Push Rails 6 application to Docker Hub - ruby-on-rails

Question

I'm trying to get my head around docker. I got it working with my Rails 6 application, it builds and runs succesful. Now I want to push the application into my docker hub repository.
I'm not quite sure how to do this, because I got 3 containers but in every tutorial I read the people just push one.
That's the output of docker ps -a:
That's my docker-compose.yml:
version: '3'
services:
db:
image: postgres
volumes:
- postgres:/var/lib/postgresql/data
env_file:
- .env
ports:
- "5432"
web:
build: .
command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
volumes:
- .:/webmenue
- bundler_gems:/bundle
- ./docker/database.yml:/webmenue/config/database.yml
- cache:/cache
ports:
- "3000:3000"
env_file:
- .env
environment:
- RAILS_ENV=development
- WEBPACKER_DEV_SERVER_HOST=webpacker
- SPROCKETS_CACHE=/cache
depends_on:
- db
webpacker:
build: .
command: ./bin/webpack-dev-server
volumes:
- .:/webmenue
ports:
- '3035:3035'
environment:
- NODE_ENV=development
- RAILS_ENV=development
- WEBPACKER_DEV_SERVER_HOST=0.0.0.0
volumes:
postgres:
bundler_gems:
cache:
I read about the --link flag, but this seems to be deprecated.
So: Do I need to push all containers or is there a way to get them into one container?

Answer 1

That is easy in short as simple as: if you have multiple images, you need to push multiple times ;)
Now the helpful answer, you have 2 images: postgress and your current working directory. Postgress is already an image you download from docker hub, so no need to push it.
As for your other 2 apps, they are currently in one docker file, so only one push is needed.
In your compose file they are both using the build: ., therefore they share the docker image. Let's say you pushed it with: docker push max-kirsch/my-cool-app:1.0.0, you would change the docker compose file to look like this:
version: '3'
services:
db:
image: postgres
volumes:
- postgres:/var/lib/postgresql/data
env_file:
- .env
ports:
- "5432"
web:
image: max-kirsch/my-cool-app:1.0.0
command: bash -c "rm -f tmp/pids/server.pid && bundle exec rails s -p 3000 -b '0.0.0.0'"
volumes:
- .:/webmenue
- bundler_gems:/bundle
- ./docker/database.yml:/webmenue/config/database.yml
- cache:/cache
ports:
- "3000:3000"
env_file:
- .env
environment:
- RAILS_ENV=development
- WEBPACKER_DEV_SERVER_HOST=webpacker
- SPROCKETS_CACHE=/cache
depends_on:
- db
webpacker:
image: max-kirsch/my-cool-app:1.0.0
command: ./bin/webpack-dev-server
volumes:
- .:/webmenue
ports:
- '3035:3035'
environment:
- NODE_ENV=development
- RAILS_ENV=development
- WEBPACKER_DEV_SERVER_HOST=0.0.0.0
volumes:
postgres:
bundler_gems:
cache:
I think you are confused because you have 2 apps in your compose file that shares the same docker file. And it might be that this confusing is correct. In my personal opinion, you should create them both there ow docker file where only the components are installed that you need. It is hard to be sure without seeing the docker file, but as an example, it does not look like your webpacker needs ruby installed and can start with a simple node image as the base instead of installing node in your ruby image.