NPE at HttpClientOperations.isWebsocket

[lhotari]

Expected behavior

Calling HttpClientOperations.isWebsocket shouldn't throw a NPE.

Actual behavior

NPE gets thrown in some cases:

java.lang.NullPointerException: null
	at reactor.ipc.netty.http.client.HttpClientOperations.isWebsocket(HttpClientOperations.java:325) ~[reactor-netty-0.7.7.BUILD-SNAPSHOT.jar!/:0.7.7.BUILD-SNAPSHOT]
	at reactor.ipc.netty.http.client.HttpClientOperations.onOutboundComplete(HttpClientOperations.java:506) ~[reactor-netty-0.7.7.BUILD-SNAPSHOT.jar!/:0.7.7.BUILD-SNAPSHOT]
	at reactor.ipc.netty.channel.ChannelOperations.onComplete(ChannelOperations.java:219) ~[reactor-netty-0.7.7.BUILD-SNAPSHOT.jar!/:0.7.7.BUILD-SNAPSHOT]
	at reactor.core.publisher.Operators$MonoSubscriber.onComplete(Operators.java:1111) ~[reactor-core-3.1.7.BUILD-SNAPSHOT.jar!/:3.1.7.BUILD-SNAPSHOT]
	at reactor.core.publisher.MonoIgnoreThen$ThenAcceptInner.onComplete(MonoIgnoreThen.java:308) ~[reactor-core-3.1.7.BUILD-SNAPSHOT.jar!/:3.1.7.BUILD-SNAPSHOT]
	at reactor.ipc.netty.FutureMono$ChannelFutureSubscription.setSuccess(FutureMono.java:367) ~[reactor-netty-0.7.7.BUILD-SNAPSHOT.jar!/:0.7.7.BUILD-SNAPSHOT]
	at io.netty.channel.DefaultChannelPromise.setSuccess(DefaultChannelPromise.java:73) ~[netty-transport-4.1.24.Final.jar!/:4.1.24.Final]
	at reactor.ipc.netty.channel.ChannelOperationsHandler$PublisherSender.onComplete(ChannelOperationsHandler.java:583) ~[reactor-netty-0.7.7.BUILD-SNAPSHOT.jar!/:0.7.7.BUILD-SNAPSHOT]
	at reactor.core.publisher.FluxMap$MapSubscriber.onComplete(FluxMap.java:130) ~[reactor-core-3.1.7.BUILD-SNAPSHOT.jar!/:3.1.7.BUILD-SNAPSHOT]
	at reactor.core.publisher.FluxMap$MapSubscriber.onComplete(FluxMap.java:130) ~[reactor-core-3.1.7.BUILD-SNAPSHOT.jar!/:3.1.7.BUILD-SNAPSHOT]
	at reactor.core.publisher.FluxPeek$PeekSubscriber.onComplete(FluxPeek.java:245) ~[reactor-core-3.1.7.BUILD-SNAPSHOT.jar!/:3.1.7.BUILD-SNAPSHOT]
	at reactor.core.publisher.FluxMap$MapSubscriber.onComplete(FluxMap.java:130) ~[reactor-core-3.1.7.BUILD-SNAPSHOT.jar!/:3.1.7.BUILD-SNAPSHOT]
	at reactor.core.publisher.Operators.complete(Operators.java:125) ~[reactor-core-3.1.7.BUILD-SNAPSHOT.jar!/:3.1.7.BUILD-SNAPSHOT]
	at reactor.ipc.netty.channel.FluxReceive.startReceiver(FluxReceive.java:267) ~[reactor-netty-0.7.7.BUILD-SNAPSHOT.jar!/:0.7.7.BUILD-SNAPSHOT]
	at reactor.ipc.netty.channel.FluxReceive.lambda$subscribe$2(FluxReceive.java:127) ~[reactor-netty-0.7.7.BUILD-SNAPSHOT.jar!/:0.7.7.BUILD-SNAPSHOT]
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163) ~[netty-common-4.1.24.Final.jar!/:4.1.24.Final]
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404) [netty-common-4.1.24.Final.jar!/:4.1.24.Final]
	at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:309) [netty-transport-native-epoll-4.1.24.Final-linux-x86_64.jar!/:4.1.24.Final]
	at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884) [netty-common-4.1.24.Final.jar!/:4.1.24.Final]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_152]

Steps to reproduce

Reproducing the issue might be hard. I did this to get the error, the error appeared in the gateway logs:

git clone https://github.com/lhotari/spring-cloud-gw-issue-228
cd spring-cloud-gw-issue-228
mvn package
# terminal 1
java -jar apigw-test-ms/target/apigw-test-ms-exec.jar
# terminal 2
java -Dspring.cloud.gateway.httpclient.pool.type=DISABLED -jar gateway/target/gateway-0.0.1-SNAPSHOT.jar
# terminal 3
java -jar test-driver/target/test-driver-1.0.0.jar

I was able to reproduce the issue twice. On the first time, it took about 2 minutes to reproduce and on the second time, it took over 7 minutes to reproduce.

Reactor Netty version

0.7.7.BUILD-SNAPSHOT (ac103c0)

JVM version (e.g. java -version)

openjdk version "1.8.0_152"
OpenJDK Runtime Environment (Zulu 8.25.0.1-linux64) (build 1.8.0_152-b16)
OpenJDK 64-Bit Server VM (Zulu 8.25.0.1-linux64) (build 25.152-b16, mixed mode)

OS version (e.g. uname -a)

Linux 4.13.0-39-generic #44~16.04.1-Ubuntu

[violetagg]

java -Dspring.cloud.gateway.httpclient.pool.type=DISABLED -jar gateway/target/gateway-0.0.1-SNAPSHOT.jar

@lhotari just to clarify that we need to disable the pool in order to reproduce the issue. Is that correct?

[lhotari]

@violetagg yes, that's the case.

[violetagg]

@lhotari can you try this fix #343. I think that NPE is just a side effect of #323

[lhotari]

@violetagg I tested with the issue-323 branch (dac97b5). The NPE still occurs with that change.

[violetagg]

@lhotari ok the cause is still the same #323 but we need that check for NULL also. Please try the new version of the change.

Thanks a lot

[lhotari]

@violetagg yes, that fixed the NPE. Thank you

[violetagg]

fixed by 4a2e773

thanks for testing