Using Docker-Compose, how to execute multiple comm

Question

I want to do something like this where I can run multiple commands in order.

db:
  image: postgres
web:
  build: .
  command: python manage.py migrate
  command: python manage.py runserver 0.0.0.0:8000
  volumes:
    - .:/code
  ports:
    - "8000:8000"
  links:
    - db

Answer 1

I run pre-startup stuff like migrations in a separate ephemeral container, like so (note, compose file has to be of version '2' type):

db:
  image: postgres
web:
  image: app
  command: python manage.py runserver 0.0.0.0:8000
  volumes:
    - .:/code
  ports:
    - "8000:8000"
  links:
    - db
  depends_on:
    - migration
migration:
  build: .
  image: app
  command: python manage.py migrate
  volumes:
    - .:/code
  links:
    - db
  depends_on:
    - db

This helps things keeping clean and separate. Two things to consider:

1. You have to ensure the correct startup sequence (using depends_on)

2. you want to avoid multiple builds which is achieved by tagging it the first time round using build and image; you can refer to image in other containers then

Answer 2

Figured it out, use bash -c.

Example:

command: bash -c "python manage.py migrate && python manage.py runserver 0.0.0.0:8000"

Same example in multilines:

command: >
    bash -c "python manage.py migrate
    && python manage.py runserver 0.0.0.0:8000"

Answer 3

Another idea:

If, as in this case, you build the container just place a startup script in it and run this with command. Or mount the startup script as volume.

Answer 4

I recommend using sh as opposed to bash because it is more readily available on most unix based images (alpine, etc).

Here is an example docker-compose.yml:

version: '3'

services:
  app:
    build:
      context: .
    command: >
      sh -c "python manage.py wait_for_db &&
             python manage.py migrate &&
             python manage.py runserver 0.0.0.0:8000"

This will call the following commands in order:

• python manage.py wait_for_db - wait for the db to be ready
• python manage.py migrate - run any migrations
• python manage.py runserver 0.0.0.0:8000 - start my development server