Request content preview isn't produced if decorate a service with `ThrottlingService`

I found that RequestLog#requestContentPreview returns null when I decorate a service using ContentPreviewingService and ThrottlingService.

The request content preview is not produced when aggregate a service which is decorated with following structure:

.decorator(((delegate, ctx, req) -> HttpResponse.from(
     completedFuture(null).handleAsync((ignored, cause) -> {
         try {
             return delegate.serve(ctx, req);
         } catch (Exception e) {
             return Exceptions.throwUnsafely(e);
         }
     }, ctx.eventLoop()))))

Following test can reproduce:

class RequestContentPreviewTest {

    private static final AtomicReference<ServiceRequestContext> ctxCaptor = new AtomicReference<>();

    @RegisterExtension
    static ServerExtension server = new ServerExtension() {
        @Override
        protected void configure(ServerBuilder builder) {
            builder.service("/", (ctx, req) -> {
                       ctxCaptor.set(ctx);
                       return HttpResponse.from(req.aggregate().thenApply(
                               aggregated -> HttpResponse.of("Hello, " + aggregated.contentUtf8() + "!")));
                   })
                   .decorator(LoggingService.builder()
                                            .requestLogLevel(LogLevel.INFO)
                                            .successfulResponseLogLevel(LogLevel.INFO)
                                            .failureResponseLogLevel(LogLevel.WARN)
                                            .newDecorator())
                   .decorator(ContentPreviewingService.newDecorator(Integer.MAX_VALUE))
                   .decorator(((delegate, ctx, req) -> HttpResponse.from(
                           completedFuture(null).handleAsync((ignored, cause) -> {
                               try {
                                   return delegate.serve(ctx, req);
                               } catch (Exception e) {
                                   return Exceptions.throwUnsafely(e);
                               }
                           }, ctx.eventLoop()))));
        }
    };

    @Test
    void requestContentPreviewH1C() {
        final WebClient client = WebClient.of(SessionProtocol.H1C,
                                              Endpoint.of("127.0.0.1", server.httpPort()));
        final RequestHeaders headers = RequestHeaders.of(HttpMethod.POST, "/",
                                                         HttpHeaderNames.CONTENT_TYPE, "text/plain");
        final AggregatedHttpResponse res = client.execute(headers, HttpData.ofUtf8("Armeria"))
                                                 .aggregate()
                                                 .join();
        assertThat(res.contentUtf8()).isEqualTo("Hello, Armeria!");

        final ServiceRequestContext ctx = ctxCaptor.get();
        final RequestLog log = ctx.log().whenComplete().join();
        assertThat(log.responseContentPreview()).isEqualTo("Hello, Armeria!");
        // expected: "Armeria"
        // but was: null
        // org.opentest4j.AssertionFailedError:
        // expected: "Hello, World!"
        assertThat(log.requestContentPreview()).isEqualTo("Armeria");
    }

    @Test
    void requestContentPreviewHTTP() {
        final WebClient client = WebClient.of(SessionProtocol.HTTP,
                                              Endpoint.of("127.0.0.1", server.httpPort()));
        final RequestHeaders headers = RequestHeaders.of(HttpMethod.POST, "/",
                                                         HttpHeaderNames.CONTENT_TYPE, "text/plain");
        final AggregatedHttpResponse res = client.execute(headers, HttpData.ofUtf8("Armeria"))
                                                 .aggregate()
                                                 .join();
        assertThat(res.contentUtf8()).isEqualTo("Hello, Armeria!");

        final ServiceRequestContext ctx = ctxCaptor.get();
        final RequestLog log = ctx.log().whenComplete().join();
        assertThat(log.responseContentPreview()).isEqualTo("Hello, Armeria!");
        assertThat(log.requestContentPreview()).isEqualTo("Armeria");
    }
}

logging H1C:

02:08:33.724 [armeria-common-worker-nio-2-2] INFO  c.l.a.server.logging.LoggingService - [sreqId=64b5968f, chanId=ec5eedd2, raddr=127.0.0.1:54446, laddr=127.0.0.1:54445][h1c://al01540922.local/#POST] Request: {startTime=2021-09-08T17:08:33.696Z(1631120913696000), length=7B, duration=24472µs(24472956ns), scheme=none+h1c, name=POST, headers=[:method=POST, :path=/, :scheme=http, host=127.0.0.1:54445, content-type=text/plain, user-agent=armeria/1.11.1-SNAPSHOT, content-length=7]}
02:08:33.741 [armeria-common-worker-nio-2-2] INFO  c.l.a.server.logging.LoggingService - [sreqId=64b5968f, chanId=ec5eedd2, raddr=127.0.0.1:54446, laddr=127.0.0.1:54445][h1c://al01540922.local/#POST] Response: {startTime=2021-09-08T17:08:33.737Z(1631120913737000), length=15B, duration=3305µs(3305059ns), totalDuration=43624µs(43624769ns), headers=[:status=200, content-type=text/plain; charset=utf-8, content-length=15], contentPreview=Hello, Armeria!}

logging H2C:

02:08:33.884 [armeria-common-worker-nio-2-4] INFO  c.l.a.server.logging.LoggingService - [sreqId=d4e30197, chanId=1d1d7144, raddr=127.0.0.1:54447, laddr=127.0.0.1:54445][h2c://al01540922.local/#POST] Request: {startTime=2021-09-08T17:08:33.882Z(1631120913882000), length=7B, duration=1976µs(1976048ns), scheme=none+h2c, name=POST, headers=[:method=POST, :path=/, :scheme=http, :authority=127.0.0.1:54445, content-type=text/plain, user-agent=armeria/1.11.1-SNAPSHOT, content-length=7], contentPreview=Armeria}
02:08:33.886 [armeria-common-worker-nio-2-4] INFO  c.l.a.server.logging.LoggingService - [sreqId=d4e30197, chanId=1d1d7144, raddr=127.0.0.1:54447, laddr=127.0.0.1:54445][h2c://al01540922.local/#POST] Response: {startTime=2021-09-08T17:08:33.884Z(1631120913884000), length=15B, duration=1648µs(1648011ns), totalDuration=3309µs(3309007ns), headers=[:status=200, content-type=text/plain; charset=utf-8, content-length=15], contentPreview=Hello, Armeria!}

It works well if not decorated by the last one.

What I found is that https://github.com/line/armeria/blob/dbc7d4d3a324aac525acbdce134fe56c34186a4f/core/src/main/java/com/linecorp/armeria/internal/logging/ContentPreviewingUtil.java#L62 is called before https://github.com/line/armeria/blob/dbc7d4d3a324aac525acbdce134fe56c34186a4f/core/src/main/java/com/linecorp/armeria/internal/logging/ContentPreviewingUtil.java#L82

And this is because a CloseEvent from Http1RequestDecoder is already in queue before collect.

[ghkim3221]

I think I was confused. Please ignore 😅

[ikhoon]

I found that when a HttpResponse is deferred, handleCloseEvent can be called before delegated service is served in HTTP/1. Maybe is it ok?

When I locally tested it, handleCloseEvent seems to be called by req.aggregate() in service. It should be a bug if handleCloseEvent is called before subscription.