Golang zk.WorldACL函數代碼示例

func TestEtcdSequence(t *testing.T) {
	conn, _ := NewEtcdConn(testServer)
	err := DeleteRecursive(conn, "/zk", -1)
	if err != nil {
		t.Error(err)
	}
	defer conn.Close()

	if _, err := conn.Create("/zk", nil, 0, zk.WorldACL(zk.PermAll)); err != nil {
		t.Fatalf("conn.Create: %v", err)
	}

	_, err = conn.Create("/zk/", nil, zk.FlagSequence, zk.WorldACL(zk.PermAll))
	if err != nil {
		t.Errorf("conn.Create: %v", err)
	}

	_, err = conn.Create("/zk/", nil, zk.FlagSequence, zk.WorldACL(zk.PermAll))
	if err != nil {
		t.Errorf("conn.Create: %v", err)
	}

	_, err = conn.Create("/zk/", nil, zk.FlagSequence, zk.WorldACL(zk.PermAll))
	if err != nil {
		t.Errorf("conn.Create: %v", err)
	}

	_, err = conn.Create("/zk/action_", nil, zk.FlagSequence, zk.WorldACL(zk.PermAll))
	if err != nil {
		t.Errorf("conn.Create: %v", err)
	}
}

func DeleteRecursive(zconn Conn, zkPath string, version int) error {
	// version: -1 delete any version of the node at path - only applies to the top node
	err := zconn.Delete(zkPath, int32(version))
	if err == nil {
		return nil
	}
	if !ZkErrorEqual(err, zk.ErrNotEmpty) {
		return err
	}
	// Remove the ability for other nodes to get created while we are trying to delete.
	// Otherwise, you can enter a race condition, or get starved out from deleting.
	_, err = zconn.SetACL(zkPath, zk.WorldACL(zk.PermAdmin|zk.PermDelete|zk.PermRead), int32(version))
	if err != nil {
		return err
	}
	children, _, err := zconn.Children(zkPath)
	if err != nil {
		return err
	}
	for _, child := range children {
		err := DeleteRecursive(zconn, path.Join(zkPath, child), -1)
		if err != nil && !ZkErrorEqual(err, zk.ErrNoNode) {
			return fmt.Errorf("zkutil: recursive delete failed: %v", err)
		}
	}

	err = zconn.Delete(zkPath, int32(version))
	if err != nil && !ZkErrorEqual(err, zk.ErrNotEmpty) {
		err = fmt.Errorf("zkutil: nodes getting recreated underneath delete (app race condition): %v", zkPath)
	}
	return err
}

func TestChildren(t *testing.T) {
	conn := NewConn()
	defer conn.Close()
	nodes := []string{"/zk", "/zk/foo", "/zk/bar"}
	wantChildren := []string{"bar", "foo"}
	for _, path := range nodes {
		if _, err := conn.Create(path, nil, 0, zk.WorldACL(zk.PermAll)); err != nil {
			t.Fatalf("conn.Create: %v", err)
		}
	}
	children, _, err := conn.Children("/zk")
	if err != nil {
		t.Fatalf(`conn.Children("/zk"): %v`, err)
	}
	sort.Strings(children)
	if length := len(children); length != 2 {
		t.Errorf("children: got %v, wanted %v", children, wantChildren)
	}

	for i, path := range children {
		if wantChildren[i] != path {
			t.Errorf("children: got %v, wanted %v", children, wantChildren)
			break
		}
	}

}

func TestSequence(t *testing.T) {
	conn := NewConn()
	defer conn.Close()
	if _, err := conn.Create("/zk", nil, 0, zk.WorldACL(zk.PermAll)); err != nil {
		t.Fatalf("conn.Create: %v", err)
	}

	newPath, err := conn.Create("/zk/", nil, zk.FlagSequence, zk.WorldACL(zk.PermAll))
	if err != nil {
		t.Errorf("conn.Create: %v", err)
	}
	if wanted := "/zk/0000000001"; newPath != wanted {
		t.Errorf("new path: got %q, wanted %q", newPath, wanted)
	}

	newPath, err = conn.Create("/zk/", nil, zk.FlagSequence, zk.WorldACL(zk.PermAll))
	if err != nil {
		t.Errorf("conn.Create: %v", err)
	}

	if wanted := "/zk/0000000002"; newPath != wanted {
		t.Errorf("new path: got %q, wanted %q", newPath, wanted)
	}

	if err := conn.Delete("/zk/0000000002", -1); err != nil {
		t.Fatalf("conn.Delete: %v", err)
	}

	newPath, err = conn.Create("/zk/", nil, zk.FlagSequence, zk.WorldACL(zk.PermAll))
	if err != nil {
		t.Errorf("conn.Create: %v", err)
	}

	if wanted := "/zk/0000000003"; newPath != wanted {
		t.Errorf("new path: got %q, wanted %q", newPath, wanted)
	}

	newPath, err = conn.Create("/zk/action_", nil, zk.FlagSequence, zk.WorldACL(zk.PermAll))
	if err != nil {
		t.Errorf("conn.Create: %v", err)
	}

	if wanted := "/zk/action_0000000004"; newPath != wanted {
		t.Errorf("new path: got %q, wanted %q", newPath, wanted)
	}

