SendDefaultImpl method in which:
for (; times < timesTotal; times++) {
String lastBrokerName = null == mq ? null : mq.getBrokerName();
MessageQueue mqSelected = this.selectOneMessageQueue(topicPublishInfo, lastBrokerName);
if (mqSelected != null) {
mq = mqSelected;
brokersSent[times] = mq.getBrokerName();
try {
beginTimestampPrev = System.currentTimeMillis();
long costTime = beginTimestampPrev - beginTimestampFirst;
if (timeout < costTime) {
callTimeout = true;
break;
}
sendResult = this.sendKernelImpl(msg, mq, communicationMode, sendCallback, topicPublishInfo, timeout - costTime);
endTimestamp = System.currentTimeMillis();
this.updateFaultItem(mq.getBrokerName(), endTimestamp - beginTimestampPrev, false);
switch (communicationMode) {
case ASYNC:
return null;
case ONEWAY:
return null;
case SYNC:
if (sendResult.getSendStatus() != SendStatus.SEND_OK) {
if (this.defaultMQProducer.isRetryAnotherBrokerWhenNotStoreOK()) {
continue;
}
}
return sendResult;
default:
break;
}
} catch (RemotingException e) {
endTimestamp = System.currentTimeMillis();
this.updateFaultItem(mq.getBrokerName(), endTimestamp - beginTimestampPrev, true);
log.warn(String.format("sendKernelImpl exception, resend at once, InvokeID: %s, RT: %sms, Broker: %s", invokeID, endTimestamp - beginTimestampPrev, mq), e);
log.warn(msg.toString());
exception = e;
continue;
} catch (MQClientException e) {
endTimestamp = System.currentTimeMillis();
this.updateFaultItem(mq.getBrokerName(), endTimestamp - beginTimestampPrev, true);
log.warn(String.format("sendKernelImpl exception, resend at once, InvokeID: %s, RT: %sms, Broker: %s", invokeID, endTimestamp - beginTimestampPrev, mq), e);
log.warn(msg.toString());
exception = e;
continue;
If it is synchronized, it must be sent successfully, it must also know that success return is ok, otherwise continue to retry.
If you are oneway, asynchronous, then direct return null out, then how do asynchronous retry?
The above code is the core function is to send sendKernelImpl
SendResult sendResult = null;
switch (communicationMode) {
case ASYNC:
Message tmpMessage = msg;
if (msgBodyCompressed) {
//If msg body was compressed, msgbody should be reset using prevBody.
//Clone new message using commpressed message body and recover origin massage.
//Fix bug:https://github.com/apache/rocketmq-externals/issues/66
tmpMessage = MessageAccessor.cloneMessage(msg);
msg.setBody(prevBody);
}
long costTimeAsync = System.currentTimeMillis() - beginStartTime;
if (timeout < costTimeAsync) {
throw new RemotingTooMuchRequestException("sendKernelImpl call timeout");
}
sendResult = this.mQClientFactory.getMQClientAPIImpl().sendMessage(
brokerAddr,
mq.getBrokerName(),
tmpMessage,
requestHeader,
timeout - costTimeAsync,
communicationMode,
sendCallback,
topicPublishInfo,
this.mQClientFactory,
this.defaultMQProducer.getRetryTimesWhenSendAsyncFailed(),
context,
this);
break;
case ONEWAY:
case SYNC:
long costTimeSync = System.currentTimeMillis() - beginStartTime;
if (timeout < costTimeSync) {
throw new RemotingTooMuchRequestException("sendKernelImpl call timeout");
}
sendResult = this.mQClientFactory.getMQClientAPIImpl().sendMessage(
brokerAddr,
mq.getBrokerName(),
msg,
requestHeader,
timeout - costTimeSync,
communicationMode,
context,
this);
break;
default:
assert false;
break;
}
Can see that for asynchronous and non-asynchronous mode, sendMessage incoming method is not the same, in asynchronous mode, into a this.defaultMQProducer.getRetryTimesWhenSendAsyncFailed ()
Here I will not speak asynchronous try again. rocketmq for the number of threads and asynchronous send one-way messages the same time is constrained, because unlike synchronous as were blocked to prevent sending too many take up too many resources.
