> Hi, > > Help me wrap my head around async implementation in uwsgi. I come from > perl > world and use psgi, coroae and really enjoy uwsgi. Great thing you wrote. > > My problem is that Coro is an overkill for me as my programs mostly > AnyEvent (AE) based and I don't use coroutines to full power. Also, we > have > problems restarting uwsgi as Coro seg faults during perl's global > destruction in our setup. In recently written service this cause a lot of > pain as our worker spawns a child and due to seg fault has no chance to > cleanup the child, what prevents uwsgi to start again. > > I wonder if it's possible to get rid of Coro and implement a plugin that > would allow us to write async psgi applications using AnyEvent. > > Spent some time in uwsgi's code and from what I can see uwsgi's async > implementation is a combination of co-routines and event loop. async > option > allocates N "cores" within a worker to handle N requests simultaneously. > uGreen (co-routines) plugin implements uwsgi's context switches between > these N "cores" by providing operations to suspend/resume a "core". uGreen > also calls suspend/resume hooks in the request handler plugin if provided, > in my case it would probably be psgi plugin or my custom. > > Open question: > * can I write such plugin that works without co-routines in perl world? > * how does event loop fits into uwsgi's async world? > >
Hi, your analysis is correct, the internal core expects some kind of stack switching features (that basically is what causes your headaches ;) As technologies like asyncio are becoming a standard, in latest 2.0 versions the 'worker override feature has been added': http://uwsgi-docs.readthedocs.io/en/latest/WorkerOverride.html Basically you can write your worker core in the native language (perl+AnyEvent in your case) to support more paradigms. The perl plugin currently lacks the .worker hook: https://github.com/unbit/uwsgi/blob/master/plugins/python/python_plugin.c#L2070 but is super easy to add: https://github.com/unbit/uwsgi/blob/master/plugins/python/python_plugin.c#L2003 basically that function runs your perl loop in the worker process address space, so all the uwsgi api is supported. So, you need three steps: - implement the .worker hook - implement the uwsgi.accepting() api func (if you plan to support chain-reloading) - implement the perl script that cooperate with AnyEvent Take in account that i would absolutely merge such a patch in the stable branch :) -- Roberto De Ioris http://unbit.com _______________________________________________ uWSGI mailing list uWSGI@lists.unbit.it http://lists.unbit.it/cgi-bin/mailman/listinfo/uwsgi
