Running a proxy_pass on a subpath in NGINX - sockets

Question

I am trying to run a Flask app on Gunicorn through an Nginx server. I would like the app to run on a sub-directory instead of through a different port, if possible, but all I get are 404 errors. Here is my conf file, which is an included file in the conf.d folder:
server {
listen 80;
server_name 127.0.0.1;
location / {
root /var/www/html;
}
location /chess/ {
proxy_pass http://unix:/usr/share/nginx/sockets/chess.sock;
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
}
}
Could someone please tell me how to do this? I have looked all over and tried a lot of different things, to no avail. It runs fine on a different port, but that is not what I want. A subdomain is also a suitable option, but I can only get that to work in production, not development, for some reason. Someone posed the question here but the link they gave to the solution is dead.

Answer 1

when do you get 404's? when you access /chess/?
please attach the flask app's code.
anyway,
the following certainly works, I tested it.
followed this guide
myproject.py:
from flask import Flask
app = Flask(__name__)
#app.route("/chess/",defaults={'name': None})
#app.route("/chess/<name>")
def hello(name):
if name is None:
name="!"
else:
name = ", " + name
# PLEASE don't use the following line of code in a real app, it creates a self-xss vulnerability. ALWAYS sanitize user input.
return f"<h1 style='color:blue'>Hello There{name}</h1>"
if __name__ == "__main__":
app.run(host='0.0.0.0')
nginx - /etc/nginx/sites-enabled/myproject (symlink)
server {
listen 8080;
server_name your_domain www.your_domain;
location / {
root /home/username/myproject/static/;
}
location /chess/ {
include proxy_params;
proxy_pass http://unix:/home/username/myproject/myproject.sock;
}
}
<host>:8080/chess/stackoverflow:
<host>:8080/a.html: (actually served from /home/myproject/static)
generally and for future reference - try looking at nginx logs (/var/log/nginx) or service logs (journalctl -u myproject or systemctl status myproject)

Answer 2

Two methods are available. The first method involves adding the subpath to both the NGINX configuration and the Flask app, as suggested in the answer by Yarin_007. Set up NGINX like so:
server {
listen localhost:80;
location / {
root /var/www/html;
}
location /chess/ {
proxy_pass http://unix:/usr/share/nginx/sockets/chess.sock;
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
}
}
And alter the Flask app to include the subpath:
from flask import Flask, request
...
#app.route("/chess/", methods=["GET", "POST"])
...
The alternative, as suggested in this answer is to run the Gunicorn service on a non-privileged port (or maybe a subdomain) and use two proxy_pass directives to direct from the port 80 subpath like so:
server {
listen localhost:80;
location / {
root /var/www/html;
}
location /chess/ {
proxy_pass http://localhost:8080/;
}
}
server {
listen localhost:8080;
location / {
proxy_pass http://unix:/usr/share/nginx/sockets/chess.sock;
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
}
}
The Flask app can remain as it was originally:
from flask import Flask, request
...
#app.route("/", methods=["GET", "POST"])
...