Golang context.WithTimeout函数代码示例

func (h *keysHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if !allowMethod(w, r.Method, "HEAD", "GET", "PUT", "POST", "DELETE") {
		return
	}
	w.Header().Set("X-Etcd-Cluster-ID", h.clusterInfo.ID().String())

	ctx, cancel := context.WithTimeout(context.Background(), h.timeout)
	defer cancel()

	rr, err := parseKeyRequest(r, clockwork.NewRealClock())
	if err != nil {
		writeError(w, err)
		return
	}

	resp, err := h.server.Do(ctx, rr)
	if err != nil {
		err = trimErrorPrefix(err, etcdserver.StoreKeysPrefix)
		writeError(w, err)
		return
	}
	switch {
	case resp.Event != nil:
		if err := writeKeyEvent(w, resp.Event, h.timer); err != nil {
			// Should never be reached
			log.Printf("error writing event: %v", err)
		}
	case resp.Watcher != nil:
		ctx, cancel := context.WithTimeout(context.Background(), defaultWatchTimeout)
		defer cancel()
		handleKeyWatch(ctx, w, resp.Watcher, rr.Stream, h.timer)
	default:
		writeError(w, errors.New("received response with no Event/Watcher!"))
	}
}

// init phase:
// - read the shard info, make sure it has sources
func (sdw *SplitDiffWorker) init(ctx context.Context) error {
	sdw.SetState(WorkerStateInit)

	var err error
	shortCtx, cancel := context.WithTimeout(ctx, *remoteActionsTimeout)
	sdw.keyspaceInfo, err = sdw.wr.TopoServer().GetKeyspace(shortCtx, sdw.keyspace)
	cancel()
	if err != nil {
		return fmt.Errorf("cannot read keyspace %v: %v", sdw.keyspace, err)
	}
	shortCtx, cancel = context.WithTimeout(ctx, *remoteActionsTimeout)
	sdw.shardInfo, err = sdw.wr.TopoServer().GetShard(shortCtx, sdw.keyspace, sdw.shard)
	cancel()
	if err != nil {
		return fmt.Errorf("cannot read shard %v/%v: %v", sdw.keyspace, sdw.shard, err)
	}

	if len(sdw.shardInfo.SourceShards) == 0 {
		return fmt.Errorf("shard %v/%v has no source shard", sdw.keyspace, sdw.shard)
	}
	if !sdw.shardInfo.HasMaster() {
		return fmt.Errorf("shard %v/%v has no master", sdw.keyspace, sdw.shard)
	}

	return nil
}

func ExampleKV_getSortedPrefix() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	for i := range make([]int, 3) {
		ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
		_, err = cli.Put(ctx, fmt.Sprintf("key_%d", i), "value")
		cancel()
		if err != nil {
			log.Fatal(err)
		}
	}

	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	resp, err := cli.Get(ctx, "key", clientv3.WithPrefix(), clientv3.WithSort(clientv3.SortByKey, clientv3.SortDescend))
	cancel()
	if err != nil {
		log.Fatal(err)
	}
	for _, ev := range resp.Kvs {
		fmt.Printf("%s : %s\n", ev.Key, ev.Value)
	}
	// Output:
	// key_2 : value
	// key_1 : value
	// key_0 : value
}

func actionUserPasswd(c *cli.Context) {
	api, user := mustUserAPIAndName(c)
	ctx, cancel := context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
	currentUser, err := api.GetUser(ctx, user)
	cancel()
	if currentUser == nil {
		fmt.Fprintln(os.Stderr, err.Error())
		os.Exit(1)
	}
	pass, err := speakeasy.Ask("New password: ")
	if err != nil {
		fmt.Fprintln(os.Stderr, "Error reading password:", err)
		os.Exit(1)
	}

	ctx, cancel = context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
	_, err = api.ChangePassword(ctx, user, pass)
	cancel()
	if err != nil {
		fmt.Fprintln(os.Stderr, err.Error())
		os.Exit(1)
	}

	fmt.Printf("Password updated\n")
}

func TestLockRelease(t *testing.T) {
	SetUp(t)
	defer TearDown(t)

	node1 := lock.New(api, key, "node1")
	ctx1, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
	defer cancel()

	node2 := lock.New(api, key, "node2")
	ctx2, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
	defer cancel()

	if err := node1.Acquire(ctx1); err != nil {
		t.Fatal(err)
	}

	wg := &sync.WaitGroup{}
	wg.Add(1)
	go func() {
		defer wg.Done()
		if err := node2.Acquire(ctx2); err != nil {
			t.Error(err)
		}
	}()
	time.Sleep(200 * time.Millisecond)
	if err := node1.Release(context.Background()); err != nil {
		t.Error(err)
	}
	wg.Wait()
}

