[undertow-dev] Undertow Request Lifecycle

I hate asking generic questions, but I'm looking for a little understanding or clarification on request lifecycles. If you haven't noticed, I've had several recent threads that touch on this. Before anyone asks, - Yes, I have read all the docs I can find on this Ex http://undertow.io/undertow-docs/undertow-docs-2.0.0/undertow-request-lif... http://undertow.io/undertow-docs/undertow-docs-2.0.0/#listeners-2 http://undertow.io/undertow-docs/undertow-docs-2.0.0/servlet-using-non-bl... - Yes, I have Google and read 3rd party docs and guides on Undertow. Ex: https://www.oreilly.com/library/view/jboss-developers-guide/9781788296199... - Yes, I have spent hours reviewing the code and experimenting I've learned a lot, but there's a couple elusive things that all the docs and guides I see don't quite seem to satisfactorily explain for me. I'm trying to get some clarification on exactly what part of the request happens inside the xnio worker thread and which part runs inside the ThreadPoolExecutor. My server bootstrap wraps a number of various HttpHandlers around the handler that I set into the server builder and I had originally assumed that those handlers were part of the same handler chain that invoked the servlet. This appears to not be the case. The handler chain I pass to the server builder appears to execute as part of the org.xnio.nio.WorkerThread.run() thread, while my servlet code executes inside a thread pool executor. Both stack traces show that there is a chain of handler.handleRequest() calls, but this duality causes some confusion and troubles for me. It also seems to explain to an extent why Stuart's previous messages treated the "servlet" as a concept so far removed from the initial handler chain. Even docs like the last link I provided above that contain this image... [image: image.png] make it sound like there is a single "root handler". However, *executeRootHandler* appears in the stack traces of both the XNIO worker as well as during the servlet chain in the thread pool executor. at at This has proved to create difficulty in trying to accomplish seemingly very simple tasks with Undertow. For example, an example I gave in a previous thread was a simple task of logging every HTTP request that returned a non-successful status code. Seems easy enough, right? However... - I can't use an exchange complete listener because it doesn't fire with handlers like *response-code* that end the exchange - I can't wrap the servlet handler chain because that chain is never invoked if the exchange is ended first by my predicates - I can't wrap the handler chain being run in the XNIO listener because it doesn't wrap the servlet chain so my "before" and "after" code all runs before the servlet chain starts. I would love any help and insight both on my general question for documentation regarding the two separate handler chains as well as my more specific question above about implementing something as simple as a handler/listener that always runs at the end of an exchange. Thanks! ~Brad *Developer Advocate* *Ortus Solutions, Corp * E-mail: brad(a)coldbox.org ColdBox Platform: http://www.coldbox.org Blog: http://www.codersrevolution.com