SseEmitter onError method does not get called on Payara 5

[hsynff]

I'm trying below code on Spring MVC (5.1.8 version of dependencies) deployed on Payara 5 :

`@GetMapping("/listen-sse")
public SseEmitter sseEmitter() {
SseEmitter emitter = new SseEmitter(0L);
emitter.onError(e -> System.out.println("OnError"));

ExecutorService service = Executors.newCachedThreadPool();
service.execute(() -> {
    while (true) {
        try {
            Thread.sleep(2000);
            emitter.send("Hello");
        } catch (IOException | InterruptedException e) {
            System.out.println("Exception");
            break;
        }
    }
});

service.shutdown();
return emitter;
}`

When the client disconnects I can only see "Exception" on console but not "OnError". I've tried to deploy same war file to Tomcat 8.5.42 everything works as expected.

[rdebusscher]

Hi @hsynff,

Can you create a small test application so that we can try to reproduce this problem?

Regards Rudy

[hsynff]

Hello. https://github.com/hsynff/sse-test

Kindly, clone this repo.

• Deploy to Payara server and run the project.
• Open the index page and click "Listen SSE".
• data:Hello will sent by the server sequentially. Try to close the browser tab and look at the server logs. You'll see only "Exception" but not "OnError".
• You can deploy the same project to Tomcat 8.x version, try the above steps and "OnError" will be printed.

I'm using below versions: Payara 5.193 Java 1.8_211 (also tried with 1.8_221)

[hsynff]

Hello. Is there any progress? We are going to deploy to production next week, so I have to decide if we must to migrate to the Tomcat or stay in Payara.

[OndroMih]

Hi @hsynff, I tried your reproducer and it gives me exceptions during deployment. Those exceptions are due to a known bug #4060. It's not yet fixed but there's a workaround described in that issue:

Patching jackson-dataformat-xml.jar in the glassfish/modules directory worked as a workaround for us: We changed MANIFEST.MF to allow for stax4 between 3 and 5. It was org.codehaus.stax2;version="[3.1,4)", org.codehaus.stax2.io;version="[3.1,4)",org.codehaus.stax2.ri;version="[3.1,4)" We patched it to be org.codehaus.stax2;version="[3.1,5)", org.codehaus.stax2.io;version="[3.1,5)",org.codehaus.stax2.ri;version="[3.1,5)"

[hsynff]

Yes, I know those exceptions but it's not mandatory for now. Our problem is quite different as I've noted above

[OndroMih]

I debugged the Spring's SseEmitter and I see no way how it triggers the onError method. The emitter just throws an exception, without calling the onError method, there's no code to do that and I'd say it's a bug in Spring. I'll try with Tomcat to see how it's possible that the onError is triggered.

[hsynff]

It works on Tomcat. I've raised same issue on spring issues page and they said that it is related to the container, so there may be a bug in Payara. https://github.com/spring-projects/spring-framework/issues/23668

[OndroMih]

In Tomcat, the onError method is triggered from the Spring's StandardServletAsyncWebRequest, which implements javax.servlet.AsyncListener. I assume that Spring registers the async listener with Tomcat but fails to do so with Payara.

[hsynff]

So is it the issue from Spring or Payara? What should we do for now?

[OndroMih]

I'm really not sure. It looks like Spring registers the async listener but Payara Server doesn't trigger it. It requires more investigation and unfortunately I don't have time for that now.

[hsynff]

Thanks for your time. So I'm gonna close this issue and assume the official feedback from Payara is that "We don't have time for that now" right?

[smillidge]

Yep that's the response from the open source project. You can purchase support for a response with a SLA

[smillidge]

I'll leave open as it seems to be a valid issue

[OndroMih]

To summarize my findings for future investigation:

• the StandardServletAsyncWebRequest class in spring-web is an AsyncListener, which reportes error to the SseEmitter onError handler. Spring creates an async context and registers this listener to it after the SSE Spring controller method returns. This happens on both Payara and Tomcat
• Tomcat triggers this listener when I/O error is detected (connection is closed). Payara doesn't, I couldn't find out why.

Payara async context is implemented in AsyncContextImpl

[AlanRoth]

Hi, due to how long ago this issue was raised we have decided to close the issue immediately, and not consider the implementation of the fix/improvement that was requested. Please understand that this decision was taken into consideration with the resources that we have available at the moment. In case of having reported a bug, if the issue is still pressing to you, feel free to verify if it’s applicable in the current release of Payara Community edition, and proceed to raise a new issue with details of the test reproducer. Many thanks for your understanding.