// invokeWithRetry calls stub using an exponential backoff retry mechanism
// based on the values provided in retrySettings.
func invokeWithRetry(ctx context.Context, stub APICall, callSettings CallSettings) error {
	retrySettings := callSettings.RetrySettings
	backoffSettings := callSettings.RetrySettings.BackoffSettings
	delay := backoffSettings.DelayTimeoutSettings.Initial
	timeout := backoffSettings.RPCTimeoutSettings.Initial
	for {
		// If the deadline is exceeded...
		if ctx.Err() != nil {
			return ctx.Err()
		}
		timeoutCtx, _ := context.WithTimeout(ctx, backoffSettings.RPCTimeoutSettings.Max)
		timeoutCtx, _ = context.WithTimeout(timeoutCtx, timeout)
		err := stub(timeoutCtx)
		code := grpc.Code(err)
		if code == codes.OK {
			return nil
		}
		if !retrySettings.RetryCodes[code] {
			return err
		}
		delayCtx, _ := context.WithTimeout(ctx, backoffSettings.DelayTimeoutSettings.Max)
		delayCtx, _ = context.WithTimeout(delayCtx, delay)
		<-delayCtx.Done()

		delay = scaleDuration(delay, backoffSettings.DelayTimeoutSettings.Multiplier)
		timeout = scaleDuration(timeout, backoffSettings.RPCTimeoutSettings.Multiplier)
	}
}

func testTimeoutOnDeadServer(t *testing.T, e env) {
	s, cc := setUp(t, nil, math.MaxUint32, "", e)
	tc := testpb.NewTestServiceClient(cc)
	ctx, _ := context.WithTimeout(context.Background(), time.Second)
	if _, err := cc.WaitForStateChange(ctx, grpc.Idle); err != nil {
		t.Fatalf("cc.WaitForStateChange(_, %s) = _, %v, want _, <nil>", grpc.Idle, err)
	}
	ctx, _ = context.WithTimeout(context.Background(), time.Second)
	if _, err := cc.WaitForStateChange(ctx, grpc.Connecting); err != nil {
		t.Fatalf("cc.WaitForStateChange(_, %s) = _, %v, want _, <nil>", grpc.Connecting, err)
	}
	if state, err := cc.State(); err != nil || state != grpc.Ready {
		t.Fatalf("cc.State() = %s, %v, want %s, <nil>", state, err, grpc.Ready)
	}
	ctx, _ = context.WithTimeout(context.Background(), time.Second)
	if _, err := cc.WaitForStateChange(ctx, grpc.Ready); err != context.DeadlineExceeded {
		t.Fatalf("cc.WaitForStateChange(_, %s) = _, %v, want _, %v", grpc.Ready, err, context.DeadlineExceeded)
	}
	s.Stop()
	// Set -1 as the timeout to make sure if transportMonitor gets error
	// notification in time the failure path of the 1st invoke of
	// ClientConn.wait hits the deadline exceeded error.
	ctx, _ = context.WithTimeout(context.Background(), -1)
	if _, err := tc.EmptyCall(ctx, &testpb.Empty{}); grpc.Code(err) != codes.DeadlineExceeded {
		t.Fatalf("TestService/EmptyCall(%v, _) = _, error %v, want _, error code: %d", ctx, err, codes.DeadlineExceeded)
	}
	ctx, _ = context.WithTimeout(context.Background(), time.Second)
	if _, err := cc.WaitForStateChange(ctx, grpc.Ready); err != nil {
		t.Fatalf("cc.WaitForStateChange(_, %s) = _, %v, want _, <nil>", grpc.Ready, err)
	}
	if state, err := cc.State(); err != nil || (state != grpc.Connecting && state != grpc.TransientFailure) {
		t.Fatalf("cc.State() = %s, %v, want %s or %s, <nil>", state, err, grpc.Connecting, grpc.TransientFailure)
	}
	cc.Close()
}

func (n *Node) handleAddressChange(ctx context.Context, member *membership.Member, reconnectAddr string) error {
	newConn, err := n.ConnectToMember(reconnectAddr, 0)
	if err != nil {
		return errors.Wrapf(err, "could connect to member ID %x at observed address %s", member.RaftID, reconnectAddr)
	}

	healthCtx, cancelHealth := context.WithTimeout(ctx, time.Duration(n.Config.ElectionTick)*n.opts.TickInterval)
	defer cancelHealth()

	if err := newConn.HealthCheck(healthCtx); err != nil {
		return errors.Wrapf(err, "%x failed health check at observed address %s", member.RaftID, reconnectAddr)
	}

	if err := n.cluster.ReplaceMemberConnection(member.RaftID, member, newConn, reconnectAddr, false); err != nil {
		newConn.Conn.Close()
		return errors.Wrap(err, "failed to replace connection to raft member")
	}

