Overriding errorChannel configured in #MessagingGateway - spring

I have configured #MessagingGateway as below to use an error channel, which works as expected.
#MessagingGateway(errorChannel = "DefaultInboundErrorHandlerChannel")
public interface InboundMessagingGateway {
#Gateway(requestChannel = "InboundEntryChannel")
void receive(XferRes response);
}
Within the flow I am passing the object to a transformer as below:
Step 1:
#Transformer(inputChannel = "InboundEntryChannel", outputChannel = "TransmissionLogChannel")
public CassandraEntity createEntity(
org.springframework.messaging.Message<XferRes> message) throws ParseException {
XferRes response = message.getPayload();
CassandraEntity entity = new CassandraEntity();
// ... getters & setter ommitted for brevity
return entity;
}
Next, I update the entity as below:
Step 2:
#ServiceActivator(inputChannel = "TransmissionLogChannel", outputChannel="PublishChannel")
public XferRes updateCassandraEntity(
org.springframework.messaging.Message<XferRes> message) {
XferRes response = message.getPayload();
this.cassandraServiceImpl.update(response);
return response;
}
And last, I post to a Kafka topic as below:
Step 3:
#ServiceActivator(inputChannel = "PublishChannel")
public void publish(org.springframework.messaging.Message<XferRes> message){
XferRes response = message.getPayload();
publisher.post(response);
}
In case of an error I post the message to a service which publishes the error object to log ingestion:
#ServiceActivator(inputChannel="defaultInboundErrorHandlerChannel")
public void handleInvalidRequest(org.springframework.messaging.Message<MessageHandlingException> message) throws ParseException {
XferRes originalRequest = (XferRes) message.getPayload().getFailedMessage().getPayload();
this.postToErrorBoard(originalRequest)
}
If an error occurs at Step 2: in updating the DB, then also I want to invoke Step 3. A trivial way is to remove the Step 2 & make the call to update database from Step 1.
Is there any other way in Spring Integration where I can invoke Step 3 irrespective if an error occurs or not.

This technique called PublishSubscribeChannel. Since I see that you reuse a payload on the second step to send to the third step, then it is definitely a use-case for the PublishSubscribeChannel and two sequential subscribers to it.
I mean you create a PublishSubscribeChannel #Bean and those #ServiceActivators are use the name to this channel.
More info is in the Reference Manual. Pay attention to the ignoreFailures property:
/**
* Specify whether failures for one or more of the handlers should be
* ignored. By default this is <code>false</code> meaning that an Exception
* will be thrown whenever a handler fails. To override this and suppress
* Exceptions, set the value to <code>true</code>.
* #param ignoreFailures true if failures should be ignored.
*/
public void setIgnoreFailures(boolean ignoreFailures) {

Related

PublishSubscribeChannel having multiple subscribers and return value

I would like to understand how returning values work for PublishSubscribeChannel having multiple subscribers.
#Bean
public PublishSubscribeChannel channel(){
return new PublishSubscribeChannel();
}
#Bean
#ServiceActivator(inputChannel = "channel")
public MessageHandler handler1() {
//...
return handler1;
}
#Bean
#ServiceActivator(inputChannel = "channel")
public MessageHandler handler2() {
//...
return handler2;
}
#Bean
#ServiceActivator(inputChannel = "channel")
public MessageHandler handler3() {
//...
return handler3;
}
#MessagingGateway
public interface TestGateway{
#Gateway(requestChannel = "channel")
String method(String payload);
}
method expects some String as a return type. If a message is sent to all three handlers via channel, the value coming from which handler would be returned? From what I understand, messages are sent to each subscriber one by one, so would it be the value returned by the last handler?
Also, would it be possible to have handlers returning type different than the method return type, also if it wouldn't necessarily expect String?
When it comes to a scenario where any Exception occurs, I believe if setIgnoreFailures = false, the processing would stop on it and not process to the next handler. Otherwise, the last exception would be thrown.
Thanks in advance
I'm sure there is a specific business task behind your question.
But i you really are about an academic knowledge to see how Spring Integration works internally, then here is some answer for you.
Since your PublishSubscribeChannel is not configure with an Executor, then all your subscribers are called one by one, and only when the previous has done its job. And the part of that job is really a reply producing. So, if your first MessageHandler produced some reply, then exactly this one fulfills CountDownLatch in the TempraryReplyChannel for a gateway request-reply functionality.
The replies from the rest of handlers are going to be ignored and they may throw a late reply error.
Yes, you can return any type as long as it can be converted to the expected return type. See more info about ConversionService: https://docs.spring.io/spring-integration/reference/html/messaging-endpoints.html#payload-type-conversion
About ignoreFailures I'd suggest to look into a PublishSubscribeChannel source code and how it is propagated down to BroadcastingDispatcher:
private boolean invokeHandler(MessageHandler handler, Message<?> message) {
try {
handler.handleMessage(message);
return true;
}
catch (RuntimeException e) {
if (!this.ignoreFailures) {
if (e instanceof MessagingException && ((MessagingException) e).getFailedMessage() == null) { // NOSONAR
throw new MessagingException(message, "Failed to handle Message", e);
}
throw e;
}
else if (this.logger.isWarnEnabled()) {
logger.warn("Suppressing Exception since 'ignoreFailures' is set to TRUE.", e);
}
return false;
}
}
And no: otherwise none exception will be thrown. See that code again.

