In the previous exercise you created a docker container. In this exercise you will use docker compose to create multiple docker containers and linking them all together to create an development environment for a Ruby on Rails application.
We have created the base RoR application and a empty Dockerfile to get you started. If you want to use this pre-created repo you will have tor use this command:
#First navigate to your exercise repository
git remote add docker-compose-ror-dev https://github.com/1dv032/exercise-docker-compose-ror-dev.git
git subtree add --prefix=docker-compose-ror-dev --squash docker-compose-ror-dev master
You should create a docker-compose.yml file that should define the following containers:
Our app uses a Postgres database, it should use postgres:9.5. Our app needs to able to contact the database so don't forget to expose the port 5432. We want to be able to take backups of the database so you should put the database files in an volume, the files are located here /var/lib/postgresql/data
We use Redis as a cache server and the image redis:latest should work fine. We want the cache data to be in its own volume, the location of the data is /var/lib/redis/data. Lastly, don't forget to expose the port 6379
This container should use the predefined Dockerfile and need links to both the database and the redis containers. We want to be able to continue development once the containers are running. Here we have an predefined environment file we want to use .todo.env.
Once you are done with the compose file you should be able to run docker-compose up
The first time you will probably get en error that the database stoped, we need to create the database.
docker-compose run todo rake db:reset
docker-compose run todo rake db:migrate
docker-compose up
Now that the containers are up you should be able to go to http://localhost:8000
We can now continue development our RoR app:
# We want to be able to create tasks in our Todo app, so lets scaffold that.
# You should have the containers running so open a new terminal and run.
docker-compose run todo rails generate scaffold Task name:string completed:boolean created:datetime
# We want the change to be reflected in the database so we need to do a migrate.
docker-compose run todo rake db:migrate
Now you cant create tasks http://localhost:8000/tasks
If you want to get the tasks page as the main page for the app you need to edit the Routes File config/routes.rb.
After the resources :tasks line near the top add the following line:
root 'tasks#index'