I'm new at Spring AMQP. I wanna use sendAndReceive() with using custom message.
public void send (String exchange, String routingKey, MyCustomMessage message){
CorrelationData correlationData = new CorrelationData("correlation-data");
rabbitTemplate.sendAndReceive(exchange, routingKey, message, correlationData);
}
But this code occur error message
Make 'MyCustomMessage'extends org.springframework.amqp.core.Message'
Extending Message is the only way to use CustomMessage?
I didn't extend when I using convertAndSend function.
No; as long as it is compatible with the MessageConverter in the template (default SimpleMessageConverter can handle Serializable or you can use a Jackson2JsonMessageConverter for JSON-friendly classes, or you can use a custom message converter).
Then, use template.convertSendAndReceive(...) instead of sendAndReceive.
Related
I am using org.springframework.boot:spring-boot-starter-amqp:2.6.6 .
According to the documentation, I set up #RabbitListener - I use SimpleRabbitListenerContainerFactory and the configuration looks like this:
#Bean
public SimpleRabbitListenerContainerFactory rabbitListenerContainerFactory(ObjectMapper om) {
SimpleRabbitListenerContainerFactory factory = new SimpleRabbitListenerContainerFactory();
factory.setConnectionFactory(connectionFactory());
factory.setAcknowledgeMode(AcknowledgeMode.MANUAL);
factory.setConcurrentConsumers(rabbitProperties.getUpdater().getConcurrentConsumers());
factory.setMaxConcurrentConsumers(rabbitProperties.getUpdater().getMaxConcurrentConsumers());
factory.setMessageConverter(new Jackson2JsonMessageConverter(om));
factory.setAutoStartup(rabbitProperties.getUpdater().getAutoStartup());
factory.setDefaultRequeueRejected(false);
return factory;
}
The logic of the service is to receive messages from rabbitmq, contact an external service via the rest API (using rest template) and put some information into the database based on the results of the response (using spring data jpa). The service implemented it successfully, but during testing it ran into problems that if any exceptions occur during the work of those thrown up the stack, the message is not sent to the configured dlq, but simply hangs in the broker as unacked. Can you please tell me how you can tell spring amqp that if any error occurs, you need to redirect the message to dlq?
The listener itself looks something like this:
#RabbitListener(
queues = {"${rabbit.updater.consuming.queue.name}"},
containerFactory = "rabbitListenerContainerFactory"
)
#Override
public void listen(
#Valid #Payload MessageDTO message,
Channel channel,
#Header(AmqpHeaders.DELIVERY_TAG) Long deliveryTag
) {
log.debug(DebugMessagesConstants.RECEIVED_MESSAGE_FROM_QUEUE, message, deliveryTag);
messageUpdater.process(message);
channel.basicAck(deliveryTag, false);
log.debug(DebugMessagesConstants.PROCESSED_MESSAGE_FROM_QUEUE, message, deliveryTag);
}
In rabbit managment it look something like this:
enter image description here
and unacked will hang until the queue consuming application stops
See error handling documentation: https://docs.spring.io/spring-amqp/docs/current/reference/html/#annotation-error-handling.
So, you just don't do an AcknowledgeMode.MANUAL and rely on the Dead Letter Exchange configuration for those messages which are rejected in case of error.
Or try to use a this.channel.basicNack(deliveryTag, false, false) in case of messageUpdater.process(message); exception...
Let's take the following consumer method for a RabbitMQ queue. Ths payload received from the queue is in JSON format, so I register a bean returning a Jackson2JsonMessageConverter. This basically works fine.
Now I'd like to add a validation of the QueueResponse object, similar to when using Jackson in a #RestController, e.g. if the JSON field does not exist or contains an invalid value. In this case, I'd like the code to execute the catch block, i.e. throwing an AmqpRejectAndDontRequeueException.
Thus, I added #Payload #Valid as described in the documentation. But I don't know what to do in the validationErrorHandler method. I don't understand the return statement from the documentation. What would I need to do there to reach the catch block?
