CODEWITHSUNDEEP
ruby-on-railsdockerdocker-composemicroservices
Fran Martinez
Fran Martinez

Reputation: 3052

Docker, independent multiple rails instances

I an trying to create a development environment with multiple microservices running like in a production environment.

I would like to run with Docker two rails applications that makes calls between them.

I know that I can use links, but with this I always has to run one of them as the master one. That means, that I only can debug this one, and I would like to see the console ouput of each of them. Maybe I am doing something wrong, and that's why I am asking.

This is my docker-compose.yml file:

rails-app-A:
  build: .
  dockerfile: "DockerfileA"
  environment:
    RAILS_ENV: development
  links:
    - db
  command: bundle exec rails server -p 3005 -b '0.0.0.0'
  volumes:
    - ".:/home/app"
  volumes_from:
    - bundle
  expose:
    - "3005"
  ports:
    - "3005:3005"

rails-app-B:
  build: .
  dockerfile: "DockerfileB"
  environment:
    RAILS_ENV: development
  links:
    - db
  command: bundle exec rails server -p 3000 -b '0.0.0.0'
  volumes:
    - ".:/home/app"
  volumes_from:
    - bundle
  expose:
    - "3000"
  ports:
    - "3000:3000"

This is how I run the rails app:

docker-compose run --service-ports rails-app-A
docker-compose run --service-ports rails-app-B

I always get errors like these:

Errno::ECONNREFUSED: Connection refused - connect(2) for "localhost" port 3000

Errno::ECONNREFUSED (Failed to open TCP connection to localhost:3000 (Connection refused - connect(2) for "localhost" port 3000))

The thing is that I can access to all of them with the browser.

With the Docker version for OSX using VirtualBox this was working fine (just calling localhost:3000 or localhost:3005), but in Ubuntu or with Docker-beta, is failing.

EDIT

I understand that "localhost" for rails-app-A is a different server as "localhost" in rails-app-B, because they run as different machines. When I had VirtualBox I could access because I had the IP of the VirtualBox instance (192.169.99.100).

I am now using http://localtunnel.me/ and I can access to the other services. But, anyway, Is there a better way to do this?

Upvotes: 3

Views: 1341

Answers (1)

Fran Martinez
Fran Martinez

Reputation: 3052

Finally, I achieve to call external services using an external_link:

rails-app-A:
  build: .
  dockerfile: "DockerfileA"
  environment:
    RAILS_ENV: development
  links:
    - db
  external_links:
    - app_B

  ...ommited lines...

app_B should be a running container, previously executed like this:

docker-compose run --service-ports --name app_B rails-app-B

Adding this --name app_B makes it accessible using this name.

What I still don't understand is how to build rails-app-A without previously open rails-app-B. If rails-app-A has rails-app-B as external link and the same happens in the other direction, builds become unmanageable.

Upvotes: 1

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