The particular constraint is achieved by semaphore:
public NettyRemotingAbstract(final int permitsOneway, final int permitsAsync) {
this.semaphoreOneway = new Semaphore(permitsOneway, true);
this.semaphoreAsync = new Semaphore(permitsAsync, true);
}
For oneway, this.semaphoreOneway.tryAcquire success means that threads compete for resources to get, go writeandFlush later, as long as no abnormalities, then that message has been sent, do not need to check anything.
public void invokeOnewayImpl(final Channel channel, final RemotingCommand request, final long timeoutMillis)
throws InterruptedException, RemotingTooMuchRequestException, RemotingTimeoutException, RemotingSendRequestException {
request.markOnewayRPC();
boolean acquired = this.semaphoreOneway.tryAcquire(timeoutMillis, TimeUnit.MILLISECONDS);
if (acquired) {
final SemaphoreReleaseOnlyOnce once = new SemaphoreReleaseOnlyOnce(this.semaphoreOneway);
try {
channel.writeAndFlush(request).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture f) throws Exception {
once.release();
if (!f.isSuccess()) {
log.warn("send a request command to channel <" + channel.remoteAddress() + "> failed.");
}
}
});
} catch (Exception e) {
once.release();
log.warn("write send a request command to channel <" + channel.remoteAddress() + "> failed.");
throw new RemotingSendRequestException(RemotingHelper.parseChannelRemoteAddr(channel), e);
}
} else {
if (timeoutMillis <= 0) {
throw new RemotingTooMuchRequestException("invokeOnewayImpl invoke too fast");
} else {
String info = String.format(
"invokeOnewayImpl tryAcquire semaphore timeout, %dms, waiting thread nums: %d semaphoreAsyncValue: %d",
timeoutMillis,
this.semaphoreOneway.getQueueLength(),
this.semaphoreOneway.availablePermits()
);
log.warn(info);
throw new RemotingTimeoutException(info);
}
}
}
For synchronous call for:
public RemotingCommand invokeSyncImpl(final Channel channel, final RemotingCommand request,
final long timeoutMillis)
throws InterruptedException, RemotingSendRequestException, RemotingTimeoutException {
final int opaque = request.getOpaque();
try {
final ResponseFuture responseFuture = new ResponseFuture(channel, opaque, timeoutMillis, null, null);
this.responseTable.put(opaque, responseFuture);
final SocketAddress addr = channel.remoteAddress();
channel.writeAndFlush(request).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture f) throws Exception {
if (f.isSuccess()) {
responseFuture.setSendRequestOK(true);
return;
} else {
responseFuture.setSendRequestOK(false);
}
responseTable.remove(opaque);
responseFuture.setCause(f.cause());
responseFuture.putResponse(null);
log.warn("send a request command to channel <" + addr + "> failed.");
}
});
RemotingCommand responseCommand = responseFuture.waitResponse(timeoutMillis);
if (null == responseCommand) {
if (responseFuture.isSendRequestOK()) {
throw new RemotingTimeoutException(RemotingHelper.parseSocketAddressAddr(addr), timeoutMillis,
responseFuture.getCause());
} else {
throw new RemotingSendRequestException(RemotingHelper.parseSocketAddressAddr(addr), responseFuture.getCause());
}
}
return responseCommand;
} finally {
this.responseTable.remove(opaque);
}
}
Similarly with dubbo, construct a map of the future members responseTable, sent out the request, the thread is blocked waiting for the use of the future, waiting for Shane? Since it is a synchronous request, it must be waiting for response. Netty-based communication, then, response generally in the other thread, so back up here, the following is ResponseFuture responseFuture blocking and wake Code
public RemotingCommand waitResponse(final long timeoutMillis) throws InterruptedException {
this.countDownLatch.await(timeoutMillis, TimeUnit.MILLISECONDS);
return this.responseCommand;
}
public void putResponse(final RemotingCommand responseCommand) {
this.responseCommand = responseCommand;
this.countDownLatch.countDown();
}
This putResponse or is sent when the above code has failed, then quickly put into a null, otherwise it is in processResponseCommand waiting to receive a response. After the response is to get a synchronization request to complete the process.
