Chapter 8. Using Ruby on Rails

Procedure

1. Run Rails generator:

   $ rails generate controller welcome index

   All the necessary files are created.

2. edit line 2 in config/routes.rb file as follows:

   root 'welcome#index'

3. Run the rails server to verify the page is available:

   $ rails server

   You should see your page by visiting http://localhost:3000 in your browser. If you don’t see the page, check the logs that are output to your server to debug.

Procedure

1. Make sure you are in your Rails application directory by running the ls -1 command. The output of the command should look like:

   $ ls -1
   app
   bin
   config
   config.ru
   db
   Gemfile
   Gemfile.lock
   lib
   log
   public
   Rakefile
   README.rdoc
   test
   tmp
   vendor

2. Run the following commands in your Rails app directory to initialize and commit your code to git:

1. Set the remote that points to your git repository:

   $ git remote add origin git@github.com:<namespace/repository-name>.git

2. Push your application to your remote git repository.

   $ git push

Procedure

1. Create the database service:

   $ oc new-app postgresql -e POSTGRESQL_DATABASE=db_name -e POSTGRESQL_USER=username -e POSTGRESQL_PASSWORD=password

   To also set the password for the database administrator, append to the previous command with:

   -e POSTGRESQL_ADMIN_PASSWORD=admin_pw

2. Watch the progress:

   $ oc get pods --watch

Procedure

1. Create the frontend service and specify database related environment variables that were setup when creating the database service:

   $ oc new-app path/to/source/code --name=rails-app -e POSTGRESQL_USER=username -e POSTGRESQL_PASSWORD=password -e POSTGRESQL_DATABASE=db_name -e DATABASE_SERVICE_NAME=postgresql

   With this command, OpenShift Container Platform fetches the source code, sets up the builder builds your application image, and deploys the newly created image together with the specified environment variables. The application is named rails-app.

2. Verify the environment variables have been added by viewing the JSON document of the rails-app DeploymentConfig:

   $ oc get dc rails-app -o json

   You should see the following section:

   env": [
       {
           "name": "POSTGRESQL_USER",
           "value": "username"
       },
       {
           "name": "POSTGRESQL_PASSWORD",
           "value": "password"
       },
       {
           "name": "POSTGRESQL_DATABASE",
           "value": "db_name"
       },
       {
           "name": "DATABASE_SERVICE_NAME",
           "value": "postgresql"
       }
   
   ],

3. Check the build process:

   $ oc logs -f build/rails-app-1

4. Once the build is complete, look at the running pods in OpenShift Container Platform:

   $ oc get pods

   You should see a line starting with myapp-<number>-<hash>, and that is your application running in OpenShift Container Platform.

5. Before your application will be functional, you must initialize the database by running the database migration script. There are two ways you can do this:

   • Manually from the running frontend container:

     • Exec into frontend container with rsh command:

         $ oc rsh <FRONTEND_POD_ID>

     • Run the migration from inside the container:

         $ RAILS_ENV=production bundle exec rake db:migrate

       If you are running your Rails application in a development or test environment you don’t have to specify the RAILS_ENV environment variable.

   • By adding pre-deployment lifecycle hooks in your template.