Only one connection receive subscriber allowed with Content-Type application/x-www-form-urlencoded

[dave-fl]

Running on SR1.Finchley.

When the Gateway is under load I am seeing this occasionally. We are not doing anything where we are trying to intercept the response body.

2018-09-11T13:01:39.71-0400 [APP/PROC/WEB/0] OUT 2018-09-11 17:01:39.717 ERROR 14 --- [client-epoll-19] .a.w.r.e.DefaultErrorWebExceptionHandler : Failed to handle request [POST ]
2018-09-11T13:01:39.71-0400 [APP/PROC/WEB/0] OUT java.lang.IllegalStateException: Only one connection receive subscriber allowed.
2018-09-11T13:01:39.71-0400 [APP/PROC/WEB/0] OUT     at reactor.ipc.netty.channel.FluxReceive.startReceiver(FluxReceive.java:276) ~[reactor-netty-0.7.8.RELEASE.jar!/:0.7.8.RELEASE]
2018-09-11T13:01:39.71-0400 [APP/PROC/WEB/0] OUT     at reactor.ipc.netty.channel.FluxReceive.lambda$subscribe$2(FluxReceive.java:127) ~[reactor-netty-0.7.8.RELEASE.jar!/:0.7.8.RELEASE]
2018-09-11T13:01:39.71-0400 [APP/PROC/WEB/0] OUT     at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163) ~[netty-common-4.1.27.Final.jar!/:4.1.27.Final]
2018-09-11T13:01:39.71-0400 [APP/PROC/WEB/0] OUT     at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404) ~[netty-common-4.1.27.Final.jar!/:4.1.27.Final]
2018-09-11T13:01:39.71-0400 [APP/PROC/WEB/0] OUT     at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:322) ~[netty-transport-native-epoll-4.1.27.Final-linux-x86_64.jar!/:4.1.27.Final]
2018-09-11T13:01:39.71-0400 [APP/PROC/WEB/0] OUT     at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884) ~[netty-common-4.1.27.Final.jar!/:4.1.27.Final]
2018-09-11T13:01:39.71-0400 [APP/PROC/WEB/0] OUT     at java.lang.Thread.run(Thread.java:748) ~[na:1.8.0_172]

Only using retry and rewrite path filter + custom filter which populates headers and sets path.

[spencergibb]

Not much to go on. Doesn't look like it has anything specific to do with the gateway.

[canglang1973]

I also meet this question, if I use GET method ,I can request success.but I use POST method ,we will see this
exception like the first man's comment. My request params like KEY-VALUES. Who can fix this problem?

[dave-fl]

@canglang1973 Are you able to create a simple test scenario or does it only happen after a while or under load?

[spencergibb]

cc @violetagg

[violetagg]

Works by design
reactor/reactor-netty#247

[dave-fl]

@violetagg @spencergibb
Spencer says not a gateway issue, Violetagg says not a Reactor Issue.

For whatever reason there appears at least in my testing that somehow POST bodies are being read by the gateway twice (or they are being put back into the pool with an invalid state).

[dave-fl]

@canglang1973 Using a simple test of having a query parameter + POST is not enough for me to reproduce the error.

[canglang1973]

` @bean
public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
return builder.routes()
.route(r -> r.path("/router/rest")
.uri("http://127.0.0.1:8084")
).build();
}
This is my simple test ,not have other filters ,@dave-fl``` Have you solved this problem?Can you tell me your solution?

[canglang1973]

@spencergibb you can give me a simple test can support POST ,I think spring cloud gateway impossible not support POST method.

[spencergibb]

@violetagg in all these cases, the body isn't being read twice.

[spencergibb]

@canglang1973 we can't reproduce it

[canglang1973]

@spencergibb I used spring cloud gateway version is 2.0.1.RELEASE ,spring boot version is 2.0.5.RELEASE ,jdk is 1.8 .The point is I don't have user-defined filters .

[canglang1973]

I see all the issues ,man people meet this same question but nobody fix

[spencergibb]

@canglang1973 provide a project that recreates the problem and steps to reproduce it. It should be something we can clone or download.