Golang shutdown.BeforeExit函數代碼示例

func main() {
	defer shutdown.Exit()

	apiPort := os.Getenv("PORT")
	if apiPort == "" {
		apiPort = "5000"
	}

	logAddr := flag.String("logaddr", ":3000", "syslog input listen address")
	apiAddr := flag.String("apiaddr", ":"+apiPort, "api listen address")
	flag.Parse()

	a := NewAggregator(*logAddr)
	if err := a.Start(); err != nil {
		shutdown.Fatal(err)
	}
	shutdown.BeforeExit(a.Shutdown)

	listener, err := reuseport.NewReusablePortListener("tcp4", *apiAddr)
	if err != nil {
		shutdown.Fatal(err)
	}

	hb, err := discoverd.AddServiceAndRegister("flynn-logaggregator", *logAddr)
	if err != nil {
		shutdown.Fatal(err)
	}
	shutdown.BeforeExit(func() { hb.Close() })

	shutdown.Fatal(http.Serve(listener, apiHandler(a)))
}

func main() {
	serviceName := os.Getenv("FLYNN_POSTGRES")
	if serviceName == "" {
		serviceName = "postgres"
	}
	singleton := os.Getenv("SINGLETON") == "true"
	password := os.Getenv("PGPASSWORD")

	const dataDir = "/data"
	idFile := filepath.Join(dataDir, "instance_id")
	idBytes, err := ioutil.ReadFile(idFile)
	if err != nil && !os.IsNotExist(err) {
		shutdown.Fatalf("error reading instance ID: %s", err)
	}
	id := string(idBytes)
	if len(id) == 0 {
		id = random.UUID()
		if err := ioutil.WriteFile(idFile, []byte(id), 0644); err != nil {
			shutdown.Fatalf("error writing instance ID: %s", err)
		}
	}

	err = discoverd.DefaultClient.AddService(serviceName, &discoverd.ServiceConfig{
		LeaderType: discoverd.LeaderTypeManual,
	})
	if err != nil && !httphelper.IsObjectExistsError(err) {
		shutdown.Fatal(err)
	}
	inst := &discoverd.Instance{
		Addr: ":5432",
		Meta: map[string]string{pgIdKey: id},
	}
	hb, err := discoverd.DefaultClient.RegisterInstance(serviceName, inst)
	if err != nil {
		shutdown.Fatal(err)
	}
	shutdown.BeforeExit(func() { hb.Close() })

	log := log15.New("app", "postgres")

	pg := NewPostgres(Config{
		ID:           id,
		Singleton:    singleton,
		DataDir:      filepath.Join(dataDir, "db"),
		BinDir:       "/usr/lib/postgresql/9.5/bin/",
		Password:     password,
		Logger:       log.New("component", "postgres"),
		ExtWhitelist: true,
		WaitUpstream: true,
		SHMType:      "posix",
	})
	dd := sd.NewDiscoverd(discoverd.DefaultClient.Service(serviceName), log.New("component", "discoverd"))

	peer := state.NewPeer(inst, id, pgIdKey, singleton, dd, pg, log.New("component", "peer"))
	shutdown.BeforeExit(func() { peer.Close() })

	go peer.Run()
	shutdown.Fatal(ServeHTTP(pg.(*Postgres), peer, hb, log.New("component", "http")))
	// TODO(titanous): clean shutdown of postgres
}

func main() {
	log := logger.New("fn", "main")

	log.Info("creating controller client")
	client, err := controller.NewClient("", os.Getenv("AUTH_KEY"))
	if err != nil {
		log.Error("error creating controller client", "err", err)
		shutdown.Fatal(err)
	}

	log.Info("connecting to postgres")
	db := postgres.Wait(nil, schema.PrepareStatements)

	shutdown.BeforeExit(func() { db.Close() })

