Thank you! I was able to fix both of these issues. However, the fix for the issue #2 is hacky and I am sure there has to be a better way to fix this issue. Explained below.
On Wed, May 5, 2021 at 8:40 PM Maxim Dounin <mdou...@mdounin.ru> wrote: > Hello! > > On Wed, May 05, 2021 at 02:24:52PM -0700, Anatoliy Malishevskiy wrote: > > > I am trying to migrate from Apache2 to NGINX and having issues with SSE > > connections. Everything else is working fine, the regular GET or POST > > requests are getting through successfully. > > > > But there are 2 critical issues with SSE connections: > > 1) the NGINX holds up responses until the buffer is full > > 2) The NGINX blocks any other requests to the server if SSE is in > progress. > > > > With Apache2 I used to have issue #1, but it was easily resolved with the > > following configurations: > > - *OutputBufferSize 0* > > The issue #2 is really blocking me from using NGINX. Why does the server > > block > > other connections when SSE is in progress? > > How to fix this issue? > > [...] > > The "fastcgi_buffering off;" should be enough to disable response > buffering on nginx side. If it doesn't work for you, this means > one of the following: > > - You've not configured it properly: for example, configured it in > the wrong server block, or failed to reload configuration, or > not using fastcgi_pass to process particular requests. I think > this is unlikely, but you may want to double-check: for example, > by configuring something like "return 404;" in the relevant > location to see if it works. > > - Some buffering happens in your FastCGI backend. From your > configuration it looks like you are using fastcgiwrap, which > doesn't seem to provide any ways to flush libfcgi buffers, so > probably it is the culprit. > You were right pointing out to the fastcgiwrap, it was keeping buffers until the application is terminated or buffer is full. I fix this issue by adding the following lines into the /location: ### When set (e.g., to ""), disables output fastcgiwrap buffering. ### MUST be set if SEE used *fastcgi_param NO_BUFFERING "";* ### When buffering is disabled, the response is passed to a ### client synchronously, immediately as it is received. ### Nginx will not try to read the whole response from the ### FastCGI server. ### MUST be set if SEE used * fastcgi_buffering off;* > > Your other problem is likely also due to fastcgiwrap, but this > time incorrect configuration: by default it only provides one > process, so any in-progress request, such as server-sent events > connection, will block all other requests from being handled. You > have to configure more fcgiwrap processes using the "-c" command > line argument to handle multiple parallel requests. > You were right here. I had to provide the "-c4" parameter, for example, to fcgiwrap process. But I could not find an easy way to set this parameter, I had to hack /etc/init.d/fcgiwrap and change DAEMON_OPTS variable and force the script to stop then start the service again with new parameters when I type: > sudo /etc/init.d/fcgiwrap reload Do you know any better way to provide this -c4 parameter to fcgiwrap? Or I have to create my own fcgiwrap script just only to enable multiple parallel requests handling? Thanks > > -- > Maxim Dounin > http://mdounin.ru/ > _______________________________________________ > nginx mailing list > nginx@nginx.org > http://mailman.nginx.org/mailman/listinfo/nginx > -- Anatoliy Malishevskiy YumaWorks, Inc.
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