Golang atomic.LoadInt32函數代碼示例

// update the reader ready state, updating each connection as appropriate
func (q *Reader) SetMaxInFlight(maxInFlight int) {
	if atomic.LoadInt32(&q.stopFlag) == 1 {
		return
	}

	if maxInFlight > MaxReadyCount {
		log.Printf("WARNING: tried to SetMaxInFlight() > %d, truncating...", MaxReadyCount)
		maxInFlight = MaxReadyCount
	}

	if q.maxInFlight == maxInFlight {
		return
	}

	q.maxInFlight = maxInFlight
	for _, c := range q.nsqConnections {
		if atomic.LoadInt32(&c.stopFlag) == 1 {
			continue
		}
		s := q.ConnectionMaxInFlight()
		if q.VerboseLogging {
			log.Printf("[%s] RDY %d", c, s)
		}
		atomic.StoreInt64(&c.rdyCount, int64(s))
		err := c.sendCommand(Ready(s))
		if err != nil {
			handleError(q, c, fmt.Sprintf("[%s] error reading response %s", c, err.Error()))
		}
	}
}

// Ensure that the mock's Tick channel sends at the correct time.
func TestMock_Tick(t *testing.T) {
	var n int32
	clock := NewMock()

	// Create a channel to increment every 10 seconds.
	go func() {
		tick := clock.Tick(10 * time.Second)
		for {
			<-tick
			atomic.AddInt32(&n, 1)
		}
	}()
	gosched()

	// Move clock forward to just before the first tick.
	clock.Add(9 * time.Second)
	if atomic.LoadInt32(&n) != 0 {
		t.Fatalf("expected 0, got %d", n)
	}

	// Move clock forward to the start of the first tick.
	clock.Add(1 * time.Second)
	if atomic.LoadInt32(&n) != 1 {
		t.Fatalf("expected 1, got %d", n)
	}

	// Move clock forward over several ticks.
	clock.Add(30 * time.Second)
	if atomic.LoadInt32(&n) != 4 {
		t.Fatalf("expected 4, got %d", n)
	}
}

// ResetElectionTimeoutMs sets the minimum and maximum election timeouts to the
// passed values, and returns the old values.
func ResetElectionTimeoutMs(newMin, newMax int) (int, int) {
	oldMin := atomic.LoadInt32(&minimumElectionTimeoutMs)
	oldMax := atomic.LoadInt32(&maximumElectionTimeoutMs)
	atomic.StoreInt32(&minimumElectionTimeoutMs, int32(newMin))
	atomic.StoreInt32(&maximumElectionTimeoutMs, int32(newMax))
	return int(oldMin), int(oldMax)
}

// checkLimitsForObtainingNewCerts checks to see if name can be issued right
// now according to mitigating factors we keep track of and preferences the
// user has set. If a non-nil error is returned, do not issue a new certificate
// for name.
func checkLimitsForObtainingNewCerts(name string) error {
	// User can set hard limit for number of certs for the process to issue
	if onDemandMaxIssue > 0 && atomic.LoadInt32(OnDemandIssuedCount) >= onDemandMaxIssue {
		return fmt.Errorf("%s: maximum certificates issued (%d)", name, onDemandMaxIssue)
	}

	// Make sure name hasn't failed a challenge recently
	failedIssuanceMu.RLock()
	when, ok := failedIssuance[name]
	failedIssuanceMu.RUnlock()
	if ok {
		return fmt.Errorf("%s: throttled; refusing to issue cert since last attempt on %s failed", name, when.String())
	}

	// Make sure, if we've issued a few certificates already, that we haven't
	// issued any recently
	lastIssueTimeMu.Lock()
	since := time.Since(lastIssueTime)
	lastIssueTimeMu.Unlock()
	if atomic.LoadInt32(OnDemandIssuedCount) >= 10 && since < 10*time.Minute {
		return fmt.Errorf("%s: throttled; last certificate was obtained %v ago", name, since)
	}

