func main()

in cmd/zoekt-webserver/main.go [104:219]
94 lines of code
21 McCabe index (conditional complexity)

func main() {
	logDir := flag.String("log_dir", "", "log to this directory rather than stderr.")
	logRefresh := flag.Duration("log_refresh", 24*time.Hour, "if using --log_dir, start writing a new file this often.")

	listen := flag.String("listen", ":6070", "listen on this address.")
	index := flag.String("index", build.DefaultDir, "set index directory to use")
	html := flag.Bool("html", true, "enable HTML interface")
	print := flag.Bool("print", false, "enable local result URLs")
	enablePprof := flag.Bool("pprof", false, "set to enable remote profiling.")
	sslCert := flag.String("ssl_cert", "", "set path to SSL .pem holding certificate.")
	sslKey := flag.String("ssl_key", "", "set path to SSL .pem holding key.")
	hostCustomization := flag.String(
		"host_customization", "",
		"specify host customization, as HOST1=QUERY,HOST2=QUERY")

	templateDir := flag.String("template_dir", "", "set directory from which to load custom .html.tpl template files")
	dumpTemplates := flag.Bool("dump_templates", false, "dump templates into --template_dir and exit.")
	version := flag.Bool("version", false, "Print version number")
	flag.Parse()

	if *version {
		fmt.Printf("zoekt-webserver version %q\n", zoekt.Version)
		os.Exit(0)
	}

	if *dumpTemplates {
		if err := writeTemplates(*templateDir); err != nil {
			log.Fatal(err)
		}
		os.Exit(0)
	}

	if *logDir != "" {
		if fi, err := os.Lstat(*logDir); err != nil || !fi.IsDir() {
			log.Fatalf("%s is not a directory", *logDir)
		}
		// We could do fdup acrobatics to also redirect
		// stderr, but it is simpler and more portable for the
		// caller to divert stderr output if necessary.
		go divertLogs(*logDir, *logRefresh)
	}

	// Tune GOMAXPROCS to match Linux container CPU quota.
	maxprocs.Set()

	if err := os.MkdirAll(*index, 0o755); err != nil {
		log.Fatal(err)
	}

	searcher, err := shards.NewDirectorySearcher(*index)
	if err != nil {
		log.Fatal(err)
	}

	s := &web.Server{
		Searcher: searcher,
		Top:      web.Top,
		Version:  zoekt.Version,
	}

	if *templateDir != "" {
		if err := loadTemplates(s.Top, *templateDir); err != nil {
			log.Fatalf("loadTemplates: %v", err)
		}
	}

	s.Print = *print
	s.HTML = *html

	if *hostCustomization != "" {
		s.HostCustomQueries = map[string]string{}
		for _, h := range strings.SplitN(*hostCustomization, ",", -1) {
			if len(h) == 0 {
				continue
			}
			fields := strings.SplitN(h, "=", 2)
			if len(fields) < 2 {
				log.Fatalf("invalid host_customization %q", h)
			}

			s.HostCustomQueries[fields[0]] = fields[1]
		}
	}

	handler, err := web.NewMux(s)
	if err != nil {
		log.Fatal(err)
	}

	handler.Handle("/metrics", promhttp.Handler())

	if *enablePprof {
		handler.HandleFunc("/debug/pprof/", pprof.Index)
		handler.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
		handler.HandleFunc("/debug/pprof/profile", pprof.Profile)
		handler.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
		handler.HandleFunc("/debug/pprof/trace", pprof.Trace)
		handler.HandleFunc("/debug/requests/", trace.Traces)
		handler.HandleFunc("/debug/events/", trace.Events)
	}

	watchdogAddr := "http://" + *listen
	if *sslCert != "" || *sslKey != "" {
		watchdogAddr = "https://" + *listen
	}
	go watchdog(30*time.Second, watchdogAddr)

	if *sslCert != "" || *sslKey != "" {
		log.Printf("serving HTTPS on %s", *listen)
		err = http.ListenAndServeTLS(*listen, *sslCert, *sslKey, handler)
	} else {
		log.Printf("serving HTTP on %s", *listen)
		err = http.ListenAndServe(*listen, handler)
	}
	log.Printf("ListenAndServe: %v", err)
}