	go func() {
		status.AddHandler(func() status.Status {
			_, err := db.ConnPool.Exec("ping")
			if err != nil {
				return status.Unhealthy
			}
			return status.Healthy
		})
		addr := ":" + os.Getenv("PORT")
		hb, err := discoverd.AddServiceAndRegister("controller-worker", addr)
		if err != nil {
			shutdown.Fatal(err)
		}
		shutdown.BeforeExit(func() { hb.Close() })
		shutdown.Fatal(http.ListenAndServe(addr, nil))
	}()

	workers := que.NewWorkerPool(
		que.NewClient(db.ConnPool),
		que.WorkMap{
			"deployment":             deployment.JobHandler(db, client, logger),
			"app_deletion":           app_deletion.JobHandler(db, client, logger),
			"domain_migration":       domain_migration.JobHandler(db, client, logger),
			"release_cleanup":        release_cleanup.JobHandler(db, client, logger),
			"app_garbage_collection": app_garbage_collection.JobHandler(db, client, logger),
		},
		workerCount,
	)
	workers.Interval = 5 * time.Second

	log.Info("starting workers", "count", workerCount, "interval", workers.Interval)
	workers.Start()
	shutdown.BeforeExit(func() { workers.Shutdown() })

	select {} // block and keep running
}

func main() {
	defer shutdown.Exit()

	dsn := &mariadb.DSN{
		Host:     serviceHost + ":3306",
		User:     "flynn",
		Password: os.Getenv("MYSQL_PWD"),
		Database: "mysql",
	}
	db, err := sql.Open("mysql", dsn.String())
	api := &API{db}

	router := httprouter.New()
	router.POST("/databases", httphelper.WrapHandler(api.createDatabase))
	router.DELETE("/databases", httphelper.WrapHandler(api.dropDatabase))
	router.GET("/ping", httphelper.WrapHandler(api.ping))

	port := os.Getenv("PORT")
	if port == "" {
		port = "3000"
	}
	addr := ":" + port

	hb, err := discoverd.AddServiceAndRegister(serviceName+"-api", addr)
	if err != nil {
		shutdown.Fatal(err)
	}
	shutdown.BeforeExit(func() { hb.Close() })

	handler := httphelper.ContextInjector(serviceName+"-api", httphelper.NewRequestLogger(router))
	shutdown.Fatal(http.ListenAndServe(addr, handler))
}

func main() {
	defer shutdown.Exit()

	api := &API{}

	router := httprouter.New()
	router.POST("/databases", api.createDatabase)
	router.DELETE("/databases", api.dropDatabase)
	router.GET("/ping", api.ping)

	port := os.Getenv("PORT")
	if port == "" {
		port = "3000"
	}
	addr := ":" + port

	hb, err := discoverd.AddServiceAndRegister(serviceName+"-api", addr)
	if err != nil {
		shutdown.Fatal(err)
	}
	shutdown.BeforeExit(func() { hb.Close() })

	handler := httphelper.ContextInjector(serviceName+"-api", httphelper.NewRequestLogger(router))
	shutdown.Fatal(http.ListenAndServe(addr, handler))
}

/*
	ish: the Inexusable/Insecure/Internet SHell.
*/
func main() {
	defer shutdown.Exit()

	name := os.Getenv("NAME")
	port := os.Getenv("PORT")
	addr := ":" + port
	if name == "" {
		name = "ish-service"
	}

	l, err := net.Listen("tcp", addr)
	if err != nil {
		shutdown.Fatal(err)
	}
	defer l.Close()

	hb, err := discoverd.AddServiceAndRegister(name, addr)
	if err != nil {
		shutdown.Fatal(err)
	}
	shutdown.BeforeExit(func() { hb.Close() })

	http.HandleFunc("/ish", ish)
	if err := http.Serve(l, nil); err != nil {
		shutdown.Fatal(err)
	}
}

func main() {
	defer shutdown.Exit()

	db := postgres.Wait(&postgres.Conf{
		Service:  serviceName,
		User:     "flynn",
		Password: os.Getenv("PGPASSWORD"),
		Database: "postgres",
	}, nil)
	api := &pgAPI{db}

