Sending a curl request to a dockerized nginx+gunicorn+flask app #2639

IavTavares · 2022-05-02T13:46:45Z

IavTavares
May 2, 2022

In the dockerfile of my app, I've exposed port 5000, using: EXPOSE 5000.
The container has the same structure as the original root project directory, which is ensured by COPY . ., in the dockerfile .
In the gunicorn.conf.py file, I have the following:

worker_class = "gevent"
workers = 2
timeout = 90
bind = "0.0.0.0:5000"
wsgi_app = "wsgi:app"
errorlog = "logging/error.log"
capture_output = True
loglevel = "debug"
daemon = True
enable_stdio_inheritance = True
preload = True

To run the image: $ docker run -it -p 8000:5000 <image_name> bash
Inside the container, I run: $ gunicorn --bind 0.0.0.0:5000 && /usr/sbin/nginx
If I look at the processes inside the container:

PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND                                                      
      1 root      20   0    4624   3808   3216 S   0.0   0.0   0:00.03 bash                                                         
     14 root      20   0   12868    880     12 S   0.0   0.0   0:00.00 nginx                                                        
     15 nginx     20   0   13288   2540   1376 S   0.0   0.0   0:00.00 nginx                                                        
     16 nginx     20   0   13288   2540   1376 S   0.0   0.0   0:00.00 nginx                                                        
    155 root      20   0    7356   3444   2892 R   0.0   0.0   0:00.00 top

Outside the container, if I wanted to do the curl request, I would use something like:
curl --request POST --url https://<dns>/<flask_route> --header 'Content-Type: application/json' --data '{"field": "value"}'

where and <flask_route> should be substituted for the real values.

In the nginx.conf file:

upstream <dns> {
        server 0.0.0.0:5000;
}

server {

        listen 443;
        error_log  /var/log/nginx/error.log;
        access_log /var/log/nginx/access.log;

        location / {
            proxy_pass https://<dns>;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Host $host;
            proxy_redirect off;
            proxy_set_header   X-Real-IP            $remote_addr;
            proxy_set_header   X-Forwarded-Proto    $scheme;
        }

        location /nginx_status {
            stub_status;
        }
        
}

Now, when I do, outside the container, in a client:
curl https://<dns>/nginx_status

I receive the following content:

<html>
<head><title>502 Bad Gateway</title></head>
<body>
<center><h1>502 Bad Gateway</h1></center>
<hr><center>nginx/1.18.0 (Ubuntu)</center>
</body>
</html>

Answered by IavTavares

May 4, 2022

The problem was when binding gunicorn, I should have done:
$ docker run -it -p 5000:5000 <image_name> bash

Both 5000...

View full answer

IavTavares · 2022-05-04T19:38:57Z

IavTavares
May 4, 2022
Author

The problem was when binding gunicorn, I should have done:
$ docker run -it -p 5000:5000 <image_name> bash

Both 5000...

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Sending a curl request to a dockerized nginx+gunicorn+flask app #2639

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Sending a curl request to a dockerized nginx+gunicorn+flask app #2639

IavTavares May 2, 2022

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IavTavares May 4, 2022 Author

IavTavares
May 2, 2022

IavTavares
May 4, 2022
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