	// 👍Good to go
	return nil
}

// ConnectToNSQLookupd adds an nsqlookupd address to the list for this Consumer instance.
//
// If it is the first to be added, it initiates an HTTP request to discover nsqd
// producers for the configured topic.
//
// A goroutine is spawned to handle continual polling.
func (r *Consumer) ConnectToNSQLookupd(addr string) error {
	if atomic.LoadInt32(&r.stopFlag) == 1 {
		return errors.New("consumer stopped")
	}
	if atomic.LoadInt32(&r.runningHandlers) == 0 {
		return errors.New("no handlers")
	}

	if err := validatedLookupAddr(addr); err != nil {
		return err
	}

	atomic.StoreInt32(&r.connectedFlag, 1)

	r.mtx.Lock()
	for _, x := range r.lookupdHTTPAddrs {
		if x == addr {
			r.mtx.Unlock()
			return nil
		}
	}
	r.lookupdHTTPAddrs = append(r.lookupdHTTPAddrs, addr)
	numLookupd := len(r.lookupdHTTPAddrs)
	r.mtx.Unlock()

	// if this is the first one, kick off the go loop
	if numLookupd == 1 {
		r.queryLookupd()
		r.wg.Add(1)
		go r.lookupdLoop()
	}

	return nil
}

func (n *Node) checkSlave() {
	n.RLock()
	if n.Slave == nil {
		n.RUnlock()
		return
	}
	slaves := make([]*DB, len(n.Slave))
	copy(slaves, n.Slave)
	n.RUnlock()

	for i := 0; i < len(slaves); i++ {
		if err := slaves[i].Ping(); err != nil {
			golog.Error("Node", "checkSlave", "Ping", 0, "db.Addr", slaves[i].Addr(), "error", err.Error())
		} else {
			if atomic.LoadInt32(&(slaves[i].state)) == Down {
				golog.Info("Node", "checkSlave", "Slave up", 0, "db.Addr", slaves[i].Addr())
				n.UpSlave(slaves[i].addr)
			}
			slaves[i].SetLastPing()
			if atomic.LoadInt32(&(slaves[i].state)) != ManualDown {
				atomic.StoreInt32(&(slaves[i].state), Up)
			}
			continue
		}

		if int64(n.DownAfterNoAlive) > 0 && time.Now().Unix()-slaves[i].GetLastPing() > int64(n.DownAfterNoAlive/time.Second) {
			golog.Info("Node", "checkSlave", "Slave down", 0,
				"db.Addr", slaves[i].Addr(),
				"slave_down_time", int64(n.DownAfterNoAlive/time.Second))
			//If can't ping slave after DownAfterNoAlive, set slave Down
			n.DownSlave(slaves[i].addr, Down)
		}
	}

}

func (r *RouteFetcher) startEventCycle() {
	go func() {
		useCachedToken := true
		for {
			r.logger.Debug("fetching-token")
			token, err := r.UaaClient.FetchToken(useCachedToken)
			if err != nil {
				metrics.IncrementCounter(TokenFetchErrors)
				r.logger.Error("failed-to-fetch-token", err)
			} else {
				r.logger.Debug("token-fetched-successfully")
				if atomic.LoadInt32(&r.stopEventSource) == 1 {
					return
				}
				err = r.subscribeToEvents(token)
				if err != nil && err.Error() == "unauthorized" {
					useCachedToken = false
				} else {
					useCachedToken = true
				}
				if atomic.LoadInt32(&r.stopEventSource) == 1 {
					return
				}
				time.Sleep(time.Duration(r.SubscriptionRetryIntervalInSeconds) * time.Second)
			}
		}
	}()
}

func (elevator *Elevator) animate() {
	i := 0
	for elevator.getNumScheduledStops() > 0 && i < 100000 {
		fmt.Printf("  Moving %s, current floor %d\n", elevator.Direction, *elevator.CurrentFloor)
		if elevator.Direction == Up {
			if atomic.LoadInt32(elevator.CurrentFloor) < int32(elevator.numFloors-1) {
				atomic.AddInt32(elevator.CurrentFloor, 1)
				time.Sleep(10 * time.Millisecond)
			}
		}
		if elevator.Direction == Down {
			if atomic.LoadInt32(elevator.CurrentFloor) > int32(0) {
				atomic.AddInt32(elevator.CurrentFloor, -1)
				time.Sleep(10 * time.Millisecond)
			}
		}
		if elevator.scheduledStops[*elevator.CurrentFloor] == 1 {
			fmt.Printf("Visiting floor %d\n", *elevator.CurrentFloor)
			elevator.descheduleStop(*elevator.CurrentFloor)
		}
		i = i + 1
	}
	if i >= 100000 {
		panic("Something is really wrong, elevator went cuckoo")
	}