We know that asynchronous request, sent after sending thread can be returned directly.
Asynchronous message processing is here:
private void sendMessageAsync(
final String addr,
final String brokerName,
final Message msg,
final long timeoutMillis,
final RemotingCommand request,
final SendCallback sendCallback,
final TopicPublishInfo topicPublishInfo,
final MQClientInstance instance,
final int retryTimesWhenSendFailed,
final AtomicInteger times,
final SendMessageContext context,
final DefaultMQProducerImpl producer
) throws InterruptedException, RemotingException {
this.remotingClient.invokeAsync(addr, request, timeoutMillis, new InvokeCallback() {
@Override
public void operationComplete(ResponseFuture responseFuture) {
RemotingCommand response = responseFuture.getResponseCommand();
if (null == sendCallback && response != null) {
try {
SendResult sendResult = MQClientAPIImpl.this.processSendResponse(brokerName, msg, response);
if (context != null && sendResult != null) {
context.setSendResult(sendResult);
context.getProducer().executeSendMessageHookAfter(context);
}
} catch (Throwable e) {
}
producer.updateFaultItem(brokerName, System.currentTimeMillis() - responseFuture.getBeginTimestamp(), false);
return;
}
if (response != null) {
try {
SendResult sendResult = MQClientAPIImpl.this.processSendResponse(brokerName, msg, response);
assert sendResult != null;
if (context != null) {
context.setSendResult(sendResult);
context.getProducer().executeSendMessageHookAfter(context);
}
try {
sendCallback.onSuccess(sendResult);
} catch (Throwable e) {
}
producer.updateFaultItem(brokerName, System.currentTimeMillis() - responseFuture.getBeginTimestamp(), false);
} catch (Exception e) {
producer.updateFaultItem(brokerName, System.currentTimeMillis() - responseFuture.getBeginTimestamp(), true);
onExceptionImpl(brokerName, msg, 0L, request, sendCallback, topicPublishInfo, instance,
retryTimesWhenSendFailed, times, e, context, false, producer);
}
} else {
producer.updateFaultItem(brokerName, System.currentTimeMillis() - responseFuture.getBeginTimestamp(), true);
if (!responseFuture.isSendRequestOK()) {
MQClientException ex = new MQClientException("send request failed", responseFuture.getCause());
onExceptionImpl(brokerName, msg, 0L, request, sendCallback, topicPublishInfo, instance,
retryTimesWhenSendFailed, times, ex, context, true, producer);
} else if (responseFuture.isTimeout()) {
MQClientException ex = new MQClientException("wait response timeout " + responseFuture.getTimeoutMillis() + "ms",
responseFuture.getCause());
onExceptionImpl(brokerName, msg, 0L, request, sendCallback, topicPublishInfo, instance,
retryTimesWhenSendFailed, times, ex, context, true, producer);
} else {
MQClientException ex = new MQClientException("unknow reseaon", responseFuture.getCause());
onExceptionImpl(brokerName, msg, 0L, request, sendCallback, topicPublishInfo, instance,
retryTimesWhenSendFailed, times, ex, context, true, producer);
}
}
}
});
}
This method is a big lump, in fact, only one sentence this.remotingClient.invokeAsync, in addition to this one, is a callback function InvokeCallback, whether this callback InvokeCallback receiving a ResponseFuture, check this future success inside the response to decide whether or not enter onExceptionImpl logic, onExceptionImpl which came back to sendMessageAsync continue to retry until the number of asynchronous run out.
Here we must note that the sender not to send asynchronous whether successful if it is an exception occurs in the asynchronous transmission, it is a direct throw an exception, so that clients perceive exception.
If it is sent without any problems, get the wrong response or a timeout, then rocketmq will automatically help you try again.
