Deploying a Merb application with the RailsMachine gem

Feb 07, 2009

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]
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
# =============================================================================
# =============================================================================
# Modify these values to execute tasks on a different server.
role :web, domain
role :app, domain
role :db, domain, :primary => true
role :scm, domain
# =============================================================================
# =============================================================================
set :app_server, :passenger # :mongrel or :passenger
# =============================================================================
# =============================================================================
set :scm, :git # :subversion or :git
set :repository, "git@github.com:travisr/#{application}.git"
# =============================================================================
# =============================================================================
# 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"
# 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"

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: merbpassengercapistranorails machinetutorial