spring-integration MockIntegrationContext ReactiveStreamConsumer: IllegalArgumentException: 'subscriber' must not be null in the "...endpoint"

My test is failing because of the missing 'subscriber' field IllegalArgumentException: 'subscriber' must not be null in the "...endpoint"
#Test
public void test() throws InterruptedException {
ArgumentCaptor<Message<?>> captor = messageArgumentCaptor();
CountDownLatch receiveLatch = new CountDownLatch(1);
MessageHandler mockMessageHandler = mockMessageHandler(captor).handleNext(m -> receiveLatch.countDown());
this.mockIntegrationContext
.substituteMessageHandlerFor(
"test2.org.springframework.integration.config.ConsumerEndpointFactoryBean#1",
mockMessageHandler);
this.integrationFlowWithReactiveConsumerHandler.getInputChannel().send(new GenericMessage<>("test2"));
assertThat(receiveLatch.await(10, TimeUnit.SECONDS)).isTrue();
verify(mockMessageHandler).handleMessage(any());
assertThat(captor.getValue().getPayload())
.isEqualTo("reactive-message-text");
}
It's failing here in MockIntegrationContext.java, calling substituteMessageHandlerFor method, when endpoint is ReactiveStreamsConsumer
public void substituteMessageHandlerFor(String consumerEndpointId, // NOSONAR - complexity
MessageHandler mockMessageHandler, boolean autoStartup) {
Object endpoint = this.beanFactory.getBean(consumerEndpointId, IntegrationConsumer.class);
if (autoStartup && endpoint instanceof Lifecycle) {
((Lifecycle) endpoint).stop();
}
DirectFieldAccessor directFieldAccessor = new DirectFieldAccessor(endpoint);
Object targetMessageHandler = directFieldAccessor.getPropertyValue(HANDLER);
Assert.notNull(targetMessageHandler, () -> "'handler' must not be null in the: " + endpoint);
if (endpoint instanceof ReactiveStreamsConsumer) {
Object targetSubscriber = directFieldAccessor.getPropertyValue("subscriber");
Assert.notNull(targetSubscriber, () -> "'subscriber' must not be null in the: " + endpoint);
The handler endpoint bean is ...:reactive-outbound-channel-adapter which is being instantiated using ReactiveStreamConsumer constructor, where the 'subsciber' field is null by default.
/**
* Instantiate an endpoint based on the provided {#link MessageChannel} and {#link ReactiveMessageHandler}.
* #param inputChannel the channel to consume in reactive manner.
* #param reactiveMessageHandler the {#link ReactiveMessageHandler} to process messages.
* #since 5.3
*/
public ReactiveStreamsConsumer(MessageChannel inputChannel, ReactiveMessageHandler reactiveMessageHandler) {
Assert.notNull(inputChannel, "'inputChannel' must not be null");
this.inputChannel = inputChannel;
this.handler = new ReactiveMessageHandlerAdapter(reactiveMessageHandler);
this.reactiveMessageHandler = reactiveMessageHandler;
this.publisher = IntegrationReactiveUtils.messageChannelToFlux(inputChannel);
this.subscriber = null;
this.lifecycleDelegate =
reactiveMessageHandler instanceof Lifecycle ? (Lifecycle) reactiveMessageHandler : null;
}
During the test it creates the endpoint bean, and then during the substituteMessageHandlerFor it throws an exception of missing subscriber field
Integration flow is simple with single DB reactive handler.
Any ideas? Thanks a lot.
This is a bug in the testing framework. When we introduced a ReactiveMessageHandler support into that ReactiveStreamsConsumer, we just missed to adjust MockIntegrationContext logic respectively.
There is no way to mock a reactive endpoint at the moment as any reasonable workaround. However you can introduce some intermediate endpoint into the flow, e.g. bridge() and mock just this one without any return. So, your test will pass and nothing will be send to the real reactive endpoint in the end.
Feel free to raise a GH issue and we will look into that ASAP.

