func reloadLoop()

in cmd/telegraf/telegraf.go [116:286]
153 lines of code
36 McCabe index (conditional complexity)

func reloadLoop(stop chan struct{}, s service.Service) {
	defer func() {
		if service.Interactive() {
			os.Exit(0)
		}
		return
	}()
	reload := make(chan bool, 1)
	reload <- true
	for <-reload {
		reload <- false
		flag.Parse()
		args := flag.Args()

		var inputFilters []string
		if *fInputFilters != "" {
			inputFilter := strings.TrimSpace(*fInputFilters)
			inputFilters = strings.Split(":"+inputFilter+":", ":")
		}
		var outputFilters []string
		if *fOutputFilters != "" {
			outputFilter := strings.TrimSpace(*fOutputFilters)
			outputFilters = strings.Split(":"+outputFilter+":", ":")
		}
		var aggregatorFilters []string
		if *fAggregatorFilters != "" {
			aggregatorFilter := strings.TrimSpace(*fAggregatorFilters)
			aggregatorFilters = strings.Split(":"+aggregatorFilter+":", ":")
		}
		var processorFilters []string
		if *fProcessorFilters != "" {
			processorFilter := strings.TrimSpace(*fProcessorFilters)
			processorFilters = strings.Split(":"+processorFilter+":", ":")
		}

		if len(args) > 0 {
			switch args[0] {
			case "version":
				fmt.Printf("Telegraf v%s (git: %s %s)\n", version, branch, commit)
				return
			case "config":
				config.PrintSampleConfig(
					inputFilters,
					outputFilters,
					aggregatorFilters,
					processorFilters,
				)
				return
			}
		}

		// switch for flags which just do something and exit immediately
		switch {
		case *fOutputList:
			fmt.Println("Available Output Plugins:")
			for k, _ := range outputs.Outputs {
				fmt.Printf("  %s\n", k)
			}
			return
		case *fInputList:
			fmt.Println("Available Input Plugins:")
			for k, _ := range inputs.Inputs {
				fmt.Printf("  %s\n", k)
			}
			return
		case *fVersion:
			fmt.Printf("Telegraf v%s (git: %s %s)\n", version, branch, commit)
			return
		case *fSampleConfig:
			config.PrintSampleConfig(
				inputFilters,
				outputFilters,
				aggregatorFilters,
				processorFilters,
			)
			return
		case *fUsage != "":
			if err := config.PrintInputConfig(*fUsage); err != nil {
				if err2 := config.PrintOutputConfig(*fUsage); err2 != nil {
					log.Fatalf("E! %s and %s", err, err2)
				}
			}
			return
		}

		// If no other options are specified, load the config file and run.
		c := config.NewConfig()
		c.OutputFilters = outputFilters
		c.InputFilters = inputFilters
		err := c.LoadConfig(*fConfig)
		if err != nil {
			log.Fatal("E! " + err.Error())
		}

		if *fConfigDirectory != "" {
			err = c.LoadDirectory(*fConfigDirectory)
			if err != nil {
				log.Fatal("E! " + err.Error())
			}
		}
		if len(c.Outputs) == 0 {
			log.Fatalf("E! Error: no outputs found, did you provide a valid config file?")
		}
		if len(c.Inputs) == 0 {
			log.Fatalf("E! Error: no inputs found, did you provide a valid config file?")
		}

		ag, err := agent.NewAgent(c)
		if err != nil {
			log.Fatal("E! " + err.Error())
		}

		// Setup logging
		logger.SetupLogging(
			ag.Config.Agent.Debug || *fDebug,
			ag.Config.Agent.Quiet || *fQuiet,
			ag.Config.Agent.Logfile,
		)

		if *fTest {
			err = ag.Test()
			if err != nil {
				log.Fatal("E! " + err.Error())
			}
			return
		}

		err = ag.Connect()
		if err != nil {
			log.Fatal("E! " + err.Error())
		}

		shutdown := make(chan struct{})
		signals := make(chan os.Signal)
		signal.Notify(signals, os.Interrupt, syscall.SIGHUP)
		go func() {
			select {
			case sig := <-signals:
				if sig == os.Interrupt {
					close(shutdown)
				}
				if sig == syscall.SIGHUP {
					log.Printf("I! Reloading Telegraf config\n")
					<-reload
					reload <- true
					close(shutdown)
				}
			case <-stop:
				close(shutdown)
			}
		}()

		log.Printf("I! Starting Telegraf (version %s)\n", version)
		log.Printf("I! Loaded outputs: %s", strings.Join(c.OutputNames(), " "))
		log.Printf("I! Loaded inputs: %s", strings.Join(c.InputNames(), " "))
		log.Printf("I! Tags enabled: %s", c.ListTags())

		if *fPidfile != "" {
			f, err := os.Create(*fPidfile)
			if err != nil {
				log.Fatalf("E! Unable to create pidfile: %s", err)
			}

			fmt.Fprintf(f, "%d\n", os.Getpid())

			f.Close()
		}

		ag.Run(shutdown)
	}
}