}

func (s *testUtilSuite) SetUpSuite(c *C) {
	conn, err := zkhelper.ConnectToZkWithTimeout(*testZKAddr, time.Second)
	c.Assert(err, IsNil)
	s.zkConn = conn

	s.rootPath = "/zk/tso_util_test"

	_, err = zkhelper.CreateRecursive(s.zkConn, s.rootPath, "", 0, zk.WorldACL(zkhelper.PERM_DIRECTORY))
	c.Assert(err, IsNil)
}

func saveTimestamp(conn zkhelper.Conn, rootPath string, ts int64) error {
	var buf [8]byte
	binary.BigEndian.PutUint64(buf[:], uint64(ts))

	tsPath := getTimestampPath(rootPath)

	_, err := conn.Set(tsPath, buf[:], -1)
	if zkhelper.ZkErrorEqual(err, zk.ErrNoNode) {
		_, err = conn.Create(tsPath, buf[:], 0, zk.WorldACL(zkhelper.PERM_FILE))
	}

	return errors.Trace(err)
}

func (s *testUtilSuite) TestLeader(c *C) {
	conn, err := zkhelper.ConnectToZkWithTimeout(*testZKAddr, time.Second)
	c.Assert(err, IsNil)
	defer conn.Close()

	leaderPath := getLeaderPath(s.rootPath)
	conn.Delete(leaderPath, -1)

	_, err = GetLeader(conn, s.rootPath)
	c.Assert(err, NotNil)

	_, _, err = GetWatchLeader(conn, s.rootPath)
	c.Assert(err, NotNil)

	_, err = zkhelper.CreateRecursive(conn, leaderPath, "", 0, zk.WorldACL(zkhelper.PERM_FILE))
	c.Assert(err, IsNil)

	_, err = GetLeader(conn, s.rootPath)
	c.Assert(err, NotNil)

	_, _, err = GetWatchLeader(conn, s.rootPath)
	c.Assert(err, NotNil)

	addr := "127.0.0.1:1234"
	m := map[string]interface{}{
		"Addr": addr,
	}

	data, err := json.Marshal(m)
	c.Assert(err, IsNil)

	_, err = conn.Set(leaderPath, data, -1)
	c.Assert(err, IsNil)

	v, err := GetLeader(conn, s.rootPath)
	c.Assert(err, IsNil)
	c.Assert(v, Equals, addr)

	v, _, err = GetWatchLeader(conn, s.rootPath)
	c.Assert(err, IsNil)
	c.Assert(v, Equals, addr)
}

func main() {
	servers := []string{"127.0.0.1:2181"}
	conf := zk.ConnConf{
		RecvTimeout:    5 * time.Second,
		ConnTimeout:    5 * time.Second,
		SessionTimeout: 1,
	}
	c, _, err := zk.ConnectWithConf(servers, conf)
	if err != nil {
		panic(err)
	} else {
		_, err := c.Create("/gozk-test/1", []byte("test"), 0, zk.WorldACL(zk.PermAll))
		if err != nil {
			panic(err)
		}
		_, _, err = c.Get("/zk/codis")
		if err != nil {
			panic(err)
		}
		c.Close()
	}
}

func TestBasic(t *testing.T) {
	conn := NewConn()
	defer conn.Close()

	// Make sure Conn implements the interface.
	var _ Conn = conn
	if _, err := conn.Create("/zk", nil, 0, zk.WorldACL(zk.PermAll)); err != nil {
		t.Fatalf("conn.Create: %v", err)
	}

	if _, err := conn.Create("/zk/foo", []byte("foo"), 0, zk.WorldACL(zk.PermAll)); err != nil {
		t.Fatalf("conn.Create: %v", err)
	}
	data, _, err := conn.Get("/zk/foo")
	if err != nil {
		t.Fatalf("conn.Get: %v", err)
	}
	if string(data) != "foo" {
		t.Errorf("got %q, wanted %q", data, "foo")
	}

	if _, err := conn.Set("/zk/foo", []byte("bar"), -1); err != nil {
		t.Fatalf("conn.Set: %v", err)
	}

	data, _, err = conn.Get("/zk/foo")
	if err != nil {
		t.Fatalf("conn.Get: %v", err)
	}
	if string(data) != "bar" {
		t.Errorf("got %q, wanted %q", data, "bar")
	}

