django.db.utils.OperationalError：无法连接到服务器：Unix 域套接字“/tmp/.s.PGSQL.5432”上没有此类文件？

Question

When I connect Postgres database with Django , it gives me following error (screenshot attached either). When I use direct database name or user etc then this work fine but when i use through environment variable, it is not working.

this is my setting.py file:

'ENGINE': 'django.db.backends.postgresql_psycopg2',

        'NAME': os.environ.get('DATABASE_NAME'),
        'USER': os.environ.get('DATABASE_USER'),
        'PASSWORD': os.environ.get('DATABASE_PASSWORD'),
        'HOST': os.environ.get('DATABASE_HOST'),
        'PORT': 5432
    this is my .bash_profile enviroment variable
    
     export DATABASE_NAME='blog'
     export DATABASE_USER='bloguser'
     export DATABASE_PASSWORD='blog@123'
     export DATABASE_HOST='localhost'

The error itself:

    self.connection = self.get_new_connection(conn_params)
  File "/home/kamran/anaconda3/envs/DjangoEnv/lib/python3.8/site-packages/django/db/backends/postgresql/base.py", line 178, in get_new_connection
    connection = Database.connect(**conn_params)
  File "/home/kamran/anaconda3/envs/DjangoEnv/lib/python3.8/site-packages/psycopg2/__init__.py", line 127, in connect
    conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
django.db.utils.OperationalError: could not connect to server: No such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket "/tmp/.s.PGSQL.5432"?

And the attached image: https://i.stack.imgur.com/fqrZQ.png

Answer 1

PostgreSQL is not running or it's not configured properly.

Change listen_address localhost to * in file /etc/postgresql/{version_number}/main/postgresql.conf

listen_addresses = '*'

In pg_hba.conf , add the following line in # IPv4 local connections :

host    all             all             0.0.0.0/0               md5

Answer 2

Sure, you can go to the code and place the pdb before the self.connection = self.get_new_connection(conn_params) line, something like:

import pdb; pdb.set_trace()
self.connection = self.get_new_connection(conn_params)

Run the server and once it reaches that pdb line you could interact with the code in runtime mode, it will show you a pdb console and then you can see if that environment variables are setted or not:

(pdb) p os.environ.get('DATABASE_NAME')
(pdb) p os.environ.get('DATABASE_USER')
...

It will allow you to see if the variables are setted and with the correct value.