Continue in-depth this.remotingClient.invokeAsync:
public void invokeAsyncImpl(final Channel channel, final RemotingCommand request, final long timeoutMillis,
final InvokeCallback invokeCallback)
throws InterruptedException, RemotingTooMuchRequestException, RemotingTimeoutException, RemotingSendRequestException {
long beginStartTime = System.currentTimeMillis();
final int opaque = request.getOpaque();
boolean acquired = this.semaphoreAsync.tryAcquire(timeoutMillis, TimeUnit.MILLISECONDS);
if (acquired) {
final SemaphoreReleaseOnlyOnce once = new SemaphoreReleaseOnlyOnce(this.semaphoreAsync);
long costTime = System.currentTimeMillis() - beginStartTime;
if (timeoutMillis < costTime) {
once.release();
throw new RemotingTimeoutException("invokeAsyncImpl call timeout");
}
final ResponseFuture responseFuture = new ResponseFuture(channel, opaque, timeoutMillis - costTime, invokeCallback, once);
this.responseTable.put(opaque, responseFuture);
try {
channel.writeAndFlush(request).addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture f) throws Exception {
if (f.isSuccess()) {
responseFuture.setSendRequestOK(true);
return;
}
requestFail(opaque);
log.warn("send a request command to channel <{}> failed.", RemotingHelper.parseChannelRemoteAddr(channel));
}
});
} catch (Exception e) {
responseFuture.release();
log.warn("send a request command to channel <" + RemotingHelper.parseChannelRemoteAddr(channel) + "> Exception", e);
throw new RemotingSendRequestException(RemotingHelper.parseChannelRemoteAddr(channel), e);
}
}
}
This with the above one-way, synchronous calls are similarities, check the semaphore can get, construct a future object into opaque as key to the map while the top InvokeCallback also into the future, As mentioned above, the retry is implemented in InvokeCallback asynchronous call, then InvokeCallback eventually be called by the future.
In the above we just did send a message to future include retry InvokeCallback placed in the map, this map is spent Shashi Hou it?
1 When sending a direct failure is called requestFail (opaque)
private void requestFail(final int opaque) {
ResponseFuture responseFuture = responseTable.remove(opaque);
if (responseFuture != null) {
responseFuture.setSendRequestOK(false);
responseFuture.putResponse(null);
try {
executeInvokeCallback(responseFuture);
} catch (Throwable e) {
log.warn("execute callback in requestFail, and callback throw", e);
} finally {
responseFuture.release();
}
}
}
2 received the message response in the future:
public void processResponseCommand(ChannelHandlerContext ctx, RemotingCommand cmd) {
final int opaque = cmd.getOpaque();
final ResponseFuture responseFuture = responseTable.get(opaque);
if (responseFuture != null) {
responseFuture.setResponseCommand(cmd);
responseTable.remove(opaque);
if (responseFuture.getInvokeCallback() != null) {
executeInvokeCallback(responseFuture);
} else {
responseFuture.putResponse(cmd);
responseFuture.release();
}
} else {
log.warn("receive response, but not matched any request, " + RemotingHelper.parseChannelRemoteAddr(ctx.channel()));
log.warn(cmd.toString());
}
}
Like with synchronous call, but one more than the synchronous call timeout scene. Sync Timeout can get a timeout scene in thread blocking, asynchronous, then it must rely on a background thread check:
public void scanResponseTable() {
final List<ResponseFuture> rfList = new LinkedList<ResponseFuture>();
Iterator<Entry<Integer, ResponseFuture>> it = this.responseTable.entrySet().iterator();
while (it.hasNext()) {
Entry<Integer, ResponseFuture> next = it.next();
ResponseFuture rep = next.getValue();
if ((rep.getBeginTimestamp() + rep.getTimeoutMillis() + 1000) <= System.currentTimeMillis()) {
rep.release();
it.remove();
rfList.add(rep);
log.warn("remove timeout request, " + rep);
}
}
for (ResponseFuture rf : rfList) {
try {
executeInvokeCallback(rf);
} catch (Throwable e) {
log.warn("scanResponseTable, operationComplete Exception", e);
}
}
}