	// Try Set with the wrong version.
	if _, err := conn.Set("/zk/foo", []byte("bar"), 0); err == nil {
		t.Error("conn.Set with a wrong version: expected error")
	}

	// Try Get with a node that doesn't exist.
	if _, _, err := conn.Get("/zk/rabarbar"); err == nil {
		t.Error("conn.Get with a node that doesn't exist: expected error")
	}

	// Try Set with a node that doesn't exist.
	if _, err := conn.Set("/zk/barbarbar", []byte("bar"), -1); err == nil {
		t.Error("conn.Get with a node that doesn't exist: expected error")
	}

	// Try Create with a node that exists.
	if _, err := conn.Create("/zk/foo", []byte("foo"), 0, zk.WorldACL(zk.PermAll)); err == nil {
		t.Errorf("conn.Create with a node that exists: expected error")
	}
	// Try Create with a node whose parents don't exist.
	if _, err := conn.Create("/a/b/c", []byte("foo"), 0, zk.WorldACL(zk.PermAll)); err == nil {
		t.Errorf("conn.Create with a node whose parents don't exist: expected error")
	}

	if err := conn.Delete("/zk/foo", -1); err != nil {
		t.Errorf("conn.Delete: %v", err)
	}
	_, stat, err := conn.Exists("/zk/foo")
	if err != nil {
		t.Errorf("conn.Exists: %v", err)
	}
	if stat != nil {
		t.Errorf("/zk/foo should be deleted, got: %v", stat)
	}

}

func TestWatches(t *testing.T) {
	conn := NewConn()
	defer conn.Close()

	if _, err := conn.Create("/zk", nil, 0, zk.WorldACL(zk.PermAll)); err != nil {
		t.Fatalf("conn.Create: %v", err)
	}

	if _, err := conn.Create("/zk/foo", []byte("foo"), 0, zk.WorldACL(zk.PermAll)); err != nil {
		t.Fatalf("conn.Create: %v", err)
	}
	_, _, watch, err := conn.ExistsW("/zk/foo")
	if err != nil {
		t.Errorf("conn.ExistsW: %v", err)
	}

	if err := conn.Delete("/zk/foo", -1); err != nil {
		t.Error(err)
	}

	if err := fireWatch(t, watch); err != nil {
		t.Error(err)
	}

	// Creating a child sends an event to ChildrenW.
	_, _, watch, err = conn.ChildrenW("/zk")
	if err != nil {
		t.Errorf(`conn.ChildrenW("/zk"): %v`, err)
	}
	if _, err := conn.Create("/zk/foo", nil, 0, zk.WorldACL(zk.PermAll)); err != nil {
		t.Fatalf("conn.Create: %v", err)
	}

	if err := fireWatch(t, watch); err != nil {
		t.Error(err)
	}
	// Updating sends an event to GetW.

	_, _, watch, err = conn.GetW("/zk")
	if err != nil {
		t.Errorf(`conn.GetW("/zk"): %v`, err)
	}

	if _, err := conn.Set("/zk", []byte("foo"), -1); err != nil {
		t.Errorf("conn.Set /zk: %v", err)
	}

	if err := fireWatch(t, watch); err != nil {
		t.Error(err)
	}

	// Deleting sends an event to ExistsW and to ChildrenW of the
	// parent.
	_, _, watch, err = conn.ExistsW("/zk/foo")
	if err != nil {
		t.Errorf("conn.ExistsW: %v", err)
	}

	_, _, parentWatch, err := conn.ChildrenW("/zk")
	if err != nil {
		t.Errorf(`conn.ChildrenW("/zk"): %v`, err)
	}

	if err := conn.Delete("/zk/foo", -1); err != nil {
		t.Errorf("conn.Delete: %v", err)
	}

	if err := fireWatch(t, watch); err != nil {
		t.Error(err)
	}
	if err := fireWatch(t, parentWatch); err != nil {
		t.Error(err)
	}
}

