nginx uwsgi websockets 502 Bad Gateway upstream prematurely closed connection while reading response header from upstream

Question

I\'ve been banging my head on this issue for days now and have finally reached a brick wall.

I\'ve been trying to get my stack to run:

http://django-websock

Answer 1

I found the issue.

My [runserver] socket (app.sock) should be pointed under upstream django and my [wsserver] socket (django.sock) should be pointed under location /ws/ like so:

upstream django {
    server unix:/opt/django/app.sock;
}

server {
    listen 80 default_server;
    charset utf-8;
    client_max_body_size 20M;
    sendfile on;
    keepalive_timeout 0;
    large_client_header_buffers 8 32k;

location /media  {
    alias /opt/django/app/media/media;  
}

location /static {
    alias /opt/django/app/static;
}

location / {
    include /opt/django/uwsgi_params; 
}

location /ws/ {
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_pass http://unix:/opt/django/django.sock;
        proxy_buffers 8 32k;
        proxy_buffer_size 64k;
    }
}

Answer 2

I had same issue but it wasn't my NGINX configuration, it was my UWSGI processes causing timeout errors when I posted JSONs from client side to server. I had processes as 5, I changed it to 1 and it solved the issue. For my application, I only needed to have 1 process run at time since AWS didn't need to be overloaded with multiple processes.

Here is the working UWSGI configuration ini file that solved the timeout issue and thus the 502 gateway issue.

autoboot.ini

#!/bin/bash

[uwsgi]
socket          = /tmp/app.sock

master          = true

chmod-socket    = 660
module          = app.wsgi
chdir           = home/app

close-on-exec = true # Allow linux shell via uWSGI

processes = 1
threads = 2
vacuum = true

die-on-term = true

Here's my nginx config too.

nginx.conf

# the upstream component nginx needs to connect to
upstream django {
    server unix:///app/tmp/app.sock; # for a file socket
    # server 127.0.0.1:6000; # for a web port socket (we'll use this first)
}

# configuration of the server
server {
    # the port your site will be served on
    listen      80;

    # the domain name it will serve for
    server_name XXX.XXX.XX.X #actual IP in here
    charset     utf-8;

    # max upload size
    client_max_body_size 75M;   # adjust to taste

    error_log /var/log/nginx/error.log;
    access_log /var/log/nginx/access.log;

    # Finally, send all non-media requests to the Django server.
    location / {
        uwsgi_pass  django;
        include     uwsgi_params;
    }

    location /static {
        autoindex on;
        alias app/static; # your Django project's static files - amend as required
    }

    error_page 502 /502.html;
    location = /502.html {
        alias app/templates/502autoreload.html;
    }

    client_body_timeout 100s;
    uwsgi_read_timeout 500s;
    keepalive_timeout 300;
}