	// If we're the leader, write the address change to raft
	updateCtx, cancelUpdate := context.WithTimeout(ctx, time.Duration(n.Config.ElectionTick)*n.opts.TickInterval)
	defer cancelUpdate()
	if err := n.updateMember(updateCtx, reconnectAddr, member.RaftID, member.NodeID); err != nil {
		return errors.Wrap(err, "failed to update member address in raft")
	}

	return nil
}

func TestDropRequestFailedNonFailFast(t *testing.T) {
	// Start a backend.
	beLis, err := net.Listen("tcp", "localhost:0")
	if err != nil {
		t.Fatalf("Failed to listen %v", err)
	}
	beAddr := strings.Split(beLis.Addr().String(), ":")
	bePort, err := strconv.Atoi(beAddr[1])
	backends := startBackends(t, besn, beLis)
	defer stopBackends(backends)

	// Start a load balancer.
	lbLis, err := net.Listen("tcp", "localhost:0")
	if err != nil {
		t.Fatalf("Failed to create the listener for the load balancer %v", err)
	}
	lbCreds := &serverNameCheckCreds{
		sn: lbsn,
	}
	lb := grpc.NewServer(grpc.Creds(lbCreds))
	if err != nil {
		t.Fatalf("Failed to generate the port number %v", err)
	}
	be := &lbpb.Server{
		IpAddress:        []byte(beAddr[0]),
		Port:             int32(bePort),
		LoadBalanceToken: lbToken,
		DropRequest:      true,
	}
	var bes []*lbpb.Server
	bes = append(bes, be)
	sl := &lbpb.ServerList{
		Servers: bes,
	}
	ls := newRemoteBalancer(sl)
	lbpb.RegisterLoadBalancerServer(lb, ls)
	go func() {
		lb.Serve(lbLis)
	}()
	defer func() {
		ls.stop()
		lb.Stop()
	}()
	creds := serverNameCheckCreds{
		expected: besn,
	}
	ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
	cc, err := grpc.DialContext(ctx, besn, grpc.WithBalancer(Balancer(&testNameResolver{
		addr: lbLis.Addr().String(),
	})), grpc.WithBlock(), grpc.WithTransportCredentials(&creds))
	if err != nil {
		t.Fatalf("Failed to dial to the backend %v", err)
	}
	helloC := hwpb.NewGreeterClient(cc)
	ctx, _ = context.WithTimeout(context.Background(), 10*time.Millisecond)
	if _, err := helloC.SayHello(ctx, &hwpb.HelloRequest{Name: "grpc"}, grpc.FailFast(false)); grpc.Code(err) != codes.DeadlineExceeded {
		t.Fatalf("%v.SayHello(_, _) = _, %v, want _, %s", helloC, err, codes.DeadlineExceeded)
	}
	cc.Close()
}

func ExampleKV_compact() {
	cli, err := clientv3.New(clientv3.Config{
		Endpoints:   endpoints,
		DialTimeout: dialTimeout,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer cli.Close()

	ctx, cancel := context.WithTimeout(context.Background(), requestTimeout)
	resp, err := cli.Get(ctx, "foo")
	cancel()
	if err != nil {
		log.Fatal(err)
	}
	compRev := resp.Header.Revision // specify compact revision of your choice

	ctx, cancel = context.WithTimeout(context.Background(), requestTimeout)
	_, err = cli.Compact(ctx, compRev)
	cancel()
	if err != nil {
		log.Fatal(err)
	}
}

func roleGrantRevoke(c *cli.Context, grant bool) {
	path := c.String("path")
	if path == "" {
		fmt.Fprintln(os.Stderr, "No path specified; please use `-path`")
		os.Exit(1)
	}

	read := c.Bool("read")
	write := c.Bool("write")
	rw := c.Bool("readwrite")
	permcount := 0
	for _, v := range []bool{read, write, rw} {
		if v {
			permcount++
		}
	}
	if permcount != 1 {
		fmt.Fprintln(os.Stderr, "Please specify exactly one of -read, -write or -readwrite")
		os.Exit(1)
	}
	var permType client.PermissionType
	switch {
	case read:
		permType = client.ReadPermission
	case write:
		permType = client.WritePermission
	case rw:
		permType = client.ReadWritePermission
	}