func DefaultFileACLs() []zk.ACL {
	return zk.WorldACL(PERM_FILE)
}

// RunTask returns nil when the underlyingtask ends or the error it
// generated.
func (ze *ZElector) RunTask(task ElectorTask) error {
	delay := newBackoffDelay(100*time.Millisecond, 1*time.Minute)
	leaderPath := path.Join(ze.path, "leader")
	for {
		_, err := CreateRecursive(ze.zconn, leaderPath, "", 0, zk.WorldACL(PERM_FILE))
		if err == nil || ZkErrorEqual(err, zk.ErrNodeExists) {
			break
		}
		log.Warningf("election leader create failed: %v", err)
		time.Sleep(delay.NextDelay())
	}

	for {
		err := ze.Lock("RunTask")
		if err != nil {
			log.Warningf("election lock failed: %v", err)
			if err == ErrInterrupted {
				return ErrInterrupted
			}
			continue
		}
		// Confirm your win and deliver acceptance speech. This notifies
		// listeners who will have been watching the leader node for
		// changes.
		_, err = ze.zconn.Set(leaderPath, []byte(ze.contents), -1)
		if err != nil {
			log.Warningf("election promotion failed: %v", err)
			continue
		}

		log.Infof("election promote leader %v", leaderPath)
		taskErrChan := make(chan error)
		go func() {
			taskErrChan <- task.Run()
		}()

	watchLeader:
		// Watch the leader so we can get notified if something goes wrong.
		data, _, watch, err := ze.zconn.GetW(leaderPath)
		if err != nil {
			log.Warningf("election unable to watch leader node %v %v", leaderPath, err)
			// FIXME(msolo) Add delay
			goto watchLeader
		}

		if string(data) != ze.contents {
			log.Warningf("election unable to promote leader")
			task.Stop()
			// We won the election, but we didn't become the leader. How is that possible?
			// (see Bush v. Gore for some inspiration)
			// It means:
			//   1. Someone isn't playing by the election rules (a bad actor).
			//      Hard to detect - let's assume we don't have this problem. :)
			//   2. We lost our connection somehow and the ephemeral lock was cleared,
			//      allowing someone else to win the election.
			continue
		}

		// This is where we start our target process and watch for its failure.
	waitForEvent:
		select {
		case <-ze.interrupted:
			log.Warning("election interrupted - stop child process")
			task.Stop()
			// Once the process dies from the signal, this will all tear down.
			goto waitForEvent
		case taskErr := <-taskErrChan:
			// If our code fails, unlock to trigger an election.
			log.Infof("election child process ended: %v", taskErr)
			ze.Unlock()
			if task.Interrupted() {
				log.Warningf("election child process interrupted - stepping down")
				return ErrInterrupted
			}
			continue
		case zevent := <-watch:
			// We had a zk connection hiccup.  We have a few choices,
			// but it depends on the constraints and the events.
			//
			// If we get SESSION_EXPIRED our connection loss triggered an
			// election that we won't have won and the thus the lock was
			// automatically freed. We have no choice but to start over.
			if zevent.State == zk.StateExpired {
				log.Warningf("election leader watch expired")
				task.Stop()
				continue
			}

			// Otherwise, we had an intermittent issue or something touched
			// the node. Either we lost our position or someone broke
			// protocol and touched the leader node.  We just reconnect and
			// revalidate. In the meantime, assume we are still the leader
			// until we determine otherwise.
			//
			// On a reconnect we will be able to see the leader
			// information. If we still hold the position, great. If not, we
			// kill the associated process.
			//
//.........這裏部分代碼省略.........

func DefaultDirACLs() []zk.ACL {
	return zk.WorldACL(PERM_DIRECTORY)
}

// LockWithTimeout returns nil when the lock is acquired. A lock is
// held if the file exists and you are the creator. Setting the wait
// to zero makes this a nonblocking lock check.
//
// FIXME(msolo) Disallow non-super users from removing the lock?
func (zm *zMutex) LockWithTimeout(wait time.Duration, desc string) (err error) {
	timer := time.NewTimer(wait)
	defer func() {
		if panicErr := recover(); panicErr != nil || err != nil {
			zm.deleteLock()
		}
	}()
	// Ensure the rendezvous node is here.
	// FIXME(msolo) Assuming locks are contended, it will be cheaper to assume this just
	// exists.
	_, err = CreateRecursive(zm.zconn, zm.path, "", 0, zk.WorldACL(PERM_DIRECTORY))
	if err != nil && !ZkErrorEqual(err, zk.ErrNodeExists) {
		return err
	}

	lockPrefix := path.Join(zm.path, "lock-")
	zflags := zk.FlagSequence
	if zm.ephemeral {
		zflags = zflags | zk.FlagEphemeral
	}

