docker-compose: using multiple Dockerfiles for multiple services
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
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
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).
2 Solutions collect form web for “docker-compose: using multiple Dockerfiles for multiple services”
This is not possible due to the way Docker handles build contexts.
You will have to use and place a
Dockerfile in each directory that becomes part of the Docker build context for that service.
You will in fact require a
docker-compose.yml that looks like:
service1: build: service1 service2: build: service2
To address your particular use-case — Whilst I understand what you’re trying to do and why I personally wouldn’t do this myself. The isolation is a good thing and helps to manage expectations and complexity. I would perform the “database creation” as either another container based off your app’s source code or within the app container itself.
Alternatively you could look at more scripted and template driven solutions such as shutit (I have no experience in but heard god thigns about).
FWIW: Separation of concerns ftw 🙂
Creator of ShutIt here. Gratified to hear that people are hearing good things about it.
To be honest, in your position I’d write your own Dockerfile and use standard package management such as apt or yum. A quick check with an ubuntu image and python-pip and python-sqlalchemy are freely available.
There are more convoluted solutions that may work for you using ShutIt, happy to discuss this offline, as I think it’s a bit off-topic. ShutIt was written for this kind of use case, as I could see that this would be a common problem given Dockerfiles’ limited utility outside the microservices space.