncChannelManager != null) {
asyncChannelManager.deRegisterChannelMBean();
}
else{
//update anonymous MBean tracking for anonymous channel closed
if(log.isLoggable(Level.FINEST)){
log.log(Level.INFO,"anonymous channel closed");
}
asyncChannelAnonymousManager.incrementNumberOfTotalChannelsClose();
}
}
} catch (Exception e) {
completionFuture.completeExceptionally(e);
log.log(Level.SEVERE, "Error processing accept queue", e);
}
finally{
runningThread=null;
if(oldThreadBinding==null){
ScriptHelper.THREAD_BINDING.remove();
}
else{
ScriptHelper.THREAD_BINDING.set(oldThreadBinding);
}
}
}
};
/**
* Returns a future that can be used to block and wait for this channel to close
* @return
*/
public Future getFuture(){
return completionFuture;
}
public Throwable getError(){
return error;
}
public Object getLastResult(){
return lastResult;
}
@SuppressWarnings("rawtypes")
private AsyncChannel(DeadlockFreeExecutor asyncChannelExecutor, Object key, int queueSize, Policy policy, Closure handler, Closure closer, Object owner, Binding binding){
this.asyncChannelExecutor = asyncChannelExecutor;
this.messageQueue = new LinkedBlockingQueue<>(queueSize>0?queueSize:Integer.MAX_VALUE);
this.policy=policy;
this.key=key;
this.handler = handler.rehydrate(this,owner, owner);
this.closer=closer !=null ? closer.rehydrate(this,owner, owner) : null;
this.binding=binding;
this.variables = binding.getVariables();
if(key!=null) {
this.asyncChannelManager = new AsyncChannelManager(this);
//register MBean
asyncChannelManager.registerChannelMBean();
}
else{
this.asyncChannelManager = null;
}
}
public Object getKey(){
return key;
}
@SuppressWarnings("rawtypes")
public static AsyncChannel open(DeadlockFreeExecutor asyncChannelExecutor, Object key, int queueSize, Policy policy, Closure handler, Closure closer, Object owner, Binding binding){
AsyncChannel channel = new AsyncChannel(asyncChannelExecutor, key, queueSize, policy, handler, closer, owner, binding);
if(key!=null){
Collection channels = ASYNC_CHANNEL_ROUTING.get(key);
if(channels==null) {
channels = ConcurrentHashMap.newKeySet();
Collection oldChannels = ASYNC_CHANNEL_ROUTING.putIfAbsent(key, channels);
if(oldChannels!=null) {
channels = oldChannels;
}
}
channels.add(channel);
}else{
//update AnonymousChannel MBean when anonymous channel is opened
asyncChannelAnonymousManager.incrementNumberOfTotalChannelsOpened();
}
return channel;
}
@Override
public void close() {
close(true,false);
}
public void close(@SuppressWarnings("rawtypes") Closure closeAfter){
try{
closeAfter.call();
close();
}
catch(Throwable th){
errorCondition(th, true);
}
}
private void close(boolean markDirty, boolean clearQueue) {
if(closed.compareAndSet(false, true)){
if(key!=null){
Collection as = ASYNC_CHANNEL_ROUTING.get(key);
if(as!=null){
as.remove(this);
if(as.isEmpty()){
ASYNC_CHANNEL_ROUTING.remove(key);
}
}
}
if(clearQueue){
AsyncMessage m;
while((m = messageQueue.poll())!=null){
m.dropped();
}
}
if(markDirty){
markDirty();
}
}
}
/**
* Close this channel and discard any remaining queued tasks. Typically invoked within an accept handler if it
* decides it no longer needs to consume any messages.
