# Python wsgi behind nginx: yield not behaving as expected **URL:** \ **Category:** NGINX\ **Created:** [November 3, 2011, 8:09am UTC](https://www.ruby-forum.com/t/python-wsgi-behind-nginx-yield-not-behaving-as-expected/213477 "2011-11-03T08:09:31Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![dubstep](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/cdc98d/32.png) [@dubstep](https://www.ruby-forum.com/u/dubstep)\ **Post date:** [November 3, 2011, 8:09am UTC](https://www.ruby-forum.com/t/python-wsgi-behind-nginx-yield-not-behaving-as-expected/213477/1 "2011-11-03T08:09:31Z")
Hi, I want to run wsgi python code on a web server behind nginx. The server needs to respond quickly to an http request, then continue to do some (slow) work after responding. Python’s yield statement seems to fit the bill, as follows: def application(environ, start\_response): output = get\_response\_quickly(environ) start\_response(‘200 OK’,[(‘Content-type’, ‘text/plain’),(‘Content-Length’, str(len(output)))]) yield output do\_slow\_work() If I run this wsgi in a standalone python server (I tried wsgiref, fapws, uwsgi), the caller receives the output immediately (after get\_response\_quickly()), as desired. Great. However, if I run any of these servers behind nginx, the caller doesn’t receive a response until _after_ do\_slow\_work() – thus defeating the purpose. Is there a way to make this pattern work with nginx? Or is there a better way in general to respond quickly but continue work, without manually creating python threads / other clumsiness? Thanks, Matt ---
**Author:** ![Matt\_Starcrest](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/dbc845/32.png) [@Matt\_Starcrest](https://www.ruby-forum.com/u/Matt_Starcrest)\ **Post date:** [November 3, 2011, 8:13am UTC](https://www.ruby-forum.com/t/python-wsgi-behind-nginx-yield-not-behaving-as-expected/213477/2 "2011-11-03T08:13:13Z")
On Thu, Nov 03, 2011 at 12:08:49AM -0700, Matt Starcrest wrote: > If I run this wsgi in a standalone python server (I tried wsgiref, fapws, > uwsgi), the caller receives the output immediately (after get\_response\_quickly()), > as desired. Great. However, if I run any of these servers behind nginx, the caller > doesn’t receive a response until _after_ do\_slow\_work() – thus defeating the > purpose. > > Is there a way to make this pattern work with nginx? Or is there a better way in > general to respond quickly but continue work, without manually creating python > threads / other clumsiness? In nginx-1.0.9 or nginx-1.1.5 you can try uwsgi\_buffering off; or sgi\_buffering off; depending on protocol. In any modern enough nginx version you can use proxy\_buffering off; There is no way currently to disable buffering of FastCGI servers. – Igor S. ---
**Author:** ![Matt\_Starcrest](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/dbc845/32.png) [@Matt\_Starcrest](https://www.ruby-forum.com/u/Matt_Starcrest)\ **Post date:** [November 3, 2011, 8:49am UTC](https://www.ruby-forum.com/t/python-wsgi-behind-nginx-yield-not-behaving-as-expected/213477/3 "2011-11-03T08:49:01Z")
Looks like that solved it! Thanks Igor! * * * From: Igor S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) To: [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) Sent: Thursday, November 3, 2011 12:12 AM Subject: Re: python wsgi behind nginx: yield not behaving as expected On Thu, Nov 03, 2011 at 12:08:49AM -0700, Matt Starcrest wrote: > If I run this wsgi in a standalone python server (I tried wsgiref, fapws, > uwsgi), the caller receives the output immediately (after get\_response\_quickly()), > as desired. Great. However, if I run any of these servers behind nginx, the caller > doesn’t receive a response until _after_ do\_slow\_work() – thus defeating the > purpose. > > Is there a way to make this pattern work with nginx? Or is there a better way in > general to respond quickly but continue work, without manually creating python > threads / other clumsiness? In nginx-1.0.9 or nginx-1.1.5 you can try uwsgi\_buffering off; or sgi\_buffering off; depending on protocol. In any modern enough nginx version you can use proxy\_buffering off; There is no way currently to disable buffering of FastCGI servers. – Igor S. ---
**Author:** ![Matt\_Starcrest](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/dbc845/32.png) [@Matt\_Starcrest](https://www.ruby-forum.com/u/Matt_Starcrest)\ **Post date:** [November 3, 2011, 8:52am UTC](https://www.ruby-forum.com/t/python-wsgi-behind-nginx-yield-not-behaving-as-expected/213477/4 "2011-11-03T08:52:06Z")
On Thu, Nov 03, 2011 at 12:48:30AM -0700, Matt Starcrest wrote: > Looks like that solved it! Thanks Igor! Please note, that any “…\_buffering off” disables caching, so you can set it exactly on locations which should be cached: location /some/page { …\_buffering off; } > > output = get\_response\_quickly(environ) > > In nginx-1.0.9 or nginx-1.1.5 you can try > > Igor S. > > * * * > > nginx mailing list > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [mailman.nginx.org archive](http://mailman.nginx.org/mailman/listinfo/nginx) > * * * > > nginx mailing list > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > [mailman.nginx.org archive](http://mailman.nginx.org/mailman/listinfo/nginx) – Igor S.