NullPointerException in EndpointServerWebExchangeMatcher.matches

[madgnome]

We're getting NPE in EndpointServerWebExchangeMatcher.matches when starting our service (Spring Boot 2.0.4)

java.lang.NullPointerException: null
	at org.springframework.boot.actuate.autoconfigure.security.reactive.EndpointRequest$EndpointServerWebExchangeMatcher.matches(EndpointRequest.java:238)
	at org.springframework.boot.security.reactive.ApplicationContextServerWebExchangeMatcher.matches(ApplicationContextServerWebExchangeMatcher.java:57)
	at org.springframework.security.web.server.MatcherSecurityWebFilterChain.matches(MatcherSecurityWebFilterChain.java:48)
	at org.springframework.security.web.server.WebFilterChainProxy.lambda$filter$0(WebFilterChainProxy.java:50)
	at reactor.core.publisher.FluxFilterWhen$FluxFilterWhenSubscriber.drain(FluxFilterWhen.java:242)
	at reactor.core.publisher.FluxFilterWhen$FluxFilterWhenSubscriber.onNext(FluxFilterWhen.java:131)
	at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onNext(ScopePassingSpanSubscriber.java:81)
	at reactor.core.publisher.FluxIterable$IterableSubscription.slowPath(FluxIterable.java:244)
	at reactor.core.publisher.FluxIterable$IterableSubscription.request(FluxIterable.java:202)
	at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.request(ScopePassingSpanSubscriber.java:69)
	at reactor.core.publisher.FluxFilterWhen$FluxFilterWhenSubscriber.onSubscribe(FluxFilterWhen.java:190)
	at org.springframework.cloud.sleuth.instrument.reactor.ScopePassingSpanSubscriber.onSubscribe(ScopePassingSpanSubscriber.java:63)
	at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:140)
	at reactor.core.publisher.FluxIterable.subscribe(FluxIterable.java:64)
	at reactor.core.publisher.FluxLiftFuseable.subscribe(FluxLiftFuseable.java:70)
	at reactor.core.publisher.FluxFilterWhen.subscribe(FluxFilterWhen.java:68)
	at reactor.core.publisher.FluxLift.subscribe(FluxLift.java:46)
	at reactor.core.publisher.MonoNext.subscribe(MonoNext.java:40)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoSwitchIfEmpty.subscribe(MonoSwitchIfEmpty.java:44)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoFlatMap.subscribe(MonoFlatMap.java:60)
	at reactor.core.publisher.MonoLiftFuseable.subscribe(MonoLiftFuseable.java:56)
	at reactor.core.publisher.MonoMapFuseable.subscribe(MonoMapFuseable.java:59)
	at reactor.core.publisher.MonoLiftFuseable.subscribe(MonoLiftFuseable.java:56)
	at reactor.core.publisher.MonoMapFuseable.subscribe(MonoMapFuseable.java:59)
	at reactor.core.publisher.MonoLiftFuseable.subscribe(MonoLiftFuseable.java:56)
	at reactor.core.publisher.MonoFlatMap.subscribe(MonoFlatMap.java:60)
	at reactor.core.publisher.MonoLiftFuseable.subscribe(MonoLiftFuseable.java:56)
	at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoPeek.subscribe(MonoPeek.java:71)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoPeek.subscribe(MonoPeek.java:71)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.Mono.subscribe(Mono.java:3080)
	at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:172)
	at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56)
	at reactor.core.publisher.MonoLiftFuseable.subscribe(MonoLiftFuseable.java:56)
	at reactor.core.publisher.MonoOnErrorResume.subscribe(MonoOnErrorResume.java:44)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoFlatMap.subscribe(MonoFlatMap.java:60)
	at reactor.core.publisher.MonoLiftFuseable.subscribe(MonoLiftFuseable.java:56)
	at reactor.core.publisher.MonoSubscriberContext.subscribe(MonoSubscriberContext.java:47)
	at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoPeekTerminal.subscribe(MonoPeekTerminal.java:61)
	at reactor.core.publisher.MonoLiftFuseable.subscribe(MonoLiftFuseable.java:56)
	at reactor.core.publisher.MonoPeekFuseable.subscribe(MonoPeekFuseable.java:74)
	at reactor.core.publisher.MonoLiftFuseable.subscribe(MonoLiftFuseable.java:56)
	at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:53)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoOnErrorResume.subscribe(MonoOnErrorResume.java:44)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoOnErrorResume.subscribe(MonoOnErrorResume.java:44)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.MonoOnErrorResume.subscribe(MonoOnErrorResume.java:44)
	at reactor.core.publisher.MonoLift.subscribe(MonoLift.java:46)
	at reactor.core.publisher.Mono.subscribe(Mono.java:3080)
	at reactor.core.publisher.MonoIgnoreThen$ThenIgnoreMain.drain(MonoIgnoreThen.java:172)
	at reactor.core.publisher.MonoIgnoreThen.subscribe(MonoIgnoreThen.java:56)
	at reactor.core.publisher.MonoLiftFuseable.subscribe(MonoLiftFuseable.java:56)
	at reactor.core.publisher.MonoPeekFuseable.subscribe(MonoPeekFuseable.java:74)
	at reactor.core.publisher.MonoLiftFuseable.subscribe(MonoLiftFuseable.java:56)
	at reactor.core.publisher.MonoPeekTerminal.subscribe(MonoPeekTerminal.java:61)
	at reactor.core.publisher.MonoLiftFuseable.subscribe(MonoLiftFuseable.java:56)
	at reactor.ipc.netty.channel.ChannelOperations.applyHandler(ChannelOperations.java:380)
	at reactor.ipc.netty.http.server.HttpServerOperations.onHandlerStart(HttpServerOperations.java:398)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:464)
	at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884)
	at java.lang.Thread.run(Thread.java:748)

[snicoll]

@madgnome thanks for the report but it would help to provide more details. Does it happen all the time? Is it broken on upgrade? A simple application we can run ourselves (link to a repo or zip) would be ideal.

[madgnome]

Only happened once so far just after startup.

Unfortunately I don't have a reproducible app, I assume it's a concurrency issue on initialization.

[snicoll]

That's interesting, looks like your heartbeat checks invoke the endpoint when it's not ready to process a request. That vaguely reminds me of something we fixed in the past.

Flagging for team attention.

[mbhave]

Possibly the same fix as #12380

[snicoll]

Potentially but not only. I'd like @wilkinsona to have a look as well.

[wilkinsona]

I agree with @mbhave's assessment. ApplicationContextServerWebExchangeMatcher needs to be updated to call initialized before assigning this.context and all of its subclasses need to be updated so that any fields that are assigned in initialized are volatile.