	// update node content
	var lockContent map[string]interface{}
	err = json.Unmarshal([]byte(zm.contents), &lockContent)
	if err != nil {
		return err
	}
	lockContent["desc"] = desc
	newContent, err := json.Marshal(lockContent)
	if err != nil {
		return err
	}

createlock:
	lockCreated, err := zm.zconn.Create(lockPrefix, newContent, int32(zflags), zk.WorldACL(PERM_FILE))
	if err != nil {
		return err
	}
	name := path.Base(lockCreated)
	zm.mu.Lock()
	zm.name = name
	zm.mu.Unlock()

trylock:
	children, _, err := zm.zconn.Children(zm.path)
	if err != nil {
		return fmt.Errorf("zkutil: trylock failed %v", err)
	}
	sort.Strings(children)
	if len(children) == 0 {
		return fmt.Errorf("zkutil: empty lock: %v", zm.path)
	}

	if children[0] == name {
		// We are the lock owner.
		return nil
	}

	// This is the degenerate case of a nonblocking lock check. It's not optimal, but
	// also probably not worth optimizing.
	if wait == 0 {
		return ErrTimeout
	}
	prevLock := ""
	for i := 1; i < len(children); i++ {
		if children[i] == name {
			prevLock = children[i-1]
			break
		}
	}
	if prevLock == "" {
		// This is an interesting case. The node disappeared
		// underneath us, probably due to a session loss. We can
		// recreate the lock node (with a new sequence number) and
		// keep trying.
		log.Warningf("zkutil: no lock node found: %v/%v", zm.path, zm.name)
		goto createlock
	}

	zkPrevLock := path.Join(zm.path, prevLock)
	exist, stat, watch, err := zm.zconn.ExistsW(zkPrevLock)
	if err != nil {
		// FIXME(msolo) Should this be a retry?
		return fmt.Errorf("zkutil: unable to watch previous lock node %v %v", zkPrevLock, err)
	}
	if stat == nil || !exist {
		goto trylock
	}
	select {
	case <-timer.C:
		return ErrTimeout
	case <-zm.interrupted:
		return ErrInterrupted
	case event := <-watch:
		log.Infof("zkutil: lock event: %v", event)
//.........這裏部分代碼省略.........

// Close the release channel when you want to clean up nicely.
func CreatePidNode(zconn Conn, zkPath string, contents string, done chan struct{}) error {
	// On the first try, assume the cluster is up and running, that will
	// help hunt down any config issues present at startup
	if _, err := zconn.Create(zkPath, []byte(contents), zk.FlagEphemeral, zk.WorldACL(PERM_FILE)); err != nil {
		if ZkErrorEqual(err, zk.ErrNodeExists) {
			err = zconn.Delete(zkPath, -1)
		}
		if err != nil {
			return fmt.Errorf("zkutil: failed deleting pid node: %v: %v", zkPath, err)
		}
		_, err = zconn.Create(zkPath, []byte(contents), zk.FlagEphemeral, zk.WorldACL(PERM_FILE))
		if err != nil {
			return fmt.Errorf("zkutil: failed creating pid node: %v: %v", zkPath, err)
		}
	}

	go func() {
		for {
			_, _, watch, err := zconn.GetW(zkPath)
			if err != nil {
				if ZkErrorEqual(err, zk.ErrNoNode) {
					_, err = zconn.Create(zkPath, []byte(contents), zk.FlagEphemeral, zk.WorldACL(zk.PermAll))
					if err != nil {
						log.Warningf("failed recreating pid node: %v: %v", zkPath, err)
					} else {
						log.Infof("recreated pid node: %v", zkPath)
						continue
					}
				} else {
					log.Warningf("failed reading pid node: %v", err)
				}
			} else {
				select {
				case event := <-watch:
					if ZkEventOk(event) && event.Type == zk.EventNodeDeleted {
						// Most likely another process has started up. However,
						// there is a chance that an ephemeral node is deleted by
						// the session expiring, yet that same session gets a watch
						// notification. This seems like buggy behavior, but rather
						// than race too hard on the node, just wait a bit and see
						// if the situation resolves itself.
						log.Warningf("pid deleted: %v", zkPath)
					} else {
						log.Infof("pid node event: %v", event)
					}
					// break here and wait for a bit before attempting
				case <-done:
					log.Infof("pid watcher stopped on done: %v", zkPath)
					return
				}
			}
			select {
			// No one likes a thundering herd, least of all zk.
			case <-time.After(5*time.Second + time.Duration(rand.Int63n(55e9))):
			case <-done:
				log.Infof("pid watcher stopped on done: %v", zkPath)
				return
			}
		}
	}()

	return nil
}