How to know which exception is thrown from errorhandler in dead letter queue listener?

I have a quorum queue (myQueue) and it's dead letter queue (myDLQueue). We have several exceptions which we separated as Retryable or Fatal. But sometimes in below listener we make an api call that throws RateLimitException. In this case the application should increase both of retry count and retry delay.
#RabbitListener(queues = "#{myQueue.getName()}", errorHandler = "myErrorHandler")
#SendTo("#{myStatusQueue.getName()}")
public Status process(#Payload MyMessage message, #Headers MessageHeaders headers) {
int retries = headerProcessor.getRetries(headers);
if (retries > properties.getMyQueueMaxRetries()) {
throw new RetriesExceededException(retries);
}
if (retries > 0) {
logger.info("Message {} has been retried {} times. Process it again anyway", kv("task_id", message.getTaskId()), retries);
}
// here we send a request to an api. but sometimes api returns rate limit error in case we send too many requests.
// In that case makeApiCall throws RateLimitException which extends RetryableException
makeApiCall() // --> it will throw RateLimitException
if(/* a condition that needs to retry sending the message*/) {
throw new RetryableException()
}
if(/* a condition that should not retry*/){
throw new FatalException()
}
return new Status("Step 1 Success!");
}
I have also an error handler (myErrorHandler) that catches thrown exceptions from above rabbit listener and manages retry process according to the type of the exception.
public class MyErrorHandler implements RabbitListenerErrorHandler {
#Override
public Object handleError(Message amqpMessage,
org.springframework.messaging.Message<?> message,
ListenerExecutionFailedException exception) {
// Check if error is fatal or retryable
if (exception.getCause() /* ..is fatal? */) {
return new Status("FAIL!");
}
// Retryable exception, rethrow it and let message to be NACKed and retried via DLQ
throw exception;
}
}
Last part I have is a DLQHandler that listens dead letter queue messages and send them to original queue (myQueue).
#Service
public class MyDLQueueHandler {
private final MyAppProperties properties;
private final MessageHeaderProcessor headerProcessor;
private final RabbitProducerService rabbitProducerService;
public MyDLQueueHandler(MyProperties properties, MessageHeaderProcessor headerProcessor, RabbitProducerService rabbitProducerService) {
this.properties = properties;
this.headerProcessor = headerProcessor;
this.rabbitProducerService = rabbitProducerService;
}
/**
* Since message TTL is not available with quorum queues manually listen DL Queue and re-send the message with delay.
* This allows messages to be processed again.
*/
#RabbitListener(queues = {"#{myDLQueue.getName()}"}"})
public void handleError(#Payload Object message, #Headers MessageHeaders headers) {
String routingKey = headerProcessor.getRoutingKey(headers);
Map<String, Object> newHeaders = Map.of(
MessageHeaderProcessor.DELAY, properties.getRetryDelay(), // I need to send increased delay in case of RateLimitException.
MessageHeaderProcessor.RETRIES_HEADER, headerProcessor.getRetries(headers) + 1
);
rabbitProducerService.sendMessageDelayed(message, routingKey, newHeaders);
}
}
In the above handleError method inputs there is not any information related to exception instance thrown from MyErrorHandler or MyQueue listener. Currently I have to pass retry delay by reading it from app.properties. But I need to increase this delay if RateLimitException is thrown. So my question is how do I know which error is thrown from MyErrorHandler while in the MyDLQueueHandler?
When you use the normal dead letter mechanism in RabbitMQ, there is no exception information provided - the message is the original rejected message. However, Spring AMQP provides a RepublishMessageRecoverer which can be used in conjunction with a retry interceptor. In that case, exception information is published in headers.
See https://docs.spring.io/spring-amqp/docs/current/reference/html/#async-listeners
The RepublishMessageRecoverer publishes the message with additional information in message headers, such as the exception message, stack trace, original exchange, and routing key. Additional headers can be added by creating a subclass and overriding additionalHeaders().
#Bean
RetryOperationsInterceptor interceptor() {
return RetryInterceptorBuilder.stateless()
.maxAttempts(5)
.recoverer(new RepublishMessageRecoverer(amqpTemplate(), "something", "somethingelse"))
.build();
}
The interceptor is added to the container's advice chain.
https://github.com/spring-projects/spring-amqp/blob/57596c6a26be2697273cd97912049b92e81d3f1a/spring-rabbit/src/main/java/org/springframework/amqp/rabbit/retry/RepublishMessageRecoverer.java#L55-L61
public static final String X_EXCEPTION_STACKTRACE = "x-exception-stacktrace";
public static final String X_EXCEPTION_MESSAGE = "x-exception-message";
public static final String X_ORIGINAL_EXCHANGE = "x-original-exchange";
public static final String X_ORIGINAL_ROUTING_KEY = "x-original-routingKey";
The exception type can be found in the stack trace header.

