Using Docker-Compose, how to execute multiple commands

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

Solution 1:

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"

Or:

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

Solution 2:

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.

Solution 3:

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

Solution 4:

This works for me:

version: '3.1'
services:
  db:
    image: postgres
  web:
    build: .
    command:
      - /bin/bash
      - -c
      - |
        python manage.py migrate
        python manage.py runserver 0.0.0.0:8000

    volumes:
      - .:/code
    ports:
      - "8000:8000"
    links:
      - db

docker-compose tries to dereference variables before running the command, so if you want bash to handle variables you'll need to escape the dollar-signs by doubling them...

    command:
      - /bin/bash
      - -c
      - |
        var=$$(echo 'foo')
        echo $$var # prints foo

...otherwise you'll get an error:

Invalid interpolation format for "command" option in service "web":

Solution 5:

Cleanest ?

---
version: "2"
services:
  test:
    image: alpine
    entrypoint: ["/bin/sh","-c"]
    command:
    - |
       echo a
       echo b
       echo c