	elevator.stopElevator()
}

// prints message every second until returned thunk is executed.
// useful for determining what function calls are hanging.
func CheckHang(message string, args ...interface{}) func() {
	done := int32(0)
	go func() {

		// do nothing if done is called quickly; reduces printed messages
		time.Sleep(1000 * time.Millisecond)
		if atomic.LoadInt32(&done) != 0 {
			return
		}

		// loop until done, printing message at each interval
		for atomic.LoadInt32(&done) == 0 {
			fmt.Printf(message, args...)
			fmt.Printf("\t There are %v live goroutines.\n", runtime.NumGoroutine())
			time.Sleep(1000 * time.Millisecond)
		}

	}()

	// thunk to be called by client when done
	return func() {
		atomic.StoreInt32(&done, 1)
	}

}

// String implements fmt.Stringer.
func (p *peer) String() string {
	return fmt.Sprintf("Peer %s [%s]", p.id,
		fmt.Sprintf("reputation %3d, ", atomic.LoadInt32(&p.rep))+
			fmt.Sprintf("capacity %3d, ", atomic.LoadInt32(&p.capacity))+
			fmt.Sprintf("ignored %4d", p.ignored.Size()),
	)
}

func (s *S) TestRemoveUnits(c *gocheck.C) {
	var calls int32
	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		v := atomic.LoadInt32(&calls)
		atomic.StoreInt32(&calls, v+1)
		w.WriteHeader(http.StatusNoContent)
	}))
	srvc := service.Service{Name: "mysql", Endpoint: map[string]string{"production": ts.URL}}
	err := srvc.Create()
	c.Assert(err, gocheck.IsNil)
	defer s.conn.Services().Remove(bson.M{"_id": "mysql"})
	app := App{
		Name:      "chemistry",
		Framework: "python",
	}
	instance := service.ServiceInstance{
		Name:        "my-inst",
		ServiceName: "mysql",
		Teams:       []string{s.team.Name},
		Apps:        []string{app.Name},
	}
	instance.Create()
	defer s.conn.ServiceInstances().Remove(bson.M{"name": "my-inst"})
	err = s.conn.Apps().Insert(app)
	c.Assert(err, gocheck.IsNil)
	defer s.conn.Apps().Remove(bson.M{"name": app.Name})
	c.Assert(err, gocheck.IsNil)
	s.provisioner.Provision(&app)
	defer s.provisioner.Destroy(&app)
	app.AddUnits(4)
	otherApp := App{Name: app.Name, Units: app.Units}
	err = otherApp.RemoveUnits(2)
	c.Assert(err, gocheck.IsNil)
	ts.Close()
	units := s.provisioner.GetUnits(&app)
	c.Assert(units, gocheck.HasLen, 3) // when you provision you already have one, so it's 4+1-2 (in provisioner, in app struct we have 2)
	c.Assert(units[0].Name, gocheck.Equals, "chemistry/0")
	c.Assert(units[1].Name, gocheck.Equals, "chemistry/3")
	c.Assert(units[2].Name, gocheck.Equals, "chemistry/4")
	err = app.Get()
	c.Assert(err, gocheck.IsNil)
	c.Assert(app.Framework, gocheck.Equals, "python")
	c.Assert(app.Units, gocheck.HasLen, 2)
	c.Assert(app.Units[0].Name, gocheck.Equals, "chemistry/3")
	c.Assert(app.Units[1].Name, gocheck.Equals, "chemistry/4")
	ok := make(chan int8)
	go func() {
		for _ = range time.Tick(1e3) {
			if atomic.LoadInt32(&calls) == 2 {
				ok <- 1
				return
			}
		}
	}()
	select {
	case <-ok:
	case <-time.After(2e9):
		c.Fatal("Did not call service endpoint twice.")
	}
}

