nginx gives 502 error with uwsgi for running django on ubuntu 18.04 LTS

Question

Note: I am new to django and its deployment.

Deployed django through uwsgi and nginx according to the steps mentioned in this guide - except the emperor-vassal configuration and without any virtual environment.

Side note: The site comes up using python3 manage.py 0.0.0.0:8800

But, it seems that nginx is facing permission issues in the socket and giving a 502 bad gateway error in the browser.

The nginx error log shows the following error:

2020/07/08 21:05:40 [crit] 3943#3943: *3 connect() to unix:///home/ubuntu/deploymenttst/MySite/MySite.sock failed (13: Permission denied) while connecting to upstream, client: 192.168.12.12, server: 192.168.12.12, request: "GET / HTTP/1.1", upstream: "uwsgi://unix:///home/ubuntu/deploymenttst/MySite/MySite.sock:", host: "192.168.12.12:8400"

The configuration are as follows:

In settings.py file of the project, the configuration are set as (apart from the default wsgi):

DEBUG = False
ALLOWED_HOSTS = [ "192.168.12.12" ]
STATIC_URL = '/static/'
STATICFILES_DIRS = (
    os.path.join(BASE_DIR, 'static'),
)
STATIC_ROOT = os.path.join(BASE_DIR, 'staticfiles')

The MySite_nginx.conf file inside /etc/nginx/sites-available/MySite_nginx.conf has the following configuration entries:

# MySite_nginx.conf

# the upstream component nginx needs to connect to
upstream django {
    server unix:///home/ubuntu/deploymenttst/MySite/MySite.sock; # for a file socket
    #server 127.0.0.1:8008;
}

# configuration of the server
server {
    # the port your site will be served on
    listen      8400;
    # the domain name it will serve for
    server_name 192.168.12.12; # substitute your machine's IP address or FQDN
    charset     utf-8;

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

#    # Django media
    location /media  {
        alias /home/ubuntu/deploymenttst/MySite/media;  # your Django project's media files - amend as required
    }

    location /static {
        #alias /home/ubuntu/deploymenttst/MySite/main/static; # your Django project's static files - amend as required
        #alias /home/ubuntu/deploymenttst/MySite/register/static; # your Django project's static files - amend as required
        alias /home/ubuntu/deploymenttst/MySite/static; # your Django project's static files - amend as required
    }

    # Finally, send all non-media requests to the Django server.
    location / {
        uwsgi_pass  django;
        include     /home/ubuntu/deploymenttst/MySite/uwsgi_params; # the uwsgi_params file you installed
    }
}

It has been sym linked to /etc/nginx/sites-enabled/MySite_nginx.conf.

The uwsgi_params file is made inside the project directory containing the following entries:

uwsgi_param  QUERY_STRING       $query_string;
uwsgi_param  REQUEST_METHOD     $request_method;
uwsgi_param  CONTENT_TYPE       $content_type;
uwsgi_param  CONTENT_LENGTH     $content_length;

uwsgi_param  REQUEST_URI        $request_uri;
uwsgi_param  PATH_INFO          $document_uri;
uwsgi_param  DOCUMENT_ROOT      $document_root;
uwsgi_param  SERVER_PROTOCOL    $server_protocol;
uwsgi_param  REQUEST_SCHEME     $scheme;
uwsgi_param  HTTPS              $https if_not_empty;

uwsgi_param  REMOTE_ADDR        $remote_addr;
uwsgi_param  REMOTE_PORT        $remote_port;
uwsgi_param  SERVER_PORT        $server_port;
uwsgi_param  SERVER_NAME        $server_name;

The content inside the MySite_uwsgi.ini file is as follows:

[uwsgi]

# Django-related settings
# the base directory (full path)
chdir           = /home/ubuntu/deploymenttst/MySite
# Django's wsgi file
module          = MySite.wsgi
# the virtualenv (full path)
#home            = /home/ubuntu/deploymenttst/MySite/

# process-related settings
# master
master          = true
# maximum number of worker processes
processes       = 20
# the socket (use the full path to be safe
socket          = /home/ubuntu/deploymenttst/MySite/MySite.sock
# ... with appropriate permissions - may be needed
chmod-socket    = 666
uid = www-data
gid = www-data
# clear environment on exit
vacuum          = true

Static files have been collected inside a static directory inside the project directory using python3 manage.py collectstatic
In one of the terminal windows, the uwsgi process is started successfully using: uwsgi --ini MySite_uwsgi.ini
nginx has been stopped and started and restarted multiple time upon each configuration change and otherwise as well.
The uid:gid of the MySite project directory has been set to www-data:www:data using sudo chown -R www-data:www:data *

Why am I still getting that bad gateway 502 error wherein upstream django application cannot be contacted due to permission issues?

Thanks for the edit @james-z Solved the issue by placing the project inside the /tmp directory. — Usertester52

Usertester52 Usertester52 · Accepted Answer · 2020-07-09T10:20:25

Solved the issue by placing the project to /tmp directory.

nginx being run from www-data user was not able to access the internal directory MySite and thus the socket or the files placed there, despite being assigned to the user www-data.

Now, my other question is regarding the cause of permission issue for nginx, despite providing the the uid and gid of the directory to www-data, what could have been the issue?

Note: My user named ubuntu is a sudoer.

nginx gives 502 error with uwsgi for running django on ubuntu 18.04 LTS

1 Answers