#RabbitListener(queues = QUEUE_NAME, messageConverter = "jackson2MessageConverter", errorHandler="validationErrorHandler")
public void consume(#Payload #Valid QueueResponse queueResponse) {
try {
processMessage(queueResponse);
} catch (Exception e) {
throw new AmqpRejectAndDontRequeueException(e.getMessage());
}
}
#Bean
public MessageConverter jackson2MessageConverter() {
return new Jackson2JsonMessageConverter(objectMapper);
}
// Not sure what to do here...
#Bean
public RabbitListenerErrorHandler validationErrorHandler() {
return (m, e) -> {
...
};
}
If the error handler exits normally, the message will be acknowledged (discarded).
If the error handler throws an exception, the message will either be requeued (and redelivered) or discarded (and optionally sent to a dead letter queue), depending on the exception type, container properties, and queue arguments.
Basically what I do in the RabbitListenerErrorHandler is the following:
check how many times I requeued a message by looking into the count property in the x-death header
then decide to either requeue the message by throwing an AmqpRejectAndDontRequeueException or not. In this last case, instead of just discard the message, send it to a parking-lot exchange (bound to a queue with no consumer, in my case these queues are monitored externally) with additional information (for instance the stack trace of the last failure)
I have a simple TCP connection factory implemented in Spring Integration:
#Bean
#ServiceActivator(inputChannel = "toTcpChannel")
public TcpSendingMessageHandler tcpOutClient() throws Exception {
TcpSendingMessageHandler sender = new TcpSendingMessageHandler();
sender.setConnectionFactory(clientFactory());
sender.setClientMode(false);
sender.afterPropertiesSet();
return sender;
}
#Bean
public AbstractClientConnectionFactory clientFactory() {
final TcpNioClientConnectionFactory factory = new TcpNioClientConnectionFactory(tcpHost, tcpPort);
factory.setSingleUse(true);
return factory;
}
#EventListener
public void handleTcpConnectionOpenEvent(TcpConnectionOpenEvent event) throws Exception {
LOGGER.info("TCP connection OPEN event: {}", event.getConnectionId());
// HERE I would like to have "myCustomID" header here.
}
I am looking for getting the custom ID that I am providing via Gateway in the produced TcpConnectionOpenEvent (or similar via interceptors)
#Gateway(requestChannel="toTcpChannel")
public void sendToTcp(#Payload String message, #Header("myCustomID") Long myCustomID);
I know this is an event not a message but I do know how to get the Connection ID that I will receive in the input channel in any other way.
I am creating a type of hash map of my custom id – connection id.
I cannot use a custom correlation via aggregator because the response message will not contain any information about the previously sent message. Any suggestions will be welcome.
Oh! I see. Not sure what you are going to do from your custom TcpSendingMessageHandler, but as far as ApplicationEventPublisher is single-threaded, you can store the connectionId in the ThreadLocal variable and obtain it from there after send operation.
I want to send a message to websocket subscribers of a specific record - when an action takes place in one of my service class.
I'm trying to read the Spring Websocket documentation but it's kind of ambiguous to the point of how to get all these things working together.
Here are my setup files (this is extending jHipster btw):
WebsocketConfiguration.java
#Override
public void configureMessageBroker(MessageBrokerRegistry config) {
config.enableStompBrokerRelay("/queue/", "/topic/", "/exchange/");
config.setApplicationDestinationPrefixes("/app");
config.setPathMatcher(new AntPathMatcher("."));
}
#Override
public void registerStompEndpoints(StompEndpointRegistry registry) {
registry.addEndpoint("/ws").withSockJS();
}
WebsocketSecurity.java
#Override
protected void configureInbound(MessageSecurityMetadataSourceRegistry messages) {
messages
// message types other than MESSAGE and SUBSCRIBE
.nullDestMatcher().authenticated()
// matches any destination that starts with /rooms/
.simpDestMatchers("/topic/tracker").hasAuthority(AuthoritiesConstants.ADMIN)
.simpDestMatchers("/topic/**").authenticated()
// (i.e. cannot send messages directly to /topic/, /queue/)
// (i.e. cannot subscribe to /topic/messages/* to get messages sent to
// /topic/messages-user<id>)
.simpTypeMatchers(SimpMessageType.MESSAGE, SimpMessageType.SUBSCRIBE).denyAll()
// catch all
.anyMessage().denyAll();
}
Controller class (attempt at implementing a simple broker I can test subscribing to from sockjs and recieving messages generated elsewhere in the application:
#MessageMapping("/ws")
#SendTo("/topic/sendactivity.{id}")
public void activity(#DestinationVariable string id, #Payload String message){
log.debug("Sending command center: "+message);
}
#RequestMapping(value = "/updateactivity", method = RequestMethod.PUT)
public ResponseEntity<Membership> updateMembership(
#RequestBody Membership membership) throws URISyntaxException {
// ...
