How to execute psql interactive in its docker container?

Question

I want to run a query in Postgres interactive shell. I'm using a docker container for this purpose as follows:

Here is the relevant piece of docker-compose:

  db_of_ivms:
    image: postgres:10
    restart: unless-stopped
    ports:
     - 5432:5432
    container_name: db_of_ivms
    environment:
      POSTGRES_PASSWORD: xxx
      POSTGRES_USER: ivms_usr
      POSTGRES_DB: ivms_db

Nevertheless, I'm dealing with this error:

docker exec -it -u 0 db_of_ivms bash

# psql

psql: FATAL:  role "root" does not exist

Answer 1

You need shell in with the postgres user

docker exec -it -u postgres db_of_ivms bash

Now for containers that you dont specify POSTGRES_USER: ivms_usr:

postgres@d9b097b8db8c:/$ psql
postgres=# \l
                                 List of databases
   Name    |  Owner   | Encoding |  Collate   |   Ctype    |   Access privileges   
-----------+----------+----------+------------+------------+-----------------------
 postgres  | postgres | UTF8     | en_US.utf8 | en_US.utf8 | 
 template0 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
           |          |          |            |            | postgres=CTc/postgres
 template1 | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =c/postgres          +
           |          |          |            |            | postgres=CTc/postgres
(3 rows)

If you specify POSTGRES_USER: ivms_usr and Database (note psql command arguments):

docker exec -it -u postgres db_of_ivms bash
postgres@2cec2435bb83:/$ psql -U ivms_usr -d ivms_db
psql (10.12 (Debian 10.12-1.pgdg90+1))
Type "help" for help.

ivms_db=# \l
                                 List of databases
   Name    |  Owner   | Encoding |  Collate   |   Ctype    |   Access privileges   
-----------+----------+----------+------------+------------+-----------------------
 ivms_db   | ivms_usr | UTF8     | en_US.utf8 | en_US.utf8 | 
 postgres  | ivms_usr | UTF8     | en_US.utf8 | en_US.utf8 | 
 template0 | ivms_usr | UTF8     | en_US.utf8 | en_US.utf8 | =c/ivms_usr          +
           |          |          |            |            | ivms_usr=CTc/ivms_usr
 template1 | ivms_usr | UTF8     | en_US.utf8 | en_US.utf8 | =c/ivms_usr          +
           |          |          |            |            | ivms_usr=CTc/ivms_usr
(4 rows)

Answer 2

I use this procedure for example for getting dump:

docker exec -it -u 0 <container-name> bash

Now, you could enter psql commands with root permission:

# pg_dump -U <user-name> <db-name> > dump.sql

Answer 3

I've found an alternative approach through Django shell:

$ python manage.py shell

from django.db import connection

cursor = connection.cursor()
cursor.execute("DELETE FROM django_migrations WHERE app='settings'")