// returns ticks of current and previous seconds
func (t *QpsTracker) Ticks() (c1, e1, c2, e2 int32) {
	c1 = atomic.LoadInt32(&t.c[int((atomic.LoadInt64(&t.active)+int64(1))%2)])
	e1 = atomic.LoadInt32(&t.e[int((atomic.LoadInt64(&t.active)+int64(1))%2)])
	c2 = atomic.LoadInt32(&t.c[int((atomic.LoadInt64(&t.active))%2)])
	e2 = atomic.LoadInt32(&t.e[int((atomic.LoadInt64(&t.active))%2)])
	return
}

func (t *testCourse) Elect(k icarus.LoginSession) (bool, error) {
	conc := atomic.AddInt32(&t.concurrent, 1)
	if conc > 1 && t.noConcurrent {
		log.Fatalf("2 goroutines electing at the same time!")
	}
	defer atomic.AddInt32(&t.concurrent, -1)

	if t.forbidden {
		log.Fatalf("Entered forbidden elect function.")
	}

	log.Printf("Electing...Remaining %d, Elected %d", t.remaining, t.elected)
	if reflect.TypeOf(k).Name() != "string" {
		log.Fatalf("Wrong type of login session.")
	}
	if k.(string) != session {
		log.Fatalf("Wrong value of login session.")
	}

	atomic.AddInt32(&t.elected, 1)
	time.Sleep(time.Duration(rand.Float32()*3000) * time.Millisecond)
	if atomic.LoadInt32(&t.errorToMake) > 0 {
		atomic.AddInt32(&t.errorToMake, -1)
		return false, errors.New("False Alarm")
	} else {
		if atomic.LoadInt32(&t.remaining) > 0 {
			atomic.AddInt32(&t.remaining, -1)
			return false, nil
		} else {
			log.Println("Elected!")
			return true, nil
		}
	}
}

func (m *RWMutexTracker) RLock() {
	m.logOnce.Do(m.startLogger)
	atomic.AddInt32(&m.nwaitr, 1)

	// Catch read-write-read lock. See if somebody (us? via
	// another goroutine?) already has a read lock, and then
	// somebody else is waiting to write, meaning our second read
	// will deadlock.
	if atomic.LoadInt32(&m.nhaver) > 0 && atomic.LoadInt32(&m.nwaitw) > 0 {
		buf := getBuf()
		buf = buf[:runtime.Stack(buf, false)]
		log.Printf("Potential R-W-R deadlock at: %s", buf)
		putBuf(buf)
	}

	m.mu.RLock()
	atomic.AddInt32(&m.nwaitr, -1)
	atomic.AddInt32(&m.nhaver, 1)

	gid := GoroutineID()
	m.hmu.Lock()
	defer m.hmu.Unlock()
	if m.holdr == nil {
		m.holdr = make(map[int64]bool)
	}
	if m.holdr[gid] {
		buf := getBuf()
		buf = buf[:runtime.Stack(buf, false)]
		log.Fatalf("Recursive call to RLock: %s", buf)
	}
	m.holdr[gid] = true
}

func (q *Reader) ConnectToNSQ(addr string) error {
	if atomic.LoadInt32(&q.stopFlag) == 1 {
		return errors.New("reader stopped")
	}

	if atomic.LoadInt32(&q.runningHandlers) == 0 {
		return errors.New("no handlers")
	}

	_, ok := q.nsqConnections[addr]
	if ok {
		return ErrAlreadyConnected
	}

	log.Printf("[%s] connecting to nsqd", addr)

	connection, err := newNSQConn(addr, q.ReadTimeout, q.WriteTimeout)
	if err != nil {
		return err
	}

	err = connection.sendCommand(Subscribe(q.TopicName, q.ChannelName, q.ShortIdentifier, q.LongIdentifier))
	if err != nil {
		connection.Close()
		return fmt.Errorf("[%s] failed to subscribe to %s:%s - %s", q.TopicName, q.ChannelName, err.Error())
	}

	q.nsqConnections[connection.String()] = connection

	go q.readLoop(connection)
	go q.finishLoop(connection)

	return nil
}