asynchronous handler support

[mxx]

ring support asynchronous handler,
and undertow also support asynchronous process
it seems luminus do not.
or maybe I misunderstand something.

[yogthos]

I'm not sure what you mean here. You can use async Ring handlers in Luminus out of the box. The async functionality is handled by Ring and Compojure libraries.

[poernahi]

I was experimenting with async handlers and come across this issue. It looks like the immutant adapter is synchronous if used as-is, and assumes 1 arg handler function. Supplying a 3 arg async handler will cause ArityException.

Example implementation: ring-jetty-adapter accepts an additional :async? option which wraps the async handler in an AsyncContext.

I'm not sure yet how to do this on top of immutant as the API is rather different.

Another thing to note when using luminus, is that most of the middlewares in the template only support single arity.

I'm not sure if this is worth doing yet, as the current blocking handler has been more than good enough for many use case. Would like to know your thoughts.

[yogthos]

I actually haven't run into a situation where I needed to use the async handlers myself. I find the sync handlers are performant enough even for high loads. Note that the sync handlers don't block either until the thread pool is exhausted. Immutant uses a dedicated thread to accept connections, and then passes the actual request handling off to a thread pool of workers.