HTTP-Adapter: IllegalStateException: Response has already been written

The HTTP adapter showed this error in the logs:

DEBUG VertxBasedHttpProtocolAdapter  failed to send http response for [EVENT] message from device [tenantId: test, deviceId: test_123]: response already closed
WARN  JaegerSpan  Span has already been finished; will not be reported again.
WARN  TracingHelper  An unexpected error occurred!
java.lang.IllegalStateException: Response has already been written
	at io.vertx.core.http.impl.Http1xServerResponse.end(Http1xServerResponse.java:394)
	at io.vertx.core.http.impl.Http1xServerResponse.end(Http1xServerResponse.java:382)
	at io.vertx.core.http.impl.Http1xServerResponse.end(Http1xServerResponse.java:451)
	at org.eclipse.hono.adapter.http.AbstractVertxBasedHttpProtocolAdapter.lambda$doUploadMessage$31(AbstractVertxBasedHttpProtocolAdapter.java:738)

[calohmn]

Hi, I tried to reproduce it by adding to the request the following property hono-ttd (CASE 1) and I canceled the request before the hono-ttd expires, the result is that it does not enter into Line: 699 (.map(proceed -> {…)

So that means that the Future result from the preceding compose block isn’t getting succeeded. In fact, since the recover block below apparently isn’t entered as well (no cannot process message in your logs above), this Future isn’t completed at all, if the hono-ttd request is cancelled by the device.

I would have guessed that this could mean a memory leak, but according to some tests I’ve done here this doesn’t seem to be the case. Nonetheless I think this is something that should be corrected, letting the Future be completed when the request gets closed by the device prematurely.

In any case, the above tests seem to show that reproducing the error described in this issue isn’t that easy. My guess here would be that you would need to send a hono-ttd request and actually send a command message in response to that and then, while this block https://github.com/eclipse/hono/blob/5a3ae23bb73be5a5d123eba7f43447a0b6c7c58e/adapters/http-base/src/main/java/org/eclipse/hono/adapter/http/AbstractVertxBasedHttpProtocolAdapter.java#L685-L694 is being processed (i.e. while an unregister-cmd-consumer request is sent to the Command Router), the client has to cancel the request. In order to achieve this, it could help to add some delay (in the form of a vert.x timer execution) in the above block when testing this.

[sophokles73]

Sure 😃