Example Chef Deploy Revision for Rails 3+

application.rb

app = node[:rails][:app]

rails_base app[:name] do
  ruby_ver app[:ruby_ver]
  gemset app[:gemset]
end

%w{config log pids cached-copy bundle system}.each do |dir|
  directory "#{app[:app_root]}/shared/#{dir}" do
    owner app[:deploy_user]
    group app[:deploy_user]
    mode '0755'
    recursive true
    action :create
  end
end

keys = Chef::EncryptedDataBagItem.load('rails', app[:name])

create_database_config app[:name] do
  app_root node[:rails][:app][:app_root]
  deploy_user node[:rails][:app][:deploy_user]
  databases node[:rails][:app][:db][:databases]
  aliases node[:rails][:app][:db][:aliases]
  passwords keys["database_passwords"]
end

deploy_revision "#{app[:app_root]}" do
  repo app[:repo]
  revision cluster_settings["revision"]
  user app[:deploy_user]
  group app[:deploy_user]
  enable_submodules true
  environment({
    "RAILS_ENV" => app[:environment],
  })
  shallow_clone false

  if node["rails"][app[:name]].attribute?('one_time_action')
    # rollback, deploy, force_deploy
    action node["rails"][app[:name]]["one_time_action"]
    node["rails"][app[:name]].delete('one_time_action')
  else
    action :deploy
  end

  migrate true
  migration_command "/usr/local/rvm/bin/appname_bundle exec rake db:migrate --trace"

  before_migrate do

    template "#{release_path}/config/environments/#{app[:environment]}.rb" do
      source "#{release_path}/config/environments/chef_development.rb.erb"
      local true
      owner app[:deploy_user]
      group app[:deploy_user]
      mode '0400'
      variables(:environment_settings => app[:environment_settings].to_hash)
    end

    rvm_shell "Bundle install and assets precompile" do
      ruby_string "#{app[:ruby_ver]}@#{app[:gemset]}"
      cwd release_path
      user app[:deploy_user]
      group app[:deploy_user]

      # common_groups = %w{development test cucumber}
      # bundle install --deployment --path #{app[:app_root]}/shared/bundle --without #{common_groups.join(' ')}

      code %{
        bundle install --path #{app[:app_root]}/shared/bundle
      }
    end
  end

  before_restart do
   rvm_shell "assets precompile" do
     ruby_string "#{app[:ruby_ver]}@#{app[:gemset]}"
     cwd release_path
     user app[:deploy_user]
     group app[:deploy_user]

     # TODO I could not set the environment via the builtin command. Does not look like it is getting passed to popen4
     # So instead of `environment "RAILS_ENV" => app[:environment]` I have it in the code block
     code %{
       export RAILS_ENV=#{app[:environment]}
       bundle exec rake assets:precompile
     }
   end
 end

  symlink_before_migrate({
    "config/database.yml" => "config/database.yml",
    "config/environments/#{app[:environment]}.rb" => "config/environments/#{app[:environment]}.rb"
  })

  after_restart do
    notify_airbrake release_path do
      environment app[:environment]
      repository app[:repo]
    end
    notify_newrelic release_path do
      environment app[:environment]
    end
  end
end

application_environment.rb

#Used to configure variables for the app per environment (instead of attributes).
#I have since refactored how this works so treat this as example code, aka I
#have not tested this and it is not complete.
#FWIW using libraries in the cookbook to set these variables
#for smaller apps I would keep this in the attributes

app_name = 'yourname'
default = {
  name: app_name
  gemset: app_name
  ruby_ver: 'ruby-1.8.7-p352',
  deploy_user: 'deployer',
  environment: node[:environment],
  #...
}

staging = {
  app_root: '/export/staging/yourname',
  #...
}

case node[:environment]
when "staging"
  rails_attributes = Chef::Mixin::DeepMerge.merge(default, staging)
end

# Don't know why I saved this in a seperate hash before the deep merge...
original_node_attributes = node.default.to_hash
node.default[:rails] = Chef::Mixin::DeepMerge.merge(rails_attributes, original_node_attributes["rails"])

create_database_config.rb

define :create_database_config, :passwords=>{} do

  databases = Hash.new

  params[:databases].each do |db_name|
    if node[:rails][params[:name]][:db].has_key?(db_name)
      values = node[:rails][params[:name]][:db][db_name].to_hash
      if params[:passwords].has_key?(db_name.to_s)
        values["password"] = params[:passwords].fetch(db_name.to_s)
      end
      name = values.has_key?(name) ? values[:name] : db_name
      databases.merge!({ name.to_s => values })
    end
  end

  if params.has_key? :aliases
    params[:aliases].each do |target,source|
      databases[target.to_s] = databases[source.to_s]
    end
  end

  file "#{params[:app_root]}/shared/config/database.yml" do
    owner params[:deploy_user]
    group params[:deploy_user]
    mode '400'
    content databases.to_yaml
  end
end

notify_airbrake.rb

define :notify_airbrake, :name=>nil, :environment=>nil, :repository=>nil do

  script "notifying airbrake of deploy" do
    interpreter "ruby"
    user "deployer"
    cwd params[:name]
    code <<-EOS
    require 'rubygems'
    unless File.exist?("#{params[:name]}/config/initializers/airbrake.rb")
        puts "!!! airbrake.rb not found. Not notifying Airbrake of the deploy !!!"
        exit 0
    end