	api, role := mustRoleAPIAndName(c)
	ctx, cancel := context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
	currentRole, err := api.GetRole(ctx, role)
	cancel()
	if err != nil {
		fmt.Fprintln(os.Stderr, err.Error())
		os.Exit(1)
	}
	ctx, cancel = context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
	var newRole *client.Role
	if grant {
		newRole, err = api.GrantRoleKV(ctx, role, []string{path}, permType)
	} else {
		newRole, err = api.RevokeRoleKV(ctx, role, []string{path}, permType)
	}
	cancel()
	if err != nil {
		fmt.Fprintln(os.Stderr, err.Error())
		os.Exit(1)
	}
	if reflect.DeepEqual(newRole, currentRole) {
		if grant {
			fmt.Printf("Role unchanged; already granted")
		} else {
			fmt.Printf("Role unchanged; already revoked")
		}
	}

	fmt.Printf("Role %s updated\n", role)
}

func main() {
	func() {
		ctx := context.Background()
		ctx = setContextWithAppStartTS(ctx, time.Now().String())
		ctx = setContextWithIP(ctx, "1.2.3.4")
		ctx = setContextWithUserAgent(ctx, "Linux")
		fmt.Println(ctx)
		fmt.Println(getAppStartTSFromContext(ctx))
		fmt.Println(getIPFromContext(ctx))
		fmt.Println(getUserAgentFromContext(ctx))
		fmt.Println("Done 1:", ctx)
	}()
	/*
	   Done 1: context.Background.WithValue(0, "2015-09-02 22:38:00.640981471 -0700 PDT").WithValue(1, "1.2.3.4").WithValue(2, "Linux")
	*/

	fmt.Println()
	func() {
		timeout := 100 * time.Millisecond
		processingTime := time.Nanosecond
		ctx, cancel := context.WithTimeout(context.Background(), timeout)
		cancel()
		send(ctx, processingTime)
		fmt.Println("Done 2")
	}()
	/*
		send Timeout: context canceled
		Done 2
	*/

	fmt.Println()
	func() {
		timeout := 100 * time.Millisecond
		processingTime := time.Nanosecond
		ctx, cancel := context.WithTimeout(context.Background(), timeout)
		defer cancel()
		send(ctx, processingTime)
		fmt.Println("Done 3")
	}()
	/*
		send Done!
		Done 3
	*/

	fmt.Println()
	func() {
		timeout := 100 * time.Millisecond
		processingTime := time.Minute
		ctx, cancel := context.WithTimeout(context.Background(), timeout)
		defer cancel()
		send(ctx, processingTime)
		fmt.Println("Done 4")
	}()
	/*
		send Timeout: context deadline exceeded
		Done 4
	*/
}

// synchronizeReplication phase:
// 1 - ask the subset slave to stop replication
// 2 - sleep for 5 seconds
// 3 - ask the superset slave to stop replication
// Note this is not 100% correct, but good enough for now
func (worker *SQLDiffWorker) synchronizeReplication(ctx context.Context) error {
	worker.SetState(WorkerStateSyncReplication)

	// stop replication on subset slave
	worker.wr.Logger().Infof("Stopping replication on subset slave %v", worker.subset.alias)
	subsetTablet, err := worker.wr.TopoServer().GetTablet(ctx, worker.subset.alias)
	if err != nil {
		return err
	}
	shortCtx, cancel := context.WithTimeout(ctx, *remoteActionsTimeout)
	err = worker.wr.TabletManagerClient().StopSlave(shortCtx, subsetTablet)
	cancel()
	if err != nil {
		return fmt.Errorf("Cannot stop slave %v: %v", worker.subset.alias, err)
	}
	if err := checkDone(ctx); err != nil {
		return err
	}

	// change the cleaner actions from ChangeSlaveType(rdonly)
	// to StartSlave() + ChangeSlaveType(spare)
	wrangler.RecordStartSlaveAction(worker.cleaner, subsetTablet)
	action, err := wrangler.FindChangeSlaveTypeActionByTarget(worker.cleaner, worker.subset.alias)
	if err != nil {
		return fmt.Errorf("cannot find ChangeSlaveType action for %v: %v", worker.subset.alias, err)
	}
	action.TabletType = topo.TYPE_SPARE

	// sleep for a few seconds
	time.Sleep(5 * time.Second)
	if err := checkDone(ctx); err != nil {
		return err
	}

