Have armeria always add a fallback Service for not found requests?

I found in https://github.com/openzipkin/zipkin/pull/2348 that there is somewhat confusing behavior regarding ServerBuilder.decorator - as it only decorates mapped services, requests that aren’t mapped and returned as NOT_FOUND are not handled by the decorator. If the decorator is for metrics collection, and has logic for not found requests, it doesn’t work.

Does it make sense to have armeria always add a service at the end for not_found requests to make sure behavior is consistent with mapped requests?

[trustin]

WRT custom status rendering, here, we could translate an HttpStatusException into an HttpResponse using a Function<HttpStatusException, HttpResponse>.

The 404-responding service could raise HttpStatusException.of(404) to take advantage of this feature.

[trustin]

The proposal intends to provide a universal way to handle both 404 and HttpStatusException, but I found that 404 and HttpStatusException are different; If HttpStatusException is raised, it means the service has been invoked already, so issuing another request will create an extra request log.

So… let me drop the proposal and just make the following changes:

• Modify ServerBuilder and VirtualHostBuilder so that a 404-responding service is bound automatically at prefix:/ as the last service, if not duplicate.