func main()

in sandbox/sandbox.go [110:168]
52 lines of code
9 McCabe index (conditional complexity)

func main() {
	flag.Parse()
	if *mode == "contained" {
		runInGvisor()
		panic("runInGvisor didn't exit")
	}
	if flag.NArg() != 0 {
		flag.Usage()
		os.Exit(1)
	}
	log.Printf("Go playground sandbox starting.")

	readyContainer = make(chan *Container)
	runSem = make(chan struct{}, *numWorkers)
	go handleSignals()

	mux := http.NewServeMux()

	gr, err := metrics.GCEResource("go-playground-sandbox")
	if err != nil && metadata.OnGCE() {
		log.Printf("metrics.GceService(%q) = _, %v, wanted no error.", "go-playground-sandbox", err)
	}
	if ms, err := metrics.NewService(gr, views); err != nil {
		log.Printf("Failed to initialize metrics: metrics.NewService() = _, %v, wanted no error", err)
	} else {
		mux.Handle("/statusz", ochttp.WithRouteTag(ms, "/statusz"))
		defer ms.Stop()
	}

	if out, err := exec.Command("docker", "version").CombinedOutput(); err != nil {
		log.Fatalf("failed to connect to docker: %v, %s", err, out)
	}
	if *dev {
		log.Printf("Running in dev mode; container published to host at: http://localhost:8080/")
		log.Printf("Run a binary with: curl -v --data-binary @/home/bradfitz/hello http://localhost:8080/run\n")
	} else {
		if out, err := exec.Command("docker", "pull", *container).CombinedOutput(); err != nil {
			log.Fatalf("error pulling %s: %v, %s", *container, err, out)
		}
		log.Printf("Listening on %s", *listenAddr)
	}

	mux.Handle("/health", ochttp.WithRouteTag(http.HandlerFunc(healthHandler), "/health"))
	mux.Handle("/healthz", ochttp.WithRouteTag(http.HandlerFunc(healthHandler), "/healthz"))
	mux.Handle("/", ochttp.WithRouteTag(http.HandlerFunc(rootHandler), "/"))
	mux.Handle("/run", ochttp.WithRouteTag(http.HandlerFunc(runHandler), "/run"))

	makeWorkers()
	go internal.PeriodicallyDo(context.Background(), 10*time.Second, func(ctx context.Context, _ time.Time) {
		countDockerContainers(ctx)
	})

	trace.ApplyConfig(trace.Config{DefaultSampler: trace.NeverSample()})
	httpServer = &http.Server{
		Addr:    *listenAddr,
		Handler: &ochttp.Handler{Handler: mux},
	}
	log.Fatal(httpServer.ListenAndServe())
}