	router := httprouter.New()
	router.POST("/databases", httphelper.WrapHandler(api.createDatabase))
	router.DELETE("/databases", httphelper.WrapHandler(api.dropDatabase))
	router.GET("/ping", httphelper.WrapHandler(api.ping))

	port := os.Getenv("PORT")
	if port == "" {
		port = "3000"
	}
	addr := ":" + port

	hb, err := discoverd.AddServiceAndRegister(serviceName+"-api", addr)
	if err != nil {
		shutdown.Fatal(err)
	}
	shutdown.BeforeExit(func() { hb.Close() })

	handler := httphelper.ContextInjector(serviceName+"-api", httphelper.NewRequestLogger(router))
	shutdown.Fatal(http.ListenAndServe(addr, handler))
}

func (d *discoverdWrapper) Register() (bool, error) {
	log := logger.New("fn", "discoverd.Register")

	log.Info("registering with service discovery")
	hb, err := discoverd.AddServiceAndRegister(serviceName, d.addr)
	if err != nil {
		log.Error("error registering with service discovery", "err", err)
		return false, err
	}
	shutdown.BeforeExit(func() { hb.Close() })

	selfAddr := hb.Addr()
	log = log.New("self.addr", selfAddr)

	service := discoverd.NewService(serviceName)
	var leaders chan *discoverd.Instance
	var stream stream.Stream
	connect := func() (err error) {
		log.Info("connecting service leader stream")
		leaders = make(chan *discoverd.Instance)
		stream, err = service.Leaders(leaders)
		if err != nil {
			log.Error("error connecting service leader stream", "err", err)
		}
		return
	}
	if err := connect(); err != nil {
		return false, err
	}

	go func() {
	outer:
		for {
			for leader := range leaders {
				if leader == nil {
					// a nil leader indicates there are no instances for
					// the service, ignore and wait for an actual leader
					log.Warn("received nil leader event")
					continue
				}
				log.Info("received leader event", "leader.addr", leader.Addr)
				d.leader <- leader.Addr == selfAddr
			}
			log.Warn("service leader stream disconnected", "err", stream.Err())
			for {
				if err := connect(); err == nil {
					continue outer
				}
				time.Sleep(100 * time.Millisecond)
			}
		}
	}()

	select {
	case isLeader := <-d.leader:
		return isLeader, nil
	case <-time.After(30 * time.Second):
		return false, errors.New("timed out waiting for current service leader")
	}
}

// Run executes the program.
func (m *Main) Run() error {
	m.Logger.Info("running")

	// Read or generate the instance identifier from file.
	id, err := m.readID(filepath.Join(m.DataDir, "instance_id"))
	if err != nil {
		return err
	}
	m.Process.ID = id
	m.Process.DataDir = m.DataDir
	m.Process.Logger = m.Logger.New("component", "process", "id", id)

	// Start process.
	m.Logger.Info("starting process", "id", id)
	if err := m.Process.Start(); err != nil {
		m.Logger.Error("error starting process", "err", err)
		return err
	}

	// Add service to discoverd registry.
	m.Logger.Info("adding service", "name", m.ServiceName)
	if err = m.DiscoverdClient.AddService(m.ServiceName, nil); err != nil && !httphelper.IsObjectExistsError(err) {
		m.Logger.Error("error adding discoverd service", "err", err)
		return err
	}
	inst := &discoverd.Instance{
		Addr: ":" + m.Process.Port,
		Meta: map[string]string{"REDIS_ID": id},
	}

	// Register instance and retain heartbeater.
	m.Logger.Info("registering instance", "addr", inst.Addr, "meta", inst.Meta)
	hb, err := m.DiscoverdClient.RegisterInstance(m.ServiceName, inst)
	if err != nil {
		m.Logger.Error("error registering discoverd instance", "err", err)
		return err
	}
	m.hb = hb
	shutdown.BeforeExit(func() { hb.Close() })

	m.Logger.Info("opening port", "addr", m.Addr)

	// Open HTTP port.
	ln, err := net.Listen("tcp", m.Addr)
	if err != nil {
		m.Logger.Error("error opening port", "err", err)
		return err
	}
	m.ln = ln

