Ubuntu 16.04 Gunicorn, Flask, WSGI 502 Gateway Error

September 12, 2016 1.3k views
Deployment Ubuntu 16.04

Hi Everyone! I’m using this to deploy my flask app. However I’m running into a 502 Gateway Error. I have looked at several posts, and I have not found a solution.

I have already added the extra slashes in the .ini file:

proxy_pass http://unix:///home/sammy/myproject/myproject.sock;

and that didn’t work. After checking the error logs, we found that we’re getting a
“upstream prematurely closed connection while reading response header from upstream client”. We’re guessing that we need to increase the timeout, but that didn’t work for us.

Any help would be appreciated!

1 Answer

proxy_pass http://unix:///home/sammy/myproject/myproject.sock; most likely is not what you intended here. It includes both a http:// and unix:// protocol and should have one or the other. To use a unix socket file as the upstream source you should update this line to read:

proxy_pass unix:///home/sammy/myproject/myproject.sock;
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