Apache Twill Flows

gistfile1.txt

Apache Twill Launch Flow
====================

HelloWorld
  TwillRunnerService = new YarnTwillRunnerService
  YarnTwillRunnerService.start
     YarnTwillRunnerService.watchLiveServices
   YarnTwillRunnerService.prepare
      YarnTwillPreparer.start
          YarnAppClient.createLauncher       -> This will be instance of ApplicationMasterProcessLauncher
           Create Callable to be passed to ControllerFactory to create YarnTwillController that will call ApplicationMasterProcessLauncher.launch            
               Add java command to execute in the container through ProcessLauncher
           YarnTwillController.start                

YarnTwillController.start
  YarnTwillController.doStartup
    Callable<ProcessController>.call    -> See YarnTwillPreparer class for
                                           Callable<ProcessController<YarnApplicationReport>> submitTask 
      ProcessLauncher.prepareLaunch
      ProcessLauncher.launch
        ApplicationMasterProcessLauncher.doLaunch
          ApplicationSubmitter.submit
            YarnClient.submitApplication 


ApplicationMasterMain.main
  ServiceMain.doMain
    Services.chainStart
      ApplicationMasterService.start
         ApplicationMasterService.doRun
           YarnAMClient.AllocateHandler
              ApplicationMasterService.launchRunnables
                RunningContainers.start(TwillContainerLauncher)
                  TwillContainerLauncher.start ( TwillContainerMain )  -> Main class for container. 
                                                                          start method will return instance of
                                                                          TwillContainerController
                      ProcessController.addCommand       -> Will return instance of PrepareLaunchContext to 
                                                            start TwillLauncher which will run TwillContainerMain
                      ProcessLauncher.launch     ->  Returns instance of ProcessController
                        RunnableProcessLauncher.doLaunch
                      TwillContainerControllerImpl.start ( ProcessController )



RunningContainers.handleCompleted
      
YarnTwillController.createStatusPollingRunnable	-> Check status of application


Apache Twill Message Flow
=====================

TwillRunnerService.lookup
  YarnTwilRunnerService

YarnTwillController.sendCommand(runnableName, Command)
  AbstractZKServiceController.sendCommand
    AbstractZKServiceController.sendMessage