Docker compose profiles

It’s been a while since my previous blog post, long enough for dockercon 2021 to suprise us with some exciting features. My review of some of the features is on the way but for this post I would like to discuss one of my most anticipated compose features, profiles.

If you remember my previous docker blog post, in order to modularize container services, I decided to use docker-compose.yml overriding to start different services for different environments. You can finally add services to one or multiple profiles and then start one or multiple profiles.

Demo

Let’s say we have three environments:

1. dev: Hotreloading with typescript without building.
2. test: Running integration tests.
3. prod: Running in the production environment in a lightweight container.

The setup used here is the same as in the previous post, where we have a node app, postgres as database with docker volumes and a multistage Dockerfile. We can now setup our new single docker-compose.yml with 3 profiles: api-dev, api-test, api-prod as follows:

version: "3.9"
services:
    db:
        image: postgres:13-alpine
        environment:
            - POSTGRES_PASSWORD=${POSTGRES_PASSWORD}
            - POSTGRES_USER=${POSTGRES_USER}
            - POSTGRES_DB=${POSTGRES_DB}
        container_name: db-dev
        ports: 
            - '5432:5432'
        volumes:
            - dbdata:/var/lib/postgresql/data/
            - ./dbscripts:/docker-entrypoint-initdb.d

    api-dev:
        image: yzia2000/temp-api:dev
        environment:
            - DATABASE_URL=postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@db:5432/${POSTGRES_DB}
        build:
            context: .
            target: base
        container_name: api-dev
        command: npm run dev
        volumes:
            - ./src:/app/src
            - ./package.json:/app/package.json
        depends_on:
            - db
        ports:
            - '5000:5000'
        profiles: ['api-dev']

    api-test:
        image: yzia2000/temp-api:test
        environment:
            - DATABASE_URL=postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@db:5432/${POSTGRES_DB}
            - NODE_ENV=test
        build:
            context: .
            target: builder
        container_name: api-test
        command: ./wait-for-it.sh db:5432 -- /bin/sh -c "npm run test"
        depends_on:
            - db
        ports:
            - '5000:5000'
        profiles: ['api-test']

    api-prod:
        image: yzia2000/temp-api:latest
        environment:
            - DATABASE_URL=postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@db:5432/${POSTGRES_DB}
            - NODE_ENV=production
        build:
            context: .
        container_name: api
        depends_on:
            - db
        ports:
            - '5000:5000'
        profiles: ['api-prod']

volumes:
    dbdata:

To run a profile, simply:

docker-compose --profile api-dev up

If you have some knowledge of docker-compose.yml, this will look self-explanatory. Profiles are easy to understand too. You might find the lack of a profile attached to the db container interesting. Containers that do not have a profile attached to them start automatically. Since, all our profiles depend on the db container, we do not need to attach multiple profiles to it.

Profiles can be especially useful when onboarding new members into your team as they no longer need to worry about starting or stopping different containers and can get to work immediately. This is one of the ways you can reduce developer cold start (new post coming soon).

To learn more about docker compose profiles you can read the docker documentation.

Conclusion

Now you longer need to maintain multiple docker-compose.yml, though I would recommend doing that if you different teams on a monorepo setup (separated by feature and not environment). Having a single docker-compose.yml means that you spend less time moving through different files when changing things as simple as environment variables.

More docker features from the dockercon 2021 will be discussed soon in my upcoming blog posts and I hope you look forward to them.