	// stop replication on superset slave
	worker.wr.Logger().Infof("Stopping replication on superset slave %v", worker.superset.alias)
	supersetTablet, err := worker.wr.TopoServer().GetTablet(ctx, worker.superset.alias)
	if err != nil {
		return err
	}
	shortCtx, cancel = context.WithTimeout(ctx, *remoteActionsTimeout)
	err = worker.wr.TabletManagerClient().StopSlave(shortCtx, supersetTablet)
	cancel()
	if err != nil {
		return fmt.Errorf("Cannot stop slave %v: %v", worker.superset.alias, err)
	}

	// change the cleaner actions from ChangeSlaveType(rdonly)
	// to StartSlave() + ChangeSlaveType(spare)
	wrangler.RecordStartSlaveAction(worker.cleaner, supersetTablet)
	action, err = wrangler.FindChangeSlaveTypeActionByTarget(worker.cleaner, worker.superset.alias)
	if err != nil {
		return fmt.Errorf("cannot find ChangeSlaveType action for %v: %v", worker.superset.alias, err)
	}
	action.TabletType = topo.TYPE_SPARE

	return nil
}

// shardsWithTablesSources returns all the shards that have SourceShards set
// to one value, with an array of Tables.
func shardsWithTablesSources(ctx context.Context, wr *wrangler.Wrangler) ([]map[string]string, error) {
	shortCtx, cancel := context.WithTimeout(ctx, *remoteActionsTimeout)
	keyspaces, err := wr.TopoServer().GetKeyspaces(shortCtx)
	cancel()
	if err != nil {
		return nil, err
	}

	wg := sync.WaitGroup{}
	mu := sync.Mutex{} // protects result
	result := make([]map[string]string, 0, len(keyspaces))
	rec := concurrency.AllErrorRecorder{}
	for _, keyspace := range keyspaces {
		wg.Add(1)
		go func(keyspace string) {
			defer wg.Done()
			shortCtx, cancel := context.WithTimeout(ctx, *remoteActionsTimeout)
			shards, err := wr.TopoServer().GetShardNames(shortCtx, keyspace)
			cancel()
			if err != nil {
				rec.RecordError(err)
				return
			}
			for _, shard := range shards {
				wg.Add(1)
				go func(keyspace, shard string) {
					defer wg.Done()
					shortCtx, cancel := context.WithTimeout(ctx, *remoteActionsTimeout)
					si, err := wr.TopoServer().GetShard(shortCtx, keyspace, shard)
					cancel()
					if err != nil {
						rec.RecordError(err)
						return
					}

					if len(si.SourceShards) == 1 && len(si.SourceShards[0].Tables) > 0 {
						mu.Lock()
						result = append(result, map[string]string{
							"Keyspace": keyspace,
							"Shard":    shard,
						})
						mu.Unlock()
					}
				}(keyspace, shard)
			}
		}(keyspace)
	}
	wg.Wait()

	if rec.HasErrors() {
		return nil, rec.Error()
	}
	if len(result) == 0 {
		return nil, fmt.Errorf("There are no shards with SourceShards")
	}
	return result, nil
}

func TestSecondElection(t *testing.T) {
	defer TearDown(t)
	name1 := "node1"
	value1 := "10.1.1.10"
	noms1 := []*Nomination{}
	events1 := []*LeaderEvent{}

	name2 := "node2"
	value2 := "10.1.1.11"
	noms2 := []*Nomination{}
	events2 := []*LeaderEvent{}

	wg := &sync.WaitGroup{}
	wg.Add(2)

	// run first election immediately; resign at 10s
	go func() {
		defer wg.Done()
		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()
		noms1, events1 = RunElection(t, ctx, name1, value1)
	}()

	// run second election at 5s; resign at 15s
	go func() {
		defer wg.Done()
		time.Sleep(5 * time.Second)
		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()
		noms2, events2 = RunElection(t, ctx, name2, value2)
	}()

	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()
	AssertWait(t, ctx, wg)

	t.Log("checking election 1")
	AssertNoms(t, noms1, []*Nomination{
		{Name: name1, Size: 1, Leaders: map[string]string{}},
	})

	AssertEvents(t, events1, []*LeaderEvent{
		{1, map[string]string{name1: value1}},
		{1, map[string]string{}},
	})

	t.Log("checking election 2")
	AssertNoms(t, noms2, []*Nomination{
		{Name: name2, Size: 1, Leaders: map[string]string{}},
	})

	AssertEvents(t, events2, []*LeaderEvent{
		{1, map[string]string{name1: value1}},
		{1, map[string]string{name2: value2}},
		{1, map[string]string{}},
	})
}