func()

in core/agent_windows.go [166:263]


func (a *amazonSSMAgentService) Execute(args []string, r <-chan svc.ChangeRequest, s chan<- svc.Status) (bool, uint32) {
	log := a.log
	defer func() {
		// recover in case the agent panics
		// this should handle some kind of seg fault errors.
		if msg := recover(); msg != nil {
			log.Errorf("core Agent service crashed with message %v!", msg)
			log.Errorf("Stacktrace:\n%s", debug.Stack())
		}
	}()

	log.Info("Waiting for system state")
	isSysPrepEC, erro := waitForSysPrep(log)
	if !(isSysPrepEC && erro == appconfig.SuccessExitCode) { //returnCode true with success exit code means we can continue to start the agent
		log.Warnf("System not ready, not starting agent: isSysPrepEC %v, erro %v", isSysPrepEC, erro)
		// In this case, svcSpecificEC = sysPrepEC and so we will return it
		return isSysPrepEC, erro
	}
	log.Info("System is ready")

	// notify service controller status is now StartPending
	s <- svc.Status{State: svc.StartPending}

	// start service
	log.Info("Starting up agent subsystem")
	agent, contextLog, err := initializeBasicModules(a.log)
	if err != nil {
		contextLog.Errorf("Failed to start agent. %v", err)
		return true, appconfig.ErrorExitCode
	}

	statusChannels := &contracts.StatusComm{
		TerminationChan: make(chan struct{}, 1),
		DoneChan:        make(chan struct{}, 1),
	}

	startCoreAgent(contextLog, agent, statusChannels)
	contextLog.Info("Notifying windows service manager for agent subsystem start")

	// update service status to Running
	const acceptCmds = svc.AcceptStop | svc.AcceptShutdown
	s <- svc.Status{State: svc.Running, Accepts: acceptCmds}
	contextLog.Info("Windows service manager notified that agent service has started")
	var (
		incomingServiceReq         svc.ChangeRequest
		incomingServiceReqChan     = make(chan svc.ChangeRequest, 1)
		terminateIncomingReqThread = make(chan bool, 1)
	)

	go func() {
	incomingReqLoop:
		for {
			select {
			case <-coreAgentStartupErrChan:
				contextLog.Error("Failed to start core agent startup module")
				statusChannels.DoneChan <- struct{}{}
				incomingServiceReqChan <- svc.ChangeRequest{Cmd: svc.Stop}
			case incomingServiceReq = <-r:
				incomingServiceReqChan <- incomingServiceReq
			case <-terminateIncomingReqThread:
				contextLog.Info("Incoming service request go routine ended")
				break incomingReqLoop
			}
		}
	}()

loop:
	// using an infinite loop to wait for ChangeRequests
	for {
		// block and wait for ChangeRequests
		c := <-incomingServiceReqChan

		// handle ChangeRequest, svc.Pause is not supported
		switch c.Cmd {
		case svc.Interrogate:
			contextLog.Debug("Service received interrogate ChangeRequest")
			s <- c.CurrentStatus
			// Testing deadlock from https://code.google.com/p/winsvc/issues/detail?id=4
			time.Sleep(100 * time.Millisecond)
			s <- c.CurrentStatus
		case svc.Stop:
			statusChannels.TerminationChan <- struct{}{}
			contextLog.Info("Service received stop ChangeRequest")
			break loop
		case svc.Shutdown:
			statusChannels.TerminationChan <- struct{}{}
			contextLog.Info("Service received shutdown ChangeRequest")
			break loop
		default:
			continue loop
		}
	}
	s <- svc.Status{State: svc.StopPending}
	terminateIncomingReqThread <- true
	<-statusChannels.DoneChan
	agent.Stop()
	return false, appconfig.SuccessExitCode
}