Deploying a Merb application with the RailsMachine gem

0 comments

I recently launched a monthly bill/task tracking application I've been working on in my spare time. I used Merb so I could get some experience with the framework.

Plexus was kind enough to donate some server space on a RailsMachine server. Luckily, they recently added Passenger support to their awesome RailsMachine gem, so all I needed was to add a Rack config file to run my app on Passenger.

require 'rubygems'
require 'merb-core'
 
Merb::Config.setup(:merb_root => File.expand_path(File.dirname(__FILE__)),
                   :environment => ENV['RACK_ENV'])
Merb.environment = Merb::Config[:environment]
Merb.root = Merb::Config[:merb_root]
Merb::BootLoader.run
 
run Merb::Rack::Application.new

After that, I only needed to update the Capistrano deploy file to work with Merb and Passenger.

require 'railsmachine/recipes'
 
# The name of your application. Used for directory and file names associated with
# the application.
set :application, "listode"
 
# Target directory for the application on the web and app servers.
set :deploy_to, "/var/www/apps/#{application}"
 
# Primary domain name of your application. Used as a default for all server roles.
set :domain, "listode.com"
 
# Login user for ssh.
set :user, "deploy"
set :runner, user
set :admin_runner, user
 
# Rails environment. Used by application setup tasks and migrate tasks.
set :rails_env, "production"
 
# Automatically symlink these directories from curent/public to shared/public.
set :app_symlinks, %w{graphs}
 
set :deploy_via, :remote_cache
 
# =============================================================================
# ROLES
# =============================================================================
# Modify these values to execute tasks on a different server.
role :web, domain
role :app, domain
role :db, domain, :primary => true
role :scm, domain
 
 
# =============================================================================
# APPLICATION SERVER OPTIONS
# =============================================================================
set :app_server, :passenger # :mongrel or :passenger
 
# =============================================================================
# SCM OPTIONS
# =============================================================================
set :scm, :git # :subversion or :git
set :repository, "git@github.com:travisr/#{application}.git"
 
# =============================================================================
# CUSTOM CONFIGURATION
# =============================================================================
# action to symlink database file
namespace :deploy do
  desc "Symlink database config file."
  task :symlink_db do
    run "ln -nfs #{shared_path}/system/database.yml #{release_path}/config/database.yml"
  end
end
 
# Overwrite the default deploy.migrate as it calls:
# rake RAILS_ENV=production db:migrate
desc "Use datamapper to call autoupgrade instead of db:migrate."
deploy.task :migrate do
 run "cd #{release_path}; rake db:autoupgrade MERB_ENV=production"
end

after 'deploy:update_code', 'deploy:symlink_db'

The custom section at the bottom sets up a symlink to my databases.yml file since I don't keep that in my git repo. I also have to override the migration action to use DataMapper's db:autoupgrade.

Tagged: rails machine, capistrano, passenger, merb, tutorial

Create your own custom rails generator

2 comments

It's really easy to add a custom generator to your Rails application. Say you have a component you want to include in multiple projects, but you don't want to manually copy ALL of the files from project to project. At Plexus, we have an empty Rails project with basic styling and structure that we use for all new applications. We have several components that we wanted to simplify adding to new projects. So, we created a few custom generators that we can use to create the components with very little effort.

The first thing you need to do is add a generators folder inside the lib folder. In there you can add the files and folders for each custom generator. In this example, I'll use a Blog as the component I'm building a generator for.

Inside the generators folder, I created a blog folder (hint: whatever you name the folder will be how you call your custom generator). All of my files for the blog functionality will be in this folder. The two most important things in this folder are the actual generator file that will do all of the work and the templates folder which contains all the files to be copied. My blog generator file, blog_generator.rb looks like this:

class BlogGenerator < Rails::Generator::Base
  def manifest
    record do |m|

      # Controllers
      m.file "controllers/blog_controller.rb", "app/controllers/blog_controller.rb"

      # Models
      m.file "models/blog_post.rb", "app/models/blog_post.rb"

      # Helpers
      m.file "helpers/blog_helper.rb", "app/helpers/blog_helper.rb"

      # Views
      m.directory "app/views/blog"
      m.file "views/index.html.erb", "app/views/blog/index.html.erb"
      m.file "views/details.html.erb", "app/views/blog/details.html.erb"
      m.file "views/feed.rss.builder", "app/views/blog/feed.rss.builder"

      # Migration
      m.migration_template "migrate/create_blog.rb", "db/migrate"

      # Tests
      m.file "test/fixtures/blog_posts.yml", "test/fixtures/blog_posts.yml"
      m.file "test/functional/blog_controller_test.rb", "test/functional/blog_controller_test.rb"
      m.file "test/unit/blog_post_test.rb", "test/unit/blog_post_test.rb"

      # CSS and images
      m.file "assets/blog_styles.css", "public/stylesheets/px_blogger.css"
      m.file "assets/comment_add.gif", "public/images/comment_add.gif"
      m.file "assets/comment.gif", "public/images/comment.gif"

      m.readme "INSTALL"
    end
  end

  def file_name
    "create_blog"
  end

end

Here is a breakdown of what is going on:

• The directory method will create the specified directory if it doesn't exist already.
• The file method will copy the specified file to the given directory.
• The migration_template file will copy the given migration file into the db/migrations folder using the file_name method defined at the bottom of the generator to name the file.
• The readme function prints out the contents of the INSTALL file after the generator script is called. You can use this file to put any extra instructions for the generator.

This is what the file structure looks like for the generator:

lib
\- generators
   \- blog
      \- blog_generator.rb
         templates
         \- assets
            \- blog_styles.css
               comment_add.gif
               comment.gif
            controllers
            \- blog_controller.rb
            helpers
            \- blog_helper.rb
            INSTALL
            migrate
            \- create_blog.rb
            models
            \- blog_post.rb
            test
            \- fixtures
               \- blog_posts.yml
               functional
               \- blog_controller_test.rb
               unit
               \- blog_post_test.rb
            views
            \- index.html.erb
               details.html.erb
               feed.rss.builder
         USAGE

All we need to do to run this generator is call script/generate blog.

Tagged: rails, generators, tutorial