How to dead letter a RabbitMQ messages when an exceptions happens in a service after an aggregator's forceRelease

I am trying to figure out the best way to handle errors that might have occurred in a service that is called after a aggregate's group timeout occurred that mimics the same flow as if the releaseExpression was met.
Here is my setup:
I have a AmqpInboundChannelAdapter that takes in messages and send them to my aggregator.
When the releaseExpression has been met and before the groupTimeout has expired, if an exception gets thrown in my ServiceActivator, the messages get sent to my dead letter queue for all the messages in that MessageGroup. (10 messages in my example below, which is only used for illustrative purposes) This is what I would expect.
If my releaseExpression hasn't been met but the groupTimeout has been met and the group times out, if an exception gets throw in my ServiceActivator, then the messages do not get sent to my dead letter queue and are acked.
After reading another blog post,
link1
it mentions that this happens because the processing happens in another thread by the MessageGroupStoreReaper and not the one that the SimpleMessageListenerContainer was on. Once processing moves away from the SimpleMessageListener's thread, the messages will be auto ack.
I added the configuration mentioned in the link above and see the error messages getting sent to my error handler. My main question, is what is considered the best way to handle this scenario to minimize message getting lost.
Here are the options I was exploring:
Use a BatchRabbitTemplate in my custom error handler to publish the failed messaged to the same dead letter queue that they would have gone to if the releaseExpression was met. (This is the approach I outlined below but I am worried about messages getting lost, if an error happens during publishing)
Investigate if there is away I could let the SimpleMessageListener know about the error that occurred and have it send the batch of messages that failed to a dead letter queue? I doubt this is possible since it seems the messages are already acked.
Don't set the SimpleMessageListenerContainer to AcknowledgeMode.AUTO and manually ack the messages when they get processed via the Service when the releaseExpression being met or the groupTimeOut happening. (This seems kinda of messy, since there can be 1..N message in the MessageGroup but wanted to see what others have done)
Ideally, I want to have a flow that will that will mimic the same flow when the releaseExpression has been met, so that the messages don't get lost.
Does anyone have recommendation on the best way to handle this scenario they have used in the past?
Thanks for any help and/or advice!
Here is my current configuration using Spring Integration DSL
#Bean
public SimpleMessageListenerContainer workListenerContainer() {
SimpleMessageListenerContainer container =
new SimpleMessageListenerContainer(rabbitConnectionFactory);
container.setQueues(worksQueue());
container.setConcurrentConsumers(4);
container.setDefaultRequeueRejected(false);
container.setTransactionManager(transactionManager);
container.setChannelTransacted(true);
container.setTxSize(10);
container.setAcknowledgeMode(AcknowledgeMode.AUTO);
return container;
}
#Bean
public AmqpInboundChannelAdapter inboundRabbitMessages() {
AmqpInboundChannelAdapter adapter = new AmqpInboundChannelAdapter(workListenerContainer());
return adapter;
}
I have defined a error channel and defined my own taskScheduler to use for the MessageStoreRepear
#Bean
public ThreadPoolTaskScheduler taskScheduler(){
ThreadPoolTaskScheduler ts = new ThreadPoolTaskScheduler();
MessagePublishingErrorHandler mpe = new MessagePublishingErrorHandler();
mpe.setDefaultErrorChannel(myErrorChannel());
ts.setErrorHandler(mpe);
return ts;
}
#Bean
public PollableChannel myErrorChannel() {
return new QueueChannel();
}
public IntegrationFlow aggregationFlow() {
return IntegrationFlows.from(inboundRabbitMessages())
.transform(Transformers.fromJson(SomeObject.class))
.aggregate(a->{
a.sendPartialResultOnExpiry(true);
a.groupTimeout(3000);
a.expireGroupsUponCompletion(true);
a.expireGroupsUponTimeout(true);
a.correlationExpression("T(Thread).currentThread().id");
a.releaseExpression("size() == 10");
a.transactional(true);
}
)
.handle("someService", "processMessages")
.get();
}
Here is my custom error flow
#Bean
public IntegrationFlow errorResponse() {
return IntegrationFlows.from("myErrorChannel")
.<MessagingException, Message<?>>transform(MessagingException::getFailedMessage,
