We Keep Coding

Specify server request timeout in Spring Boot & Spring WebFlux (Netty)

We are using Spring Boot in 2.4.2 with Spring WebFlux.
I want the Spring Boot application to terminate all requests to the application that take longer than say 3 seconds to process.
There is server.netty.connection-timeout, but that doesn't seem to do the trick.
Is there a way to specify such a server request timeout?

I was also facing the same issue i.e. even after configuring server.netty.connection-timeout request would get canceled. So, after some debugging found that timeout was getting set to '30000' by AsyncContext.
So, I configured the following property spring.mvc.async.request-timeout which change the timeout being set in AsyncContext and the request stopped getting canceled.

TL;DR:
Netty has no request timeout*. Add this WebFilter to set a request-timeout of 3 seconds using the reactor timeout on every request (here in kotlin, but in Java it works accordingly):
#Component
class RequestTimeoutWebFilter : WebFilter {
override fun filter(exchange: ServerWebExchange, chain: WebFilterChain): Mono<Void> {
return chain
.filter(exchange)
.timeout(Duration.ofSeconds(3))
}
}
* at least I could not find any information in the netty docs.
Detailed answer
The connection-timeout does not refer to the duration that a request is allowed to take for processing, but it refers to the time it takes for establishing the connection.
First, I could not find any spring configuration option that allows setting the request timeout for netty. Then I went through the netty documentation to find out that there is no concept of request timeouts on the http server (only on the http client).
Wondering about why such important feature would not be supported, I remembered that we often cannot apply the same concepts as in blocking servers for good reasons. Next, I remembered, that in the reactive world we do not directly implement the handling of the request, but how the handling is assembled - i.e. we hold a Mono<Void> that will handle the request. Hence, we can just look at reactor and how to timeout a Mono, which is very easy:
Mono.create(...)
.timeout(Duration.ofSeconds(3))
Next, we just need to figure out, how to apply this to all requests. This is easy as well, because we can just use a WebFilter to intercept all requests to apply our timeout (here in kotlin, but in Java it works accoringly):
#Component
class RequestTimeoutWebFilter : WebFilter {
override fun filter(exchange: ServerWebExchange, chain: WebFilterChain): Mono<Void> {
return chain
.filter(exchange)
.timeout(Duration.ofSeconds(3))
}
}
This effectively cancels a request within the set timeout with the following error:
2022-10-21 00:08:00.981 ERROR 6289 --- [ parallel-4] a.w.r.e.AbstractErrorWebExceptionHandler : [59dfa990-7] 500 Server Error for HTTP GET "/some/route"
java.util.concurrent.TimeoutException: Did not observe any item or terminal signal within 3000ms in 'source(MonoDefer)' (and no fallback has been configured)
at reactor.core.publisher.FluxTimeout$TimeoutMainSubscriber.handleTimeout(FluxTimeout.java:295) ~[reactor-core-3.4.22.jar:3.4.22]
More tips and hints
To make the timeout configurable, we can use a custom config variable instead of the hard-coded duration.
To custimize the 500 status code we can either change the exception by providing a fallback to the timeout as 2nd argument and handle that exception in a controller advice - or we can just use reactors onErrorReturn.
The documentation for WebFilter actually states that they should be used to implement timeouts:
Contract for interception-style, chained processing of Web requests that may be used to implement cross-cutting, application-agnostic requirements such as security, timeouts, and others.
Still I think it is expected that spring provides such implementation out-of-the box that can be easily configured. Maybe we oversaw that it is there, but then I would argue it is too hard to find. ^^
Alternative solution path
As an alternative, we could use circuit breakers. However, those are implemented on the readers side and conceptually are used to protect the reading side against failure of the downstream - rather than protecting the internal processing within the downstream from running too long. They can only be applied to mimic a request timeout when applying them in a dedicated server (e.g. a spring cloud gateway server) that sits between the actual client and the actual service. When using Resilience4j as implementation, you can use TimeLimiter to achieve it.