*/
public void halt(){
if(halted.compareAndSet(false, true)){
close(true,true);
}
}
private void markDirty(){
//lock to force consistency of dirty state
boolean submit = false;
dirtyLock.lock();
try{
submit = dirty.compareAndSet(false, true);
}
finally{
dirtyLock.unlock();
}
if(submit){
//schedule this acceptor for processing
asyncChannelExecutor.submit(processor);
}
}
//Poll for the head of the queue, and if the queue is clear set dirty to false
private AsyncMessage poll(){
dirtyLock.lock();
try{
AsyncMessage o = messageQueue.poll();
if(o==null){
dirty.compareAndSet(true, false);
}
return o;
}
finally{
dirtyLock.unlock();
}
}
public boolean isClosed(){
return closed.get();
}
private void errorCondition(Throwable error, boolean markDirty){
this.error=error;
log.log(Level.SEVERE, "Error in async channel", error);
this.close(markDirty,true);
if(markDirty){
Thread rt = runningThread;
if(rt!=null){
rt.interrupt();
}
}
}
private static Object unwrapMessage(Object message){
if(message instanceof Closure){
try{
@SuppressWarnings("rawtypes")
Closure c = (Closure) message;
ScriptHelper helper = ScriptHelper.get(c);
Binding bodyBinding = helper.getBinding();
Object oldOut = bodyBinding.getVariables().get(OUT);
StringWriter writer = new StringWriter();
bodyBinding.setVariable(OUT, writer);
try{
message = c.call();
}
finally{
if(oldOut!=null){
bodyBinding.setVariable(OUT, oldOut);
}
else{
bodyBinding.getVariables().remove(OUT);
}
}
String s = writer.toString();
if(s.length()>0){
message = s;
}
}
catch(Exception e){
message = e;
}
}
return message;
}
/**
* Enqueue a message for an acceptor, will only block if the queue is full and the policy allows it
*
* @param message
* @param timeout how long to wait for a spot in the queue before throwing an exception
* @param unit
* @return
* @throws InterruptedException
*/
public boolean offer(Object message, long timeout, TimeUnit unit) throws InterruptedException{
message = unwrapMessage(message);
AsyncMessage am = new AsyncMessage(message, 1, timeout, unit);
return offerAsync(am);
}
private boolean offerAsync(AsyncMessage message) throws InterruptedException{
if(!closed.get()){
Object payload = unwrapMessage(message.payload);
if(payload==null){
close(true,false);
return true;
}
if(payload instanceof Throwable){
//producer sent an exception to the channel, let's close it
errorCondition((Throwable) payload,true);
return true;
}
if(!messageQueue.offer(message)){
if(policy==Policy.drop){
message.dropped();
//update message dropped on MBean
updateMBeanForMessageDropped();
return false;
}
if(policy==Policy.evict){
while(!messageQueue.offer(message)){
AsyncMessage discard = messageQueue.poll();
if(discard!=null){
discard.dropped();
//update message evicted on MBean
updateMBeanForMessageEvicted();
}
}
}
else{
//we've come to blocking
try{
if(message.timeout>0) {
if(!messageQueue.offer(message, message.timeout, message.unit)) {
throw new InterruptedException();
}
}
else{
messageQueue.put(message);
}
}
catch (InterruptedException e) {
message.dropped();
//update message dropped on MBean
updateMBeanForMessageDropped();
//failing to offer on blocking channel is a fatal error, let's close the channel
errorCondition(e, true);
throw e;
}
}
}
if(asyncChannelManager!=null) {
asyncChannelManager.updateMBeanForMessageEnqueued();
}
markDirty();
return true;
}
//update message dropped on MBean
updateMBeanForMessageDropped();
message.dropped();
return false;
}
//helper function to update MBean Object when message is dropped
private void updateMBeanForMessageDropped(){
if(asyncChannelManager!=null) {
asyncChannelManager.updateMBeanForMessagesDropped();
}
}
//helper function to update MBean Object when message is evicted
private void updateMBeanForMessageEvicted(){
if(asyncChannelManager!=null) {
asyncChannelManager.updateMBeanForMessagesEvicted();
}
}
public boolean offer(Object message) throws InterruptedException{
return offer(message,-1,TimeUnit.SECONDS);
}
public static boolean offer(Object channelKey, Object message) throws InterruptedException{
return offer(channelKey,message,-1,TimeUnit.SECONDS);
}
public static boolean offer(Object channelKey, Object message, long timeout, TimeUnit unit) throws InterruptedException{
Collection as = ASYNC_CHANNEL_ROUTING.get(channelKey);
if(as!=null && as.size()>0){
message = unwrapMessage(message);
AsyncMessage am = new AsyncMessage(message, as.size(), timeout, unit);
boolean taken = false;
for(AsyncChannel sub: as){
taken = sub.offerAsync(am) || taken;
}
return taken;
}
return false;
}
private static class AsyncMessage{
final Object payload;
final AtomicInteger consumers;
final long timeout;
final TimeUnit unit;
public AsyncMessage(Object payload, int numConsumers, long timeout, TimeUnit unit){
this.payload=payload;
this.consumers = new AtomicInteger(numConsumers);
this.timeout=timeout;
this.unit=unit;
}
public void consumed(){
this.consumers.decrementAndGet();
}
public void dropped(){
if(this.consumers.decrementAndGet()<=0){
//consumption complete, now let's cleanup any callback channels
cleanObject(payload);
}
}
@SuppressWarnings("rawtypes")
private void cleanObject(Object o){
if(o instanceof Map){
for(Object v: ((Map)o).values()){
cleanObject(v);
}
}
if(o instanceof AsyncChannel){
AsyncChannel ac = (AsyncChannel) o;
if(!ac.isClosed()){
ac.close();
}
}
}
}
}