e -> e.poller(p -> p.fixedDelay(100)))
.channel("myErrorChannelHandler")
.handle("myErrorHandler","handleFailedMessage")
.log()
.get();
}
Here is the custom error handler
#Component
public class MyErrorHandler {
#Autowired
BatchingRabbitTemplate batchingRabbitTemplate;
#ServiceActivator(inputChannel = "myErrorChannelHandler")
public void handleFailedMessage(Message<?> message) {
ArrayList<SomeObject> payload = (ArrayList<SomeObject>)message.getPayload();
payload.forEach(m->batchingRabbitTemplate.convertAndSend("some.dlq","#", m));
}
}
Here is the BatchingRabbitTemplate bean
#Bean
public BatchingRabbitTemplate batchingRabbitTemplate() {
ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
scheduler.setPoolSize(5);
scheduler.initialize();
BatchingStrategy batchingStrategy = new SimpleBatchingStrategy(10, Integer.MAX_VALUE, 30000);
BatchingRabbitTemplate batchingRabbitTemplate = new BatchingRabbitTemplate(batchingStrategy, scheduler);
batchingRabbitTemplate.setConnectionFactory(rabbitConnectionFactory);
return batchingRabbitTemplate;
}
Update 1) to show custom MessageGroupProcessor:
public class CustomAggregtingMessageGroupProcessor extends AbstractAggregatingMessageGroupProcessor {
#Override
protected final Object aggregatePayloads(MessageGroup group, Map<String, Object> headers) {
return group;
}
}
Example Service:
#Slf4j
public class SomeService {
#ServiceActivator
public void processMessages(MessageGroup messageGroup) throws IOException {
Collection<Message<?>> messages = messageGroup.getMessages();
//Do business logic
//ack messages in the group
for (Message<?> m : messages) {
com.rabbitmq.client.Channel channel = (com.rabbitmq.client.Channel)
m.getHeaders().get("amqp_channel");
long deliveryTag = (long) m.getHeaders().get("amqp_deliveryTag");
log.debug(" deliveryTag = {}",deliveryTag);
log.debug("Channel = {}",channel);
channel.basicAck(deliveryTag, false);
}
}
}
Updated integrationFlow
public IntegrationFlow aggregationFlowWithCustomMessageProcessor() {
return IntegrationFlows.from(inboundRabbitMessages()).transform(Transformers.fromJson(SomeObject.class))
.aggregate(a -> {
a.sendPartialResultOnExpiry(true);
a.groupTimeout(3000);
a.expireGroupsUponCompletion(true);
a.expireGroupsUponTimeout(true);
a.correlationExpression("T(Thread).currentThread().id");
a.releaseExpression("size() == 10");
a.transactional(true);
a.outputProcessor(new CustomAggregtingMessageGroupProcessor());
}).handle("someService", "processMessages").get();
}
New ErrorHandler to do nack
public class MyErrorHandler {
#ServiceActivator(inputChannel = "myErrorChannelHandler")
public void handleFailedMessage(MessageGroup messageGroup) throws IOException {
if(messageGroup!=null) {
log.debug("Nack messages size = {}", messageGroup.getMessages().size());
Collection<Message<?>> messages = messageGroup.getMessages();
for (Message<?> m : messages) {
com.rabbitmq.client.Channel channel = (com.rabbitmq.client.Channel)
m.getHeaders().get("amqp_channel");
long deliveryTag = (long) m.getHeaders().get("amqp_deliveryTag");
log.debug("deliveryTag = {}",deliveryTag);
log.debug("channel = {}",channel);
channel.basicNack(deliveryTag, false, false);
}
}
}
}
Update 2 Added custom ReleaseStratgedy and change to aggegator
public class CustomMeasureGroupReleaseStratgedy implements ReleaseStrategy {
private static final int MAX_MESSAGE_COUNT = 10;
public boolean canRelease(MessageGroup messageGroup) {
return messageGroup.getMessages().size() >= MAX_MESSAGE_COUNT;
}
}
public IntegrationFlow aggregationFlowWithCustomMessageProcessorAndReleaseStratgedy() {
return IntegrationFlows.from(inboundRabbitMessages()).transform(Transformers.fromJson(SomeObject.class))
.aggregate(a -> {
a.sendPartialResultOnExpiry(true);
a.groupTimeout(3000);
a.expireGroupsUponCompletion(true);
a.expireGroupsUponTimeout(true);
a.correlationExpression("T(Thread).currentThread().id");
a.transactional(true);
a.releaseStrategy(new CustomMeasureGroupReleaseStratgedy());
a.outputProcessor(new CustomAggregtingMessageGroupProcessor());
}).handle("someService", "processMessages").get();
}
There are some flaws in your understanding.If you use AUTO, only the last message will be dead-lettered when an exception occurs. Messages successfully deposited in the group, before the release, will be ack'd immediately.
The only way to achieve what you want is to use MANUAL acks.
There is no way to "tell the listener container to send messages to the DLQ". The container never sends messages to the DLQ, it rejects a message and the broker sends it to the DLX/DLQ.