Is it possible to return a application/json from a Spring Integration http inbound-channel-adapter?

I have an inbound-channel-adapter that forwards message to router and router has one mapping property which calls service activator where I am trying to trigger one REST POST service which accepts input JSON and produce output JSON.
In this case, service activator reutrns null but since http has to return a response.(In inbound-channel-adapter, I am using status-code-expression="T(org.springframework.http.HttpStatus).NO_CONTENT"
I'm using spring-integration v4.3.6

No, it’s possible. Since this component is one-way, there is nothing to return - just only status code header. By default it is 200 OK.
If you would like to return something, you should consider to use HTTP Inbound Gateway instead.
Otherwise your question isn’t clear

Spring AMQP MessageProperties:all headers were removed during deadlettering

I have got a question about Spring AMQP Message:
During processing I was able to update headers of message properties in String AMQP Message with some specific values.
After DeadLettering of this message, all specific headers were disappeared/removed.
Is this behaviour correct ?
Looking forward to your response.
Regards, Anton.
spring-rabbit.version: 1.3.5.RELEASE
spring.version: 4.1.1.RELEASE

The broker knows nothing about your client-side consumer changes; the original message (with its orignal headers) is dead-lettered by the broker (with an x-death header added to indicate the reason - rejection, expiry etc).
In order to do what you want, you need to publish your modified message yourself rather than using dead-lettering.
See the RepublishMessageRecoverer for an example using Spring retry. You can make a custom recover, or simply catch the exception in your listener to republish.

Spring MVC like processing of AMQP messages

What I want to do is process AMQP messages in a very similar way the Http Requests are processed using spring-webmvc annotations such as #RequestMapping, #RequestParam etc. But, instead of the Http Request my source object will be an AMQP message. The AMQP message request will have two headers, for example -
method="POST"
url="/api/myobjects/{someParam}"
and the payload will contain data in json format.
If you have noticed, this is nothing but HTTP REST api mapped to AMQP message.
I want to be able to write a controller like handler, for example -
#Controller
public class MyObjectHandler {
#RequestMapping(value="/api/myobjects/{someParam}", method="POST")
public MyObject createMyObject(#Payload MyObject myObj, #PathParam String someParam) {
//... some processing
return myObj;
}
// ...more handlers
}
I have looked at spring-amqp/rabbitmq annotations and also spring integration annotations. They are close to what I want, but would not allow routing to handler methods based on header parameters, especially the REST url.
I don't expect that a readymade solution would be available for this. Just want to make sure I choose the best possible option. Some of the options I think are (in order of precedence)
If the spring-webmvc annotation processing mechanism is extensible, just extend it to use AMQP message as source instead of Http Request
Modify the spring-webmvc annotation processing mechanism to take the AMQP message as input instead of Http Request
Write your own solution with custom annotaions and their processors, which I think is a very involving task
Or any other possible approach than above?
Any guidance/direction is appreciated.

I think the starting point is likely AbstractMethodMessageHandler in spring-messaging.
There's currently a SimpAnnotationMethodMessageHandler implementation for websockets which invokes #Controllers.
You could use a #RabbisListener method that has a Message<?> parameter (Spring AMQP will convert the underlying Rabbit message to a spring-messaging message, including the headers). Then, invoke the message handler to route to the appropriate controller method.
If you come up with a robust implementation, please consider contributing it.

Spring Integration Gateway with no arguments

On my gateway, I have a method
#Gateway
String commsTest();
The idea is that I can call commsTest from the bean and use spring integration to wire it up to the service activator that will check comms.
When I do that I get a receive is not supported, because no pollable reply channel has been configured error. I realise that this is because a method with no params means "I am trying to poll a message from the channel"
This is a two part question.
What does it mean to poll a message from the channel.
How can I get the functionality I want.

Spring Integration currently has no concept of a message without a payload. By default, a gateway method with no arguments implies you want to receive data (rather than sending data or sending and receiving data).
You can change that default behavior, as described in the reference documentation.