docker-compose does not start postgres

Question

I m creating a docker-compose config for an django app, the Dockerfile builds successfully but when I compose them up, django return an issue -- cannot connect to postgres.

I run docker-compose run web bash, found redis and posgres both cannot be connected.

My docker-compose.yml file

web:
 build: .
  ports:
    - "8000:8000"
environment:
  - 'DATABASE_HOST=db'
  - 'DATABASE_NAME=mydb'
  - 'DATABASE_USER=root'
  - 'DATABASE_PASSWORD=root'
links:
  - db
db:
  image: postgres:9.1

when running sudo docker-compose up i got the following error.

web_1 |   File "/usr/local/lib/python2.7/site packages/django/db/backends/postgresql/base.py", line 175, in  get_new_connection

web_1 |     connection = Database.connect(**conn_params)
web_1 |   File "/usr/local/lib/python2.7/site-packages/psycopg2/__init__.py", line 164, in connect
web_1 |     conn = _connect(dsn, connection_factory=connection_factory, async=async)
web_1 | django.db.utils.OperationalError: could not connect to server: Connection refused
web_1 |     Is the server running on host "localhost" (::1) and accepting
web_1 |     TCP/IP connections on port 5432?
web_1 | could not connect to server: Connection refused
web_1 |     Is the server running on host "localhost" (127.0.0.1) and accepting
web_1 |     TCP/IP connections on port 5432?

Answer 1

I also built a clustering with docker-compose, it probably will help you and answer your problem (here is the repo). You can see the docker-compose.yml file, and the django settings file (I marked the lines you need).

You can also clone this repo and get django, angular2, postgresql, and nginx containers, all link together already.