can we batch up groups of 10 message load in mosquitto using spring integration

this is how i have defined my mqtt connection using spring integration.i am not sure whether this is possible bt can we setup a mqtt subscriber works after getting a 10 load of messages. right now subscriber works after publishing a message as it should.
#Autowired
ConnectorConfig config;
#Bean
public MqttPahoClientFactory mqttClientFactory() {
DefaultMqttPahoClientFactory factory = new DefaultMqttPahoClientFactory();
factory.setServerURIs(config.getUrl());
factory.setUserName(config.getUser());
factory.setPassword(config.getPass());
return factory;
}
#Bean
public MessageProducer inbound() {
MqttPahoMessageDrivenChannelAdapter adapter =
new MqttPahoMessageDrivenChannelAdapter(config.getClientid(), mqttClientFactory(), "ALERT", "READING");
adapter.setCompletionTimeout(5000);
adapter.setConverter(new DefaultPahoMessageConverter());
adapter.setQos(1);
adapter.setOutputChannel(mqttRouterChannel());
return adapter;
}
/**this is router**/
#MessageEndpoint
public class MessageRouter {
private final Logger logger = LoggerFactory.getLogger(MessageRouter.class);
static final String ALERT = "ALERT";
static final String READING = "READING";
#Router(inputChannel = "mqttRouterChannel")
public String route(#Header("mqtt_topic") String topic){
String route = null;
switch (topic){
case ALERT:
logger.info("alert message received");
route = "alertTransformerChannel";
break;
case READING:
logger.info("reading message received");
route = "readingTransformerChannel";
break;
}
return route;
}
}
i need to batch up groups of 10 messages at a time
That is not a MqttPahoMessageDrivenChannelAdapter responsibility.
We use there MqttCallback with this semantic:
* #param topic name of the topic on the message was published to
* #param message the actual message.
* #throws Exception if a terminal error has occurred, and the client should be
* shut down.
*/
public void messageArrived(String topic, MqttMessage message) throws Exception;
So, we can't batch them there on this Channel Adapter by nature of the Paho client.
What we can suggest you from the Spring Integration perspective is an Aggregator EIP implementation.
In your case you should add #ServiceActivator for the AggregatorFactoryBean #Bean before that mqttRouterChannel, before sending to the router.
That maybe as simple as:
#Bean
#ServiceActivator(inputChannel = "mqttAggregatorChannel")
AggregatorFactoryBean mqttAggregator() {
AggregatorFactoryBean aggregator = new AggregatorFactoryBean();
aggregator.setProcessorBean(new DefaultAggregatingMessageGroupProcessor());
aggregator.setCorrelationStrategy(m -> 1);
aggregator.setReleaseStrategy(new MessageCountReleaseStrategy(10));
aggregator.setExpireGroupsUponCompletion(true);
aggregator.setSendPartialResultOnExpiry(true);
aggregator.setGroupTimeoutExpression(new ValueExpression<>(1000));
aggregator.setOutputChannelName("mqttRouterChannel");
return aggregator;
}
See more information in the Reference Manual.

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