[CXF-8022] Thread hangs using Reactor Flux when Exeption is Thrown

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 3.2.8, 3.3.1
• Fix Version/s: 3.2.9, 3.3.2
• Component/s: JAX-RS
• Labels: cxf reactor spring-boot

Environment

• JDK 11
• CXF 3.3.1
• Spring Boot (latest)
• Undertow (latest)
• Reactor (latest)

• Estimated Complexity: Unknown
• Flags: Important
• Assignee: Andriy Redko
• Reporter: KimJohn Quinn
• Created: 15/Apr/19 21:59
• Updated: 13/May/19 18:08
• Resolved: 21/Apr/19 16:10

Description

We have run into a serious issue that was not expected or caught until late 
it appears with CXF and Reactor in Undertow (using Spring Boot)... 

The Flux throws an exception inside and hangs infinitely, requiring the 
process to be forcibly killed (kill -9).   

We are using Spring Boot (latest), CXF (latest) with Reactor extension, 
Undertow and Reactor.  Has anyone run into this and are there or could there 
be any potential work around to handle this?

We wanted to stick with using CXF for both our standard REST resources and Reactor resources because CXF has always worked well for us plus we are using the OpenAPI swagger integration.  Not being able to resolve this or have an established workaround may cause us to have to completely revert to Spring controllers.

There seems to be a problem with the onComplete handling of Fluxes when it 
throws a RuntimeException.  Basically, if you try to the endpoint, it will 
hang.  I've tracked it down to the writeTo function in 
StreamingAsyncSubscriber where the queue is empty but "completed" is still 
false so it goes into an infinite loop.  You can repeat it by running the 
code below. 

   @Path("/errors") 
   @Produces(APPLICATION_JSON) 
   public Flux<String> errors() 
   { 
       Flux<String> response =  Flux 
               .range(1, 5) 
               .flatMap(item-> 
               { 
                   if (item <=4) 
                   { 
                       return Mono.just("item: " + item); 
                   } 
                   else 
                   { 
                       System.out.println("---Hitting exception"); 
                       return Mono.error(new RuntimeException("runtime 
error")); 
                   } 
               }); 

       return response; 
   } 

 

I also posted this on the forums hoping someone can assist - http://cxf.547215.n5.nabble.com/Thread-hangs-when-using-reactor-cxf-and-undertow-td5796369.html

 

The log output, up until manually killing the process looks like:

[DEBUG] o.a.c.j.interceptor.JAXRSInInterceptor : Found operation: errors
[DEBUG] o.apache.cxf.phase.PhaseInterceptorChain : Invoking handleMessage on interceptor org.apache.cxf.interceptor.OneWayProcessorIntercep tor@6e760b48
[DEBUG] o.apache.cxf.phase.PhaseInterceptorChain : Invoking handleMessage on interceptor org.apache.cxf.interceptor.ServiceInvokerIntercept or@6d7702a0
[DEBUG] o.a.cxf.service.invoker.AbstractInvoker : Invoking method public reactor.core.publisher.Flux io.logicdrop.drools.endpoints.DroolsR ulesetResource.errors() on object io.logicdrop.drools.endpoints.DroolsRulesetResource@23718909 with params [].
[DEBUG] reactor.util.Loggers$LoggerFactory : Using Slf4j logging framework
---Hitting exception
[DEBUG] o.apache.cxf.phase.PhaseInterceptorChain : Invoking handleMessage on interceptor org.apache.cxf.interceptor.OutgoingChainIntercepto r@308be65a
[DEBUG] o.a.c.i.OutgoingChainInterceptor : Interceptors contributed by bus: []
[DEBUG] o.a.c.i.OutgoingChainInterceptor : Interceptors contributed by service: []
[DEBUG] o.a.c.i.OutgoingChainInterceptor : Interceptors contributed by endpoint: [org.apache.cxf.interceptor.MessageSenderIntercept or@3f0061c3]
[DEBUG] o.a.c.i.OutgoingChainInterceptor : Interceptors contributed by binding: [org.apache.cxf.jaxrs.interceptor.JAXRSOutIntercept or@5419dbea]
[DEBUG] o.apache.cxf.phase.PhaseInterceptorChain : Adding interceptor org.apache.cxf.interceptor.MessageSenderInterceptor@3f0061c3 to phase prepare-send
[DEBUG] o.apache.cxf.phase.PhaseInterceptorChain : Adding interceptor org.apache.cxf.jaxrs.interceptor.JAXRSOutInterceptor@5419dbea to phas e marshal
[DEBUG] o.apache.cxf.phase.PhaseInterceptorChain : Chain org.apache.cxf.phase.PhaseInterceptorChain@63b5b52 was created. Current flow:
prepare-send [MessageSenderInterceptor]
marshal [JAXRSOutInterceptor]

[DEBUG] o.apache.cxf.phase.PhaseInterceptorChain : Invoking handleMessage on interceptor org.apache.cxf.interceptor.MessageSenderIntercepto r@3f0061c3
[DEBUG] o.apache.cxf.phase.PhaseInterceptorChain : Adding interceptor org.apache.cxf.interceptor.MessageSenderInterceptor$MessageSenderEndi ngInterceptor@30cf09f to phase prepare-send-ending
[DEBUG] o.apache.cxf.phase.PhaseInterceptorChain : Chain org.apache.cxf.phase.PhaseInterceptorChain@63b5b52 was modified. Current flow:
prepare-send [MessageSenderInterceptor]
marshal [JAXRSOutInterceptor]
prepare-send-ending [MessageSenderEndingInterceptor]

[DEBUG] o.apache.cxf.phase.PhaseInterceptorChain : Invoking handleMessage on interceptor org.apache.cxf.jaxrs.interceptor.JAXRSOutIntercept or@5419dbea
[DEBUG] o.a.c.j.interceptor.JAXRSOutInterceptor : Response content type is: application/json
[DEBUG] o.apache.cxf.ws.addressing.ContextUtils : retrieving MAPs from context property javax.xml.ws.addressing.context.inbound
[DEBUG] o.apache.cxf.ws.addressing.ContextUtils : WS-Addressing - failed to retrieve Message Addressing Properties from context

Same scenario with a Mono appears to show the stream "completing"...

Issue Links

• relates to: CXF-8023 Refactor systest/jaxrs/reactor/* test cases to use StepVerifier
• links to: GitHub Pull Request #542