func main()

in cmd/telegraf/telegraf.go [359:505]
128 lines of code
28 McCabe index (conditional complexity)

func main() {
	flag.Var(&fConfigs, "config", "configuration file to load")
	flag.Var(&fConfigDirs, "config-directory", "directory containing additional *.conf files")

	flag.Usage = func() { usageExit(0) }
	flag.Parse()
	args := flag.Args()

	sectionFilters, inputFilters, outputFilters := []string{}, []string{}, []string{}
	if *fSectionFilters != "" {
		sectionFilters = strings.Split(":"+strings.TrimSpace(*fSectionFilters)+":", ":")
	}
	if *fInputFilters != "" {
		inputFilters = strings.Split(":"+strings.TrimSpace(*fInputFilters)+":", ":")
	}
	if *fOutputFilters != "" {
		outputFilters = strings.Split(":"+strings.TrimSpace(*fOutputFilters)+":", ":")
	}

	aggregatorFilters, processorFilters := []string{}, []string{}
	if *fAggregatorFilters != "" {
		aggregatorFilters = strings.Split(":"+strings.TrimSpace(*fAggregatorFilters)+":", ":")
	}
	if *fProcessorFilters != "" {
		processorFilters = strings.Split(":"+strings.TrimSpace(*fProcessorFilters)+":", ":")
	}

	logger.SetupLogging(logger.LogConfig{})

	// Configure version
	if err := internal.SetVersion(version); err != nil {
		log.Println("Telegraf version already configured to: " + internal.Version())
	}

	// Load external plugins, if requested.
	if *fPlugins != "" {
		log.Printf("I! Loading external plugins from: %s", *fPlugins)
		if err := goplugin.LoadExternalPlugins(*fPlugins); err != nil {
			log.Fatal("E! " + err.Error())
		}
	}

	if *pprofAddr != "" {
		go func() {
			pprofHostPort := *pprofAddr
			parts := strings.Split(pprofHostPort, ":")
			if len(parts) == 2 && parts[0] == "" {
				pprofHostPort = fmt.Sprintf("localhost:%s", parts[1])
			}
			pprofHostPort = "http://" + pprofHostPort + "/debug/pprof"

			log.Printf("I! Starting pprof HTTP server at: %s", pprofHostPort)

			if err := http.ListenAndServe(*pprofAddr, nil); err != nil {
				log.Fatal("E! " + err.Error())
			}
		}()
	}

	if len(args) > 0 {
		switch args[0] {
		case "version":
			fmt.Println(formatFullVersion())
			return
		case "config":
			config.PrintSampleConfig(
				sectionFilters,
				inputFilters,
				outputFilters,
				aggregatorFilters,
				processorFilters,
			)
			return
		}
	}

	// switch for flags which just do something and exit immediately
	switch {
	case *fDeprecationList:
		c := config.NewConfig()
		infos := c.CollectDeprecationInfos(
			inputFilters,
			outputFilters,
			aggregatorFilters,
			processorFilters,
		)
		//nolint:revive // We will notice if Println fails
		fmt.Println("Deprecated Input Plugins: ")
		c.PrintDeprecationList(infos["inputs"])
		//nolint:revive // We will notice if Println fails
		fmt.Println("Deprecated Output Plugins: ")
		c.PrintDeprecationList(infos["outputs"])
		//nolint:revive // We will notice if Println fails
		fmt.Println("Deprecated Processor Plugins: ")
		c.PrintDeprecationList(infos["processors"])
		//nolint:revive // We will notice if Println fails
		fmt.Println("Deprecated Aggregator Plugins: ")
		c.PrintDeprecationList(infos["aggregators"])
		return
	case *fOutputList:
		fmt.Println("Available Output Plugins: ")
		names := make([]string, 0, len(outputs.Outputs))
		for k := range outputs.Outputs {
			names = append(names, k)
		}
		sort.Strings(names)
		for _, k := range names {
			fmt.Printf("  %s\n", k)
		}
		return
	case *fInputList:
		fmt.Println("Available Input Plugins:")
		names := make([]string, 0, len(inputs.Inputs))
		for k := range inputs.Inputs {
			names = append(names, k)
		}
		sort.Strings(names)
		for _, k := range names {
			fmt.Printf("  %s\n", k)
		}
		return
	case *fVersion:
		fmt.Println(formatFullVersion())
		return
	case *fSampleConfig:
		config.PrintSampleConfig(
			sectionFilters,
			inputFilters,
			outputFilters,
			aggregatorFilters,
			processorFilters,
		)
		return
	case *fUsage != "":
		err := config.PrintInputConfig(*fUsage)
		err2 := config.PrintOutputConfig(*fUsage)
		if err != nil && err2 != nil {
			log.Fatalf("E! %s and %s", err, err2)
		}
		return
	}

	run(
		inputFilters,
		outputFilters,
	)
}