Docker-compose.yml file that builds a base image, then children based on it?

Will Parzybok picture Will Parzybok · Jul 18, 2017 · Viewed 13.1k times · Source

For clarification, when I say base image, I mean the parent image that has all the common configurations, so that the children based on it don't need to download the dependencies individually.

From my understanding, docker-compose.yml files are the run-time configurations, while Dockerfiles are the build-time configurations. However, there is a build option using docker-compose, and I was wondering how I could use this to build a base image.

As of right now, I use a shellscript that runs other shellscripts. One builds all my images, from a base image that it also creates. The other runs them as containers with the necessary configurations. However, the base image is never ran as a container.

Currently, the shellscript I hope to change into a docker-compose file, looks like so:

echo "Creating docker network net1"
docker network create net1

echo "Running api as a container with port 5000 exposed on net1"
docker run --name api_cntr --net net1 -d -p 5000:5000 api_img

echo "Running redis service with port 6379 exposed on net1"
docker run --name message_service --net net1 -p 6379:6379 -d redis

echo "Running celery worker on net1"
docker run --name celery_worker1 --net net1 -d celery_worker_img

echo "Running flower HUD on net1 with port 5555 exposed"
docker run --name flower_hud --net net1 -d -p 5555:5555 flower_hud_img

The shellscript that makes the images, is as follows:

echo "Building Base Image"
docker build -t base ../base-image

echo "Building api image from Dockerfile"
docker build -t api_img  ../api

echo "Building celery worker image"
docker build -t celery_worker_img ../celery-worker

echo "Building celery worker HUD"
docker build -t flower_hud_img ../flower-hud

My questions comes down to one thing, can I create this Base image without ever running it in a container with docker-compose. (All the Dockerfiles start with FROM base:latest other than the base itself). I'm looking to make it as easy as possible for other people, so that they only have to run a single command.

EDIT: I am using version 3, and acording to the docs, build: is ignored, and docker-compose only accepts pre-built images.

Answer

Kanedias picture Kanedias · Jul 4, 2018

Yes, kind of. Use it like this:

version: '2'

services:

    wls-admin:
        container_name: wls-admin
        image: weblogic-domain
        build:
            context: wls-admin
            args:
                - ADMIN_PORT=${WLS_ADMIN_PORT}
                - CLUSTER_NAME=${WLS_CLUSTER_NAME}
                - PRODUCTION_MODE=dev
        networks:
            - wls-network

image clause here makes docker-compose build generate docker image named weblogic-domain for this service. This image can be re-used by other services' Dockerfiles, even in the same build process.