	// Initialize and server handler.
	m.Logger.Info("serving http api")
	h := redis.NewHandler()
	h.Process = m.Process
	h.Heartbeater = m.hb
	h.Logger = m.Logger.New("component", "http")
	go func() { http.Serve(ln, h) }()

	return nil
}

func runServer(_ *docopt.Args) error {
	addr := ":" + os.Getenv("PORT")

	db := postgres.Wait(nil, nil)
	if err := dbMigrations.Migrate(db); err != nil {
		return fmt.Errorf("error running DB migrations: %s", err)
	}

	mux := http.NewServeMux()

	repo, err := data.NewFileRepoFromEnv(db)
	if err != nil {
		return err
	}

	hb, err := discoverd.AddServiceAndRegister("blobstore", addr)
	if err != nil {
		return err
	}
	shutdown.BeforeExit(func() { hb.Close() })

	log.Println("Blobstore serving files on " + addr)

	mux.Handle("/", handler(repo))
	mux.Handle(status.Path, status.Handler(func() status.Status {
		if err := db.Exec("SELECT 1"); err != nil {
			return status.Unhealthy
		}
		return status.Healthy
	}))

	h := httphelper.ContextInjector("blobstore", httphelper.NewRequestLogger(mux))
	return http.ListenAndServe(addr, h)
}

func main() {
	log := logger.New("fn", "main")

	log.Info("creating controller client")
	client, err := controller.NewClient("", os.Getenv("AUTH_KEY"))
	if err != nil {
		log.Error("error creating controller client", "err", err)
		shutdown.Fatal()
	}

	log.Info("connecting to postgres")
	db := postgres.Wait("", "")

	log.Info("creating postgres connection pool")
	pgxpool, err := pgx.NewConnPool(pgx.ConnPoolConfig{
		ConnConfig: pgx.ConnConfig{
			Host:     os.Getenv("PGHOST"),
			User:     os.Getenv("PGUSER"),
			Password: os.Getenv("PGPASSWORD"),
			Database: os.Getenv("PGDATABASE"),
		},
		AfterConnect:   que.PrepareStatements,
		MaxConnections: workerCount,
	})
	if err != nil {
		log.Error("error creating postgres connection pool", "err", err)
		shutdown.Fatal()
	}
	shutdown.BeforeExit(func() { pgxpool.Close() })

	workers := que.NewWorkerPool(
		que.NewClient(pgxpool),
		que.WorkMap{
			"deployment":   deployment.JobHandler(db, client, logger),
			"app_deletion": app_deletion.JobHandler(db, client, logger),
		},
		workerCount,
	)
	workers.Interval = 5 * time.Second

	log.Info("starting workers", "count", workerCount, "interval", workers.Interval)
	workers.Start()
	shutdown.BeforeExit(func() { workers.Shutdown() })

	select {} // block and keep running
}

func main() {
	defer shutdown.Exit()

	apiPort := os.Getenv("PORT")
	if apiPort == "" {
		apiPort = "5000"
	}

	logAddr := flag.String("logaddr", ":3000", "syslog input listen address")
	apiAddr := flag.String("apiaddr", ":"+apiPort, "api listen address")
	snapshotPath := flag.String("snapshot", "", "snapshot path")
	flag.Parse()

	a := NewAggregator(*logAddr)

	if *snapshotPath != "" {
		if err := a.ReplaySnapshot(*snapshotPath); err != nil {
			shutdown.Fatal(err)
		}

		shutdown.BeforeExit(func() {
			if err := a.TakeSnapshot(*snapshotPath); err != nil {
				log15.Error("snapshot error", "err", err)
			}
		})
	}

	if err := a.Start(); err != nil {
		shutdown.Fatal(err)
	}
	shutdown.BeforeExit(a.Shutdown)

	listener, err := net.Listen("tcp4", *apiAddr)
	if err != nil {
		shutdown.Fatal(err)
	}

