Docker Compose for Rails - ruby-on-rails

Question

I'm trying to replicate this docker command in a docker-compose.yml file
docker run --name rails -d -p 80:3000 -v "$PWD"/app:/www -w /www -ti rails
My docker-compose.yml file:
rails:
image: rails
container_name: rails
ports:
- 80:3000
volumes:
- ./app:/wwww
When I'm doing docker-compose up -d, the container is created but it does not strat.
When I'm adding tty: true to my docker docker-compose.yml file, the container start well but my volume is not mounted.
How can I replicate excatly my docker command in a docker-compose.yml?

Answer 1

There are some ways to solve your problem.
Solution 1: If you want to use the rails image in your docker-compose.yml, you need to set the command and working directory for it like
rails:
image: rails
container_name: rails
command: bash -c "bundle install && rails server -b 0.0.0.0"
ports:
- 80:3000
volumes:
- ./app:/www
working_dir: /www
This will create a new container from the rails image every time you run docker-compose up.
Solution 2: Move your docker-compose.yml to the same directory with Gemfile, and create Dockerfile in that directory in order to build a docker container in advance (to avoid running bundle installevery time)
#Dockerfile
FROM rails:onbuild
I use rails:onbuild here for simplicity reasons (about the differences between rails:onbuild and rails:<version>, please see the documentation).
After that, modify the docker-compose.yml to
rails:
build: .
container_name: rails
ports:
- 80:3000
volumes:
- .:/www
working_dir: /www
Run docker-compose up and this should work!
If you modify your Gemfile, you may also need to rebuild your container by docker-compose build before running docker-compose up.

Answer 2

Thanks for your answer. It helped me to find the solutions.
It was actually a volume problem. I wanted to mount the volume with the directory /www. But it was not possible.
So I used the directory used by default with the rails images:
/usr/src/app
rails:
image: rails
container_name: rails
ports:
- 80:3000
working_dir: /usr/src/app
volumes:
- ./app:/usr/src/app
tty: true
Now my docker-compose up -d command works