func main()

in maintner/maintnerd/maintnerd.go [73:256]

• 166 lines of code
• 41 McCabe index (conditional complexity)

func main() {
	https.RegisterFlags(flag.CommandLine)
	flag.Parse()
	ctx := context.Background()

	if *dataDir == "" {
		*dataDir = filepath.Join(os.Getenv("HOME"), "var", "maintnerd")
		if *bucket == "" {
			if err := os.MkdirAll(*dataDir, 0755); err != nil {
				log.Fatal(err)
			}
			log.Printf("Storing data in implicit directory %s", *dataDir)
		}
	}
	if *migrateGCSFlag && *bucket == "" {
		log.Fatalf("--bucket flag required with --migrate-disk-to-gcs")
	}

	type storage interface {
		maintner.MutationSource
		maintner.MutationLogger
	}
	var logger storage

	corpus := new(maintner.Corpus)
	switch *config {
	case "":
		// Nothing
	case "devgo":
		dir := godata.Dir()
		if err := os.MkdirAll(dir, 0700); err != nil {
			log.Fatal(err)
		}
		log.Printf("Syncing from https://maintner.golang.org/logs to %s", dir)
		mutSrc := maintner.NewNetworkMutationSource("https://maintner.golang.org/logs", dir)
		for evt := range mutSrc.GetMutations(ctx) {
			if evt.Err != nil {
				log.Fatal(evt.Err)
			}
			if evt.End {
				break
			}
		}
		syncProdToDevMutationLogs()
		log.Printf("Synced from https://maintner.golang.org/logs.")
		setGoConfig()
	case "go":
		if err := gitauth.Init(); err != nil {
			log.Fatalf("gitauth: %v", err)
		}
		setGoConfig()
	case "godata":
		setGodataConfig()
		var err error
		log.Printf("Using godata corpus...")
		corpus, err = godata.Get(ctx)
		if err != nil {
			log.Fatal(err)
		}
	default:
		log.Fatalf("unknown --config=%s", *config)
	}
	if *genMut {
		if *bucket != "" {
			ctx := context.Background()
			gl, err := gcslog.NewGCSLog(ctx, *bucket)
			if err != nil {
				log.Fatalf("newGCSLog: %v", err)
			}
			gl.SetDebug(*debug)
			gl.RegisterHandlers(http.DefaultServeMux)
			if *migrateGCSFlag {
				diskLog := maintner.NewDiskMutationLogger(*dataDir)
				if err := gl.CopyFrom(diskLog); err != nil {
					log.Fatalf("migrate: %v", err)
				}
				log.Printf("Success.")
				return
			}
			logger = gl
		} else {
			logger = maintner.NewDiskMutationLogger(*dataDir)
		}
		corpus.EnableLeaderMode(logger, *dataDir)
	}
	if *debug {
		corpus.SetDebug()
	}
	corpus.SetVerbose(*verbose)

	if *watchGithub != "" {
		if *githubRateLimit > 0 {
			limit := rate.Every(time.Second / time.Duration(*githubRateLimit))
			corpus.SetGitHubLimiter(rate.NewLimiter(limit, *githubRateLimit))
		}
		for _, pair := range strings.Split(*watchGithub, ",") {
			splits := strings.SplitN(pair, "/", 2)
			if len(splits) != 2 || splits[1] == "" {
				log.Fatalf("Invalid github repo: %s. Should be 'owner/repo,owner2/repo2'", pair)
			}
			token, err := getGithubToken(ctx)
			if err != nil {
				log.Fatalf("getting github token: %v", err)
			}
			corpus.TrackGitHub(splits[0], splits[1], token)
		}
	}
	if *watchGerrit != "" {
		for _, project := range strings.Split(*watchGerrit, ",") {
			// token may be empty, that's OK.
			corpus.TrackGerrit(project)
		}
	}

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()
	t0 := time.Now()

	if logger != nil {
		if err := corpus.Initialize(ctx, logger); err != nil {
			// TODO: if Initialize only partially syncs the data, we need to delete
			// whatever files it created, since Github returns events newest first
			// and we use the issue updated dates to check whether we need to keep
			// syncing.
			log.Fatal(err)
		}
		initDur := time.Since(t0)

		runtime.GC()
		var ms runtime.MemStats
		runtime.ReadMemStats(&ms)
		log.Printf("Loaded data in %v. Memory: %v MB (%v bytes)", initDur, ms.HeapAlloc>>20, ms.HeapAlloc)
	}
	if *initQuit {
		return
	}

	if *syncQuit {
		if err := corpus.Sync(ctx); err != nil {
			log.Fatalf("corpus.Sync = %v", err)
		}
		if err := corpus.Check(); err != nil {
			log.Fatalf("post-Sync Corpus.Check = %v", err)
		}
		return
	}

	if *pubsub != "" {
		corpus.StartPubSubHelperSubscribe(*pubsub)
	}

	grpcServer := grpc.NewServer()
	apipb.RegisterMaintnerServiceServer(grpcServer, maintapi.NewAPIService(corpus))
	http.Handle("/apipb.MaintnerService/", grpcServer)

	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		if strings.HasPrefix(r.Header.Get("Content-Type"), "application/grpc") {
			grpcServer.ServeHTTP(w, r)
			return
		}
		if r.URL.Path != "/" {
			http.NotFound(w, r)
			return
		}
		io.WriteString(w, `<html>
<body>
<p>
  This is <a href='https://godoc.org/golang.org/x/build/maintner/maintnerd'>maintnerd</a>,
  the <a href='https://godoc.org/golang.org/x/build/maintner'>maintner</a> server.
  See the <a href='https://godoc.org/golang.org/x/build/maintner/godata'>godata package</a> for
  a client.
</p>
<ul>
   <li><a href='/logs'>/logs</a>
</ul>
</body></html>
`)
	})

	if *genMut {
		go func() { log.Fatalf("Corpus.SyncLoop = %v", corpus.SyncLoop(ctx)) }()
	}
	log.Fatalln(https.ListenAndServe(ctx, http.DefaultServeMux))
}