Chapter 11. 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 do not 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

   Example output

   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:

   $ git init

   $ git add .

   $ git commit -m "initial commit"

   After your application is committed you must push it to a remote repository. GitHub account, in which you create a new repository.

3. Set the remote that points to your

   git

   repository:

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

4. 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

   deployment config:

   $ oc get dc rails-app -o json

   You should see the following section:

   Example output

   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. After 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 is 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 do not have to specify the

       RAILS_ENV

       environment variable.

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