gistfile1.rb

# Enabling order for Radiant extensions migration.
#

# -------------------------------------------------
# Modify environment.rb by putting this AFTER the line with 'config.extensions':

  if ENV.has_key?('CONFIG_EXTENSIONS')
    ::PENDING_EXTENSIONS = config.extensions.clone
    config.extensions = ENV['CONFIG_EXTENSIONS'].split(/[\,\ \:]+/).map{ |x| x.strip.to_sym }
  end

# -------------------------------------------------
# Modify Rakefile by adding:

  def subcall_rake(c_task, extensions_to_load=[])
    rails_env     = ENV['RAILS_ENV'].to_s.empty? ? "" : "RAILS_ENV=" + ENV['RAILS_ENV']  
    rake_call     = defined?(rake_cmd) ? rake_cmd : ENV['SUDO_COMMAND'] || ENV['_'] || Rake.application.name || 'rake'
    enable_trace  = Rake.application.options.trace.nil? ? "" : "--trace"
    config_extensions = extensions_to_load.empty? ? "" : "CONFIG_EXTENSIONS=" + extensions_to_load.join(':')
    sh %{ #{rake_call} #{config_extensions} #{rails_env} #{c_task} #{enable_trace} }
  end

namespace :db do

  namespace :migrate do
    namespace :extensions do

      desc "Migrates database according to needs of installed extensions."      
      task :all_safely do
        # For some extensions order of migration has meaning.
        # Safely assume that each succeeding extension from configuration
        # requires all previously listed extensions loaded to run properly.
        extensions_to_load = []
        exts_orig_dir = File.join(File.dirname(__FILE__), 'vendor', 'extensions')
        exts_bak_dir  = File.join(File.dirname(__FILE__), 'vendor', 'extensions.DB_BOOT2')
        begin
          begin
            FileUtils.rmdir(exts_orig_dir)
          rescue
          end
          FileUtils.mv(exts_orig_dir, exts_bak_dir)
          FileUtils.mkdir(exts_orig_dir, :mode => File.stat(exts_bak_dir).mode)
          ENV['CONFIG_EXTENSIONS'] = "all"
          require File.join(RAILS_ROOT, 'config/environment')
          ::PENDING_EXTENSIONS.each do |extension|
            next if extension == :all
            extension = extension.to_s.strip
            ext_orig = File.join(exts_orig_dir, extension)
            ext_bak = File.join(exts_bak_dir, extension)
            extensions_to_load << extension
            subtask = "radiant:extensions:#{extension}:migrate"
            FileUtils.mv(ext_bak, ext_orig)
            puts "----------------"
            puts "[SAFE MIGRATION]: #{extension}"
            subcall_rake(subtask, extensions_to_load) if Rake::Task.task_defined?(subtask)
          end
        ensure
          extensions_to_load.each do |extension|
            ext_orig = File.join(exts_orig_dir, extension)
            ext_bak = File.join(exts_bak_dir, extension)
            FileUtils.mv(ext_orig, ext_bak)
          end
          FileUtils.rmdir exts_orig_dir
          FileUtils.mv(exts_bak_dir, exts_orig_dir)
        end
        # For the rest extensions just call joint migrate
        # with default set of extensions.
        ENV.delete 'CONFIG_EXTENSIONS'
        subcall_rake 'db:migrate:extensions'
      end

    end # namespace :extensions
  end # namespace :migrate

end # namespace :db


# Usage:
# 
# rake db:migrate:extensions:all_safely