A little more about Stager¶

Stager の位置¶

Stager の仕事¶

• 概要
  • デプロイ時にインストーラーを作成する

デプロイ時にインストーラーを作成する¶

• やり方
  1. Stagerは仕事をTaskとして受け取る
     • VCAP::Stager::Server#run
       • VCAP::Stager::Server#setup_channels
         • VCAP::Stager::Server::Channel#initialize
         • VCAP::Stager::Server::Channel#open
  2. NATSの'vcap.stager.#{qn}'(既定値は['staging'] )にTaskを受信すると，
     VCAP::Stager::Server#add_task を経由して，
     1. まず VCAP::Stager::Task#decode が呼ばれる
        • Taskの内容はこんな感じ
          

                VCAP::Stager::Task.new(dec_msg['app_id'],
                                       dec_msg['properties'],
                                       dec_msg['download_uri'],
                                       dec_msg['upload_uri'],
                                       dec_msg['notify_subj'])
          

          
          

            # @param app_id Integer Globally unique id for app
            # @param props Hash App properties. Keys are
            # :runtime => Application runtime name
            # :framework => Application framework name
            # :environment => Applications environment variables.
            # Hash of NAME => VALUE
            # :services => Services bound to app
            # :resources => Resource limits
            # @param download_uri String Where the stager can fetch the zipped application from.
            # @param upload_uri String Where the stager should PUT the gzipped droplet
            # @param notify_subj String NATS subject that the stager will publish the result to.
            def initialize(app_id, props, download_uri, upload_uri, notify_subj, opts={})
            ..
          

     2. さらに VCAP::Stager::TaskManager#add_task を経由して以下が呼び出される
        • VCAP::Stager::TaskManager#start_task
          • VCAP::Stager::Task#perform
            • VCAP::Stager::Task#create_staging_dir
            • VCAP::Stager::Task#download_app
            • VCAP::Stager::Task#run_staging_plugin ←ここを以下(◎)で詳解
            • VCAP::Stager::Task#upload_droplet

◎run_staging_plugin 詳解

• VCAP::Stager::Task#run_staging_plugin (再掲)
  

      StagingPlugin::Config.to_file(plugin_config, plugin_config_path)
      cmd = "#{@ruby_path} #{@run_plugin_path} #{@app_props['framework']} #{plugin_config_path}" 
  
      @vcap_logger.debug("Running staging command: '#{cmd}'")
      res = run_logged(cmd, 0, @max_staging_duration)
  

  • VCAP::Stager::Task#run_logged
    • VCAP::Stager::Util.run_command
      • run_plugin スクリプト
        

        plugin_name, config_path = ARGV
        
        klass = StagingPlugin.load_plugin_for(plugin_name)  # <= plungin_name から対象プラグインのクラスを作成
        plugin = klass.from_file(config_path)  # <= 対象プラグインのクラスからインスタンスを作成
        plugin.stage_application <= 対象プラグインのstage_applicationメソッドを実行
        

        
        以下Rails3Pluginを例に
        • Rails3Plugin#stage_application
          • create_app_directories <= StagingPlugin#create_app_directories
          • copy_source_files <= StagingPlugin#copy_source_files
          • stage_console
          • compile_gems <= GemfileSupport#compile_gems
          • configure_database <= RailsDatabaseSupport#configure_database
          • install_autoconfig_gem <= RubyAutoConfig#install_autoconfig_gem
          • setup_autoconfig_script <= ?
          • create_asset_plugin <= ?
          • create_startup_script <= StagingPlugin#create_startup_script
          • Rails3Plugin#startup_script
          • create_stop_script <= StagingPlugin#create_stop_script
          • Rails3Plugin#stop_script

Interfaces¶

→ http://apidocs.cloudfoundry.com/

In(→Out)¶

In¶

Out¶

(参考)初期値一覧¶

• 設定ファイル
  TBF
• コンストラクター
  • VCAP::Stager::Task#initialize