	hb, err := discoverd.AddServiceAndRegister("flynn-logaggregator", *logAddr)
	if err != nil {
		shutdown.Fatal(err)
	}
	shutdown.BeforeExit(func() { hb.Close() })

	shutdown.Fatal(http.Serve(listener, apiHandler(a)))
}

func main() {
	serviceName := os.Getenv("FLYNN_POSTGRES")
	if serviceName == "" {
		serviceName = "postgres"
	}
	singleton := os.Getenv("SINGLETON") == "true"
	password := os.Getenv("PGPASSWORD")

	err := discoverd.DefaultClient.AddService(serviceName, &discoverd.ServiceConfig{
		LeaderType: discoverd.LeaderTypeManual,
	})
	if err != nil && !httphelper.IsObjectExistsError(err) {
		shutdown.Fatal(err)
	}
	inst := &discoverd.Instance{Addr: ":5432"}
	hb, err := discoverd.DefaultClient.RegisterInstance(serviceName, inst)
	if err != nil {
		shutdown.Fatal(err)
	}
	shutdown.BeforeExit(func() { hb.Close() })

	log := log15.New("app", "postgres")

	pg := NewPostgres(Config{
		ID:           inst.ID,
		Singleton:    singleton,
		BinDir:       "/usr/lib/postgresql/9.4/bin/",
		Password:     password,
		Logger:       log.New("component", "postgres"),
		ExtWhitelist: true,
		WaitUpstream: true,
		// TODO(titanous) investigate this:
		SHMType: "sysv", // the default on 9.4, 'posix' is not currently supported in our containers
	})
	dd := NewDiscoverd(discoverd.DefaultClient.Service(serviceName), log.New("component", "discoverd"))

	peer := state.NewPeer(inst, singleton, dd, pg, log.New("component", "peer"))
	shutdown.BeforeExit(func() { peer.Close() })

	go peer.Run()
	shutdown.Fatal(ServeHTTP(pg.(*Postgres), peer, hb, log.New("component", "http")))
	// TODO(titanous): clean shutdown of postgres
}

func main() {
	defer shutdown.Exit()

	grohl.AddContext("app", "controller-scheduler")
	grohl.Log(grohl.Data{"at": "start"})

	go startHTTPServer()

	if period := os.Getenv("BACKOFF_PERIOD"); period != "" {
		var err error
		backoffPeriod, err = time.ParseDuration(period)
		if err != nil {
			shutdown.Fatal(err)
		}
		grohl.Log(grohl.Data{"at": "backoff_period", "period": backoffPeriod.String()})
	}

	cc, err := controller.NewClient("", os.Getenv("AUTH_KEY"))
	if err != nil {
		shutdown.Fatal(err)
	}
	c := newContext(cc, cluster.NewClient())

	c.watchHosts()

	grohl.Log(grohl.Data{"at": "leaderwait"})
	hb, err := discoverd.AddServiceAndRegister("controller-scheduler", ":"+os.Getenv("PORT"))
	if err != nil {
		shutdown.Fatal(err)
	}
	shutdown.BeforeExit(func() { hb.Close() })

	leaders := make(chan *discoverd.Instance)
	stream, err := discoverd.NewService("controller-scheduler").Leaders(leaders)
	if err != nil {
		shutdown.Fatal(err)
	}
	for leader := range leaders {
		if leader.Addr == hb.Addr() {
			break
		}
	}
	if err := stream.Err(); err != nil {
		// TODO: handle discoverd errors
		shutdown.Fatal(err)
	}
	stream.Close()
	// TODO: handle demotion

	grohl.Log(grohl.Data{"at": "leader"})

	// TODO: periodic full cluster sync for anti-entropy
	c.watchFormations()
}

func NewDiscoverdManager(backend Backend, mux *logmux.LogMux, hostID, publishAddr string) *DiscoverdManager {
	d := &DiscoverdManager{
		backend: backend,
		mux:     mux,
		inst: &discoverd.Instance{
			Addr: publishAddr,
			Meta: map[string]string{"id": hostID},
		},
	}
	shutdown.BeforeExit(d.Close)
	return d
}