Running a flask app with nginx and gunicorn


I'm new at this and have only been using nginx to serve static files. I have now installed flask and gunicorn. If I run gunicorn -b hello:app and then wget it from the server it works well. If I try to access it from a browser, however, it returns a 404 error (I am running this on a server that hosts a wordpress site which is locatet at root).

The flask app:

from flask import Flask
from werkzeug.contrib.fixers import ProxyFix
app = Flask(__name__)

def hello():
    return "Hello world!"

app.wsgi_app = ProxyFix(app.wsgi_app)

if __name__ == '__main__':

And the relevant part of my nginx configuration:

location /flask {
                 proxy_set_header       Host            $http_host;
                 proxy_set_header       X-Real-IP       $remote_addr;
                 proxy_set_header       X-Forwarded-For $proxy_add_x_forwarded_\
                 proxy_pass   ;
                 proxy_redirect         off;

I hope this is all the relevant info. If not, do tell. Thanks!

3/18/2013 10:40:33 PM

Accepted Answer

This is how I serve my flask apps in Nginx:

Run gunicorn daemonized using a socket:

  sudo gunicorn app:app --bind unix:/tmp/gunicorn_flask.sock -w 4 -D

Related nginx config:

    upstream flask_server {
        # swap the commented lines below to switch between socket and port
        server unix:/tmp/gunicorn_flask.sock fail_timeout=0;
        #server fail_timeout=0;
    server {
        listen 80;
        return 301 $scheme://$request_uri;

    server {
        listen 80;
        client_max_body_size 4G;

        keepalive_timeout 5;

        # path for static files
        location  /static {
            alias /path/to/static;
            autoindex on;
            expires max;

        location / {
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Host $http_host;
            proxy_redirect off;

            if (!-f $request_filename) {
                proxy_pass http://flask_server;

12/1/2012 5:11:46 PM

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