Flask + Gunicorn + Nginx, 404 error using proxy_pass from non-root location block

Question

I would like to take some user input, run a few lines of Python, and display the results on the web.

I have a domain pointed to a server on DigitalOcean, and am following this tutorial: https://www.digitalocean.com/community/tutorials/how-to-serve-flask-applications-with-gunicorn-and-nginx-on-ubuntu-18-04

I've been able to get through the tutorial and it does work, however I'd of course like for my site not to be completely overridden by the phrase "Hello there!". I would like to display the results at a non-root location such as https://example.com/myproject/.

The domain I have has already been secured using Let's Encrypt & CertBot.

I am using a single nginx config file called default - the rest of the tutorial I followed exactly. The problem seems to be in the proxy_pass directive. When I move it to the / location block, it works and my index page is overridden with "Hello there!". When I move proxy_params and proxy_pass to a /myproject/ location block, I get a 404 error. I've tried a handful of things and tried to understand location blocks better, but to no avail.

Here is the Nginx config file:

# Default server configuration
#
server {

    root /var/www/html;

    # Add index.php to the list if you are using PHP
    index index.html index.htm index.php;

    server_name example.com www.example.com;

    location / {
        # First attempt to serve request as file, then
        # as directory, then fall back to displaying a 404.
        try_files $uri $uri/ =404;
    }

    location /myproject/ {
        include proxy_params;
        proxy_pass http://unix:/home/jackson/myproject/myproject.sock;
    }

    # pass the PHP scripts to FastCGI server
    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/run/php/php7.0-fpm.sock;
    }

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    location ~ /\.ht {
        deny all;
    }

    listen [::]:443 ssl ipv6only=on; # managed by Certbot
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

}

Any help would be greatly appreciated. Thank you!

Jackson Walters Jackson Walters · Accepted Answer · 2020-03-25T19:53:47

I needed to change the @app.route decorator in the .py file to the correct directly, and I think crucially specify the GET and POST methods.

from flask import Flask
app = Flask(__name__)

@app.route("/myproject/", methods=['GET','POST'])
def hello():
    return "<h1 style='color:blue'>Hello There!</h1>"

if __name__ == "__main__":
    app.run(host='0.0.0.0')

Flask + Gunicorn + Nginx, 404 error using proxy_pass from non-root location block

1 Answers