    # Setup the airbrake api_key
    require 'airbrake'
    require 'airbrake_tasks'
    require "#{params[:name]}/config/initializers/airbrake.rb"

    revision = `cd #{params[:name]} && git rev-parse HEAD`.chomp

    print "Airbrake : "

    AirbrakeTasks.deploy(:rails_env      => '#{params[:environment]}',
                         :scm_revision   => revision,
                         :scm_repository => '#{params[:repository]}',
                         :local_username => 'chef')
    EOS
  end
end

notify_newrelic.rb

define :notify_newrelic, :deploy_path=>nil, :environment=>nil do

  script "notifying new relic of deploy" do
    interpreter "ruby"
    user "deployer"
    cwd params[:name]
    code <<-EOS
      require 'rubygems'

      unless File.exist?("#{params[:name]}/config/newrelic.yml")
          puts "!!! newrelic.yml not found. Not notifying New Relic of the deploy !!!"
          exit 0
      end

      ## When new relic is loaded it automagically loads up its configuration file
      ## And sets the config[:environment]. We are injecting the path to the configuration
      ## file and the environment via ENV variables.
      ENV['APP_ROOT'] = "#{params[:name]}"
      ENV['RAILS_ENV'] = "#{params[:environment]}"
      require 'newrelic_rpm'
      require 'new_relic/command'

      config = NewRelic::Control.instance
      revision = `git rev-parse HEAD`.chomp
      deployment = NewRelic::Command::Deployments.new({:revision  => revision, :user => 'chef'})
      print "New Relic : "
      deployment.run
    EOS
  end

end

rails_base.rb

define :rails_base, :ruby_ver=>nil, :gemset=>nil do
  include_recipe "nodejs"
  package "mysql-client"
  package "libmysqlclient-dev"
  gem_package "newrelic_rpm"
  gem_package "airbrake"

  directory '/export' do
    owner 'root'
    group 'root'
    recursive true
    action :create
    only_if "test -e /export"
  end

  create_deploy_user

  rvm_gemset params[:gemset] do
    ruby_string params[:ruby_ver]
    action :create
  end

  rvm_gem 'bundler' do
    ruby_string "#{params[:ruby_ver]}@#{params[:gemset]}"
  end

  # Creates /usr/local/rvm/bin/appname_bundle
  rvm_wrapper params[:name] do
    ruby_string "#{params[:ruby_ver]}@#{params[:gemset]}"
    binary 'bundle'
  end
end

yourname.json

{
  # Handwritten from memory, probably broken
  "id": "yourname",
  "database_passwords": {
    "staging": "foo"
  }
}

Great!
Have you packaged it any gem?

Or where can I find the cookbook for this?

I have not release this in a gem or cookbook. This should be pretty complete example. Are you looking for more?

Yes, I'ld like to see all the templates and the structure of the data bag as well.

And what is the app server it will use? I mean Unicorn, Nginx, et...

How the attributes will look like along with data_bag item as well?

Hey there!

Updated the code a bit. Hopefully that helped. I have been using one of the unicorn cookbooks (i think from opscode) and apache to serve all of this. I have been separating out the app deployment from the server as we also deploy delay jobs and other systems that need RoR but not unicorn. For example our run_lists kinda look like

• www_front_end = app, app_apache # Want apache and assets
• app_server = app, app_unicorn
• dj_server = app, app_dj

Hopefully this answered some of your questions. I will try to get to others but will be delayed :) Have fun!!

@finack, Thanks for the update and its really helpful.
But a few pieces left out to make it work for me.

First, the following definition to create the database.

create_database_config app[:name] do
  app_root node[:rails][:app][:app_root]
  deploy_user node[:rails][:app][:deploy_user]
  databases node[:rails][:app][:db][:databases]
  aliases node[:rails][:app][:db][:aliases]
  passwords keys["database_passwords"]
end

What would be the structure of the attributes/default.rb file?
Does the following work or I think I need to change the attributes?

default['rails']['app']['app_root'] = "/home/deployer"
default['rails']['railsbp']['db']['railsbp_prod']['encoding'] = "utf8"
default['rails']['railsbp']['db']['railsbp_prod']['reconnect'] = "true"
default['rails']['railsbp']['db']['railsbp_prod']['adapter'] = "mysql2"

And lastly, what that source "#{release_path}/config/environments/chef_development.rb.erb" template looks like?

Yeah, I know I'm aksing a lot. But your help is directing me to the final deploy.

Can you address those queries?