Apache HTTP Client interceptor for use with HttpAsyncClient

[candresrv]

Hi there, I see there is a Micrometer implementation to track the time that http requests take using MicrometerHttpRequestExecutor, but in my project I'm executing these requests using CloseableHttpAsyncClient:

i.e. : myCloseableHttpAsyncClient.execute(req, cxt, callback);

Where:

• req is an HttpUriRequest obj
• cxt is a HttpClientContext obj

Is there any way to use Micrometer under this implementation?

Thanks!

[jkschneider]

@candresrv Hopefully the method provided below will work for you with the new MicrometerHttpClientInterceptor. Please try out the 1.4.0 snapshot if you get a chance, as this release will be coming out soon.

CloseableHttpAsyncClient asyncClient() {
    MicrometerHttpClientInterceptor interceptor = new MicrometerHttpClientInterceptor(registry,
            request -> request.getRequestLine().getUri(),
            Tags.empty(),
            true);

    return HttpAsyncClients.custom()
            .addInterceptorFirst(interceptor.getRequestInterceptor())
            .addInterceptorLast(interceptor.getResponseInterceptor())
            .build();
}

[flozano]

One question - why is not the Timer.ResourceSample stored directly inside the HttpContext instead of a ConcurrentMap in the MicrometerHttpClientInterceptor?

I am having unexpected behaviours; my interceptors are properly configured (visualVM snapshot of the actual running code):

but then sometimes I get:

java.lang.NullPointerException: Cannot invoke "io.micrometer.core.instrument.Timer$ResourceSample.tag(String, String)" because the return value of "java.util.Map.remove(Object)" is null
	at io.micrometer.core.instrument.binder.httpcomponents.MicrometerHttpClientInterceptor.lambda$new$1(MicrometerHttpClientInterceptor.java:75)
	at org.apache.http.protocol.ImmutableHttpProcessor.process(ImmutableHttpProcessor.java:142)
	at org.apache.http.impl.nio.client.MainClientExec.responseReceived(MainClientExec.java:290)
	at org.apache.http.impl.nio.client.DefaultClientExchangeHandlerImpl.responseReceived(DefaultClientExchangeHandlerImpl.java:152)
	at org.apache.http.nio.protocol.HttpAsyncRequestExecutor.responseReceived(HttpAsyncRequestExecutor.java:315)
	at org.apache.http.impl.nio.DefaultNHttpClientConnection.consumeInput(DefaultNHttpClientConnection.java:255)
	at org.apache.http.impl.nio.client.InternalIODispatch.onInputReady(InternalIODispatch.java:87)
	at org.apache.http.impl.nio.client.InternalIODispatch.onInputReady(InternalIODispatch.java:40)
	at org.apache.http.impl.nio.reactor.AbstractIODispatch.inputReady(AbstractIODispatch.java:121)
	at org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:162)
	at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:337)
	at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:315)
	at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:276)
	at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:104)
	at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:591)
	at java.base/java.lang.Thread.run(Thread.java:833)

which basically means that the HttpContext is not found in the map.

While troubleshooting this I was thinking to rewrite using the HttpContext as the holder of the timer, and I was wondering why this approach was taken instead.