String testString = "test";
messagingTemplate.convertAndSend("/topic/commandcenter"+membership.getId().toString(), testString);
// ...
}
When I put a breakpoint on the public void activity method, I don't get anything?
Sending a message to "/topic/commandcenterID" using the messaging template will send that message to the message broker, which will dispatch that message to clients subscribed to that topic. So it won't flow through your activity method.
When using #MessageMapping annotated methods, you're declaring those as application destinations. So sending a message to "/app/ws" should map to that method. Note that in that case I doubt it'll work since the destination variable you're expecting as a method argument is missing from the path definition in the #MessageMapping annotation.
Also, the #SendTo annotation in fact tells Spring that the value returned by the method should be converted to a message and sent to the given destination.
It seems you're mixing things up here, and I think you should:
read carefully the flow of messages in Spring STOMP support
look at a few example apps like the websocket portfolio and websocket chat
I'm have to implement custom API over Websockets that requires:
Custom WAMP-like subprotocol
Path parameters in socket URI
So I've following questions:
Is there any documentation or guides on implementing custom subprotocols in Spring? Protocol requires that exact version must be specified in the Sec-Websocket-Protocol field. Where this field could be read on server side?
What is a proper way to pass path parameters into a message handler? I could use ant patterns in handler registration
#Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry.addHandler(customHandler(), "/api/custom/{clientId}");
}
but those seems not available at TextWebSocketHandler. I'm solved this for now by extending default HttpSessionHandshakeInterceptor in a following way:
public class CustomHandshakeInterceptor extends HttpSessionHandshakeInterceptor {
private static final UriTemplate URI_TEMPLATE = new UriTemplate("/api/custom/{clientId}");
#Override
public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response,
WebSocketHandler wsHandler, Map<String, Object> attributes) throws Exception {
Map<String, String> segments = URI_TEMPLATE.match(request.getURI().getPath());
attributes.put("CLIENTID", segments.get("clientId"));
return super.beforeHandshake(request, response, wsHandler, attributes);
}
}
and then accessing it in TextWebSocketHandler:
public class CustomHandler extends TextWebSocketHandler {
#Override
protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
super.handleTextMessage(session, message);
String clientId = session.getAttributes().get("CLIENTID");
...
session.sendMessage(response);
}
}
but this method, in my opinion, is a bit clunky. Is there more proper way to solve this?
Thanks.
The best advice I could give is to follow the example of the sub-protocol support that's built in -- starting with SubProtocolWebSocketHandler and the SubProtocolHandler's it delegates to including the StompSubProtocolHandler implementation. The SubProtocolWebSocketHandler is further connected to "clientInbound" and "clientOutbound" channels which are then used to form a processing flow as well as to provide thread boundaries.
There is a description for the processing flow for STOMP http://docs.spring.io/spring/docs/current/spring-framework-reference/html/websocket.html#websocket-stomp-message-flow which includes delegating messages to annotated controllers and/or to a message broker which can also send messages back downstream to clients.
Essentially the StompSubProtocolHandler translates to and from a WebSocketMessage and a Spring Message with protocol-specific content. So that controllers, message brokers, or any other consumer of the messages from the client inbound channel are decoupled and unaware from the WebSocket transport layer. Many of the facilities built around the building, sending, and processing of such sub-protocol messages are meant to be potentially usable for support of other STOMP-like protocols. That includes all the classes in the org.springframework.messaging.simp package.
As for URL path parameters, Spring doesn't provide anything at the WebSocket level which is mostly a transport layer. Most of the interesting stuff happens at the sub-protocol level. For example for STOMP a MessageMapping is supported based on the destination header along with a #DestinationVariable which is comparable to using #PathVariable in Spring MVC but based on the destination header, not the URL.