func()

in cmd/ops_agent_uap_plugin/service_windows.go [80:160]
62 lines of code
10 McCabe index (conditional complexity)

func (ps *OpsAgentPluginServer) Start(ctx context.Context, msg *pb.StartRequest) (*pb.StartResponse, error) {
	ps.mu.Lock()
	if ps.cancel != nil {
		log.Printf("The Ops Agent plugin is started already, skipping the current request")
		ps.mu.Unlock()
		return &pb.StartResponse{}, nil
	}
	log.Printf("Received a Start request: %s. Starting the Ops Agent", msg)

	pContext, cancel := context.WithCancel(context.Background())
	ps.cancel = cancel
	ps.mu.Unlock()

	// Detect conflicting installations.
	preInstalledAgents, err := findPreExistentAgents(&windowsServiceManager{}, AgentWindowsServiceName)
	if len(preInstalledAgents) != 0 || err != nil {
		ps.Stop(ctx, &pb.StopRequest{Cleanup: false})
		log.Printf("Start() failed: %s", err)
		return nil, status.Error(9, err.Error()) // FailedPrecondition
	}

	// Calculate plugin install and state dirs.
	pluginInstallDir, err := osext.ExecutableFolder()
	if err != nil {
		ps.Stop(ctx, &pb.StopRequest{Cleanup: false})
		log.Printf("Start() failed, because it cannot determine the plugin install location: %s", err)
		return nil, status.Error(13, err.Error()) // Internal
	}

	pluginStateDir := msg.GetConfig().GetStateDirectoryPath()
	if pluginStateDir == "" {
		pluginStateDir = DefaultPluginStateDirectory
	}
	log.Printf("Determined pluginInstallDir: %v, and pluginStateDir: %v", pluginInstallDir, pluginStateDir)

	// Create a windows Event logger. This is used to log generated subagent configs, and health check results.
	windowsEventLogger, err := createWindowsEventLogger()
	if err != nil {
		ps.Stop(ctx, &pb.StopRequest{Cleanup: false})
		log.Printf("Start() failed, because it failed to create Windows event logger: %s", err)
		return nil, status.Error(13, err.Error()) // Internal
	}

	// Receive config from the Start request and write it to the Ops Agent config file.
	if err := writeCustomConfigToFile(msg, OpsAgentConfigLocationWindows); err != nil {
		ps.Stop(ctx, &pb.StopRequest{Cleanup: false})
		windowsEventLogger.Close()
		log.Printf("Start() failed, because it failed to write the custom Ops Agent config to file: %s", err)
		return nil, status.Errorf(13, "failed to write the custom Ops Agent config to file: %s", err) // Internal
	}

	// Subagents config validation and generation.
	if err := generateSubAgentConfigs(ctx, OpsAgentConfigLocationWindows, pluginStateDir, windowsEventLogger); err != nil {
		ps.Stop(ctx, &pb.StopRequest{Cleanup: false})
		windowsEventLogger.Close()
		log.Printf("Start() failed at the subagent config validation and generation step: %s", err)
		return nil, status.Error(9, err.Error()) // FailedPrecondition
	}

	// Trigger Healthchecks.
	healthCheckFileLogger := healthchecks.CreateHealthChecksLogger(filepath.Join(pluginStateDir, LogsDirectory))
	runHealthChecks(healthCheckFileLogger, windowsEventLogger)

	// Create a Windows Job object and stores its handle, to ensure that all child processes are killed when the parent process exits.
	_, err = createWindowsJobHandle()
	if err != nil {
		ps.Stop(ctx, &pb.StopRequest{Cleanup: false})
		windowsEventLogger.Close()
		log.Printf("Start() failed, because it failed to create a Windows Job object: %s", err)
		return nil, status.Error(13, err.Error()) // Internal
	}

	cancelFunc := func() {
		ps.Stop(ctx, &pb.StopRequest{Cleanup: false})
		windowsEventLogger.Close()
	}

	go runSubagents(pContext, cancelFunc, pluginInstallDir, pluginStateDir, runSubAgentCommand, ps.runCommand)

	return &pb.StartResponse{}, nil
}