DZone Snippets: switchtower code

deploy your rails apps on edge rails

technoweenie (Rick Olson) — Tue, 07 Feb 2006 11:07:28 GMT

lib/tasks/rails.rake



desc "Checks out rails"

task :init do

  ENV['SHARED_PATH']  = '../../shared' unless ENV['SHARED_PATH']

  ENV['RAILS_PATH'] ||= File.join(ENV['SHARED_PATH'], 'rails')

 

  checkout_path = File.join(ENV['RAILS_PATH'], 'trunk')

  export_path   = "#{ENV['RAILS_PATH']}/rev_#{ENV['REVISION']}"

  symlink_path  = 'vendor/rails'



  # do we need to checkout the file?

  unless File.exists?(checkout_path)

    puts 'setting up rails trunk'    

    get_framework_for checkout_path do |framework|

      system "svn co http://dev.rubyonrails.org/svn/rails/trunk/#{framework}/lib #{checkout_path}/#{framework}/lib --quiet"

    end

  end



  # do we need to export the revision?

  unless File.exists?(export_path)

    puts "setting up rails rev #{ENV['REVISION']}"

    get_framework_for export_path do |framework|

      system "svn up #{checkout_path}/#{framework}/lib -r #{ENV['REVISION']} --quiet"

      system "svn export #{checkout_path}/#{framework}/lib #{export_path}/#{framework}/lib"

    end

  end



  puts 'linking rails'

  rm_rf   symlink_path

  mkdir_p symlink_path



  get_framework_for symlink_path do |framework|

    ln_s File.expand_path("#{export_path}/#{framework}/lib"), "#{symlink_path}/#{framework}/lib"

  end

end



def get_framework_for(*paths)

  %w( railties actionpack activerecord actionmailer activesupport actionwebservice ).each do |framework|

    paths.each { |path| mkdir_p "#{path}/#{framework}" }

    yield framework

  end

end

Switchtower recipe code:



set :rails_version, 3517

desc "Checks out rails rev ##{rails_version}"

task :after_symlink do

  run <<-CMD

    cd #{current_release} &&

    rake init REVISION=#{rails_version} RAILS_PATH=/home/username/projects/rails

  CMD

end

freeze_edge for switchtower deployments

technoweenie (Rick Olson) — Sat, 05 Nov 2005 05:14:43 GMT

I run this rake task in the after_symlink event of switchtower to set up the newly deployed app's config files. I rewrote the freeze_edge task to be a little more efficient:

1. checks out rails trunk to shared/rails/trunk if needed
2. updates rails trunk to revision used by the app
3. exports that revision to shared/rails/rev_xxxx
4. links that revision to current/vendor/rails

This way, my app only has a single checkout of the rails trunk. Multiple deployments do not checkout fresh copies, but update to the desired revision and export. If you make multiple deployments using the same rails revision, then only the symlink action is performed. This speeds the task up considerably, and conserves disk space and network traffic.

Set rails version in deploy.rb:
set :rails_version, 2871

Create after_symlink task:

desc "Checks out rails rev ##{rails_version}"

task :after_symlink do

  run "cd #{current_release} && rake init SHARED_PATH=#{shared_path} CURRENT_RELEASE=#{current_release} REVISION=#{rails_version}"

end

init task:

desc "Performs an export of the rails trunk"

task :init do

  return unless ENV['SHARED_PATH'] and ENV['CURRENT_RELEASE']

  puts 'copying files...'

  cp "#{ENV['SHARED_PATH']}/database.yml",  "#{ENV['CURRENT_RELEASE']}/config"

  cp "#{ENV['SHARED_PATH']}/dispatch.fcgi", "#{ENV['CURRENT_RELEASE']}/public"



  puts 'setting permissions...'

  chmod 0600, "#{ENV['CURRENT_RELEASE']}/config/database.yml"

  chmod 0700, "#{ENV['CURRENT_RELEASE']}/public/dispatch.fcgi"

  

  checkout_path = "#{ENV['SHARED_PATH']}/rails/trunk"

  export_path = "#{ENV['SHARED_PATH']}/rails/rev_#{ENV['REVISION']}"

  symlink_path = "#{ENV['CURRENT_RELEASE']}/vendor/rails"



  # do we need to checkout the file?

  unless File.exists?(checkout_path)

    puts 'setting up rails trunk'    

    get_framework_for checkout_path do |framework|

      system "svn co http://dev.rubyonrails.org/svn/rails/trunk/#{framework}/lib #{checkout_path}/#{framework}/lib --quiet"

    end

  end



  # do we need to export the revision?

  unless File.exists?(export_path)

    puts "setting up rails rev #{ENV['REVISION']}"

    get_framework_for export_path, symlink_path do |framework|

      system "svn up #{checkout_path}/#{framework}/lib -r #{ENV['REVISION']} --quiet"

      system "svn export #{checkout_path}/#{framework}/lib #{export_path}/#{framework}/lib"

    end

  end



  puts 'linking rails'

  rm_rf   "vendor/rails"

  mkdir_p "vendor/rails"



  get_framework_for checkout_path, export_path, symlink_path do |framework|

    ln_s File.expand_path("#{export_path}/#{framework}/lib"), "#{ENV['CURRENT_RELEASE']}/vendor/rails/#{framework}/lib"

  end

end



def get_framework_for(*paths)

  %w( railties actionpack activerecord actionmailer activesupport actionwebservice ).each do |framework|

    paths.each { |path| mkdir_p "#{path}/#{framework}" }

    yield framework

  end

end

restart rails app in switchtower on textdrive

technoweenie (Rick Olson) — Sat, 05 Nov 2005 05:06:56 GMT

You'll have to override the standard Switchtower restart task if you don't have sudo access:

desc "Restart the FCGI processes on the app server."

task :restart, :roles => :app do

  run "ruby #{current_path}/script/process/reaper"

end

manual reaping of fcgi processes

technoweenie (Rick Olson) — Wed, 07 Sep 2005 01:18:57 GMT

These are the signals that SwitchTower's reaper uses:

# reload

kill -s HUP @pid



# graceful

kill -s TERM @pid



# kill

kill -9 @pid



# usr1

kill -s USR1 @pid

checkout rails and apply patches with a rake task

technoweenie (Rick Olson) — Tue, 23 Aug 2005 00:05:04 GMT

see my blog post about this...



desc "Performs an export of the rails trunk"

task :rails_export => :environment do

  FileUtils.rm_rf "#{RAILS_ROOT}/vendor/rails"

  puts 'exporting... ' + ENV["VERSION"].to_s 

  `svn export http://dev.rubyonrails.org/svn/rails/trunk#{ENV["VERSION"] ? "@#{ENV['VERSION']}" : ""} #{RAILS_ROOT}/vendor/rails`

  puts 'applying patches...'

  FileList[File.expand_path("#{RAILS_ROOT}/config/diffs/*.diff")].sort.each do |diff_file|

    %x{cd #{File.expand_path("#{RAILS_ROOT}/vendor/rails")} && cat #{File.expand_path(diff_file)} | patch -p0}

  end

end

Does an svn export from rails. Provide a revision if you don't want to check out the latest. It then applies patches in config/diffs in alphabetical order.

rake rails_export VERSION=2000

Here is a SwitchTower recipe to perform this action automatically:



set :rails_version, '2031' # custom ST variable



desc "Checks out rails rev ##{rails_version}"

task :after_symlink do

  run "cd #{current_release} && rake rails_export VERSION=#{rails_version}"

end