docker-compose: using multiple Dockerfiles for multiple services

Question

I'm using docker-compose and I'd like to use different Dockerfiles for different services' build steps. The docs seem to suggest to place different Dockerfiles in different directories, but I'd like them all to be in the same one (and perhaps distinguishable using the following convention: Dockerfile.postgres, Dockerfile.main...). Is this possible?

Edit: The scenario I have contains this docker-compose file:

main:
  build: .
  volumes:
    - .:/code
  environment:
    - DEBUG=true

postgresdb:
  extends:
    file: docker-compose.yml
    service: main
  build: utils/sql/
  ports:
    - "5432"
  environment:
    - DEBUG=true

where postgresdb's Dockerfile is:

FROM postgres

# http://www.slideshare.net/tarkasteve/developerweek-2015-docker-tutorial
ADD make-db.sh /docker-entrypoint-initdb.d/

and the main is:

FROM python:2.7

RUN mkdir /code
WORKDIR /code
ADD requirements.txt /code/

RUN pip install --upgrade pip
RUN pip install -r requirements.txt
ADD . /code/

This works right now, but I'd like to extend postgresdb's Dockerfile by calling a Python script that creates tables in the database according to models built upon SQL Alchemy (the Python script would be called as python manage.py create_tables). I wanted to add it to the db's Dockerfile, but due to the isolation of the containers I can't use SQL Alchemy there because that image is based on the postgres image instead of Python's, and it doesn't contain the sqlalchemy package...

What can I do? I tried to use the main service in postgresdb, but unfortunately it doesn't carry python and its packages over, so I still can't write a single Dockerfile that creates the Postgres database (through the shell script) as well as its tables (through a Python script).

Answer 1

You have to add it in build section. So, you can specify different alternative dockerfiles for each service.

services:
  service1:
    build:
        context: .
        args:
            - NODE_ENV=local
        dockerfile: Dockerfile_X
    ports:
        - "8765:8765"