Add NewFailoverClusterClient

cluster.go

@@ -49,7 +49,7 @@ type ClusterOptions struct {
 	// and load-balance read/write operations between master and slaves.
 	// It can use service like ZooKeeper to maintain configuration information
 	// and Cluster.ReloadState to manually trigger state reloading.
-	ClusterSlots func() ([]ClusterSlot, error)
+	ClusterSlots func(context.Context) ([]ClusterSlot, error)
 
 	// Following options are copied from Options struct.
 
@@ -987,7 +987,7 @@ func (c *ClusterClient) PoolStats() *PoolStats {
 
 func (c *ClusterClient) loadState(ctx context.Context) (*clusterState, error) {
 	if c.opt.ClusterSlots != nil {
-		slots, err := c.opt.ClusterSlots()
+		slots, err := c.opt.ClusterSlots(ctx)
 		if err != nil {
 			return nil, err
 		}

cluster_test.go

@@ -911,7 +911,7 @@ var _ = Describe("ClusterClient", func() {
 			failover = true
 
 			opt = redisClusterOptions()
-			opt.ClusterSlots = func() ([]redis.ClusterSlot, error) {
+			opt.ClusterSlots = func(ctx context.Context) ([]redis.ClusterSlot, error) {
 				slots := []redis.ClusterSlot{{
 					Start: 0,
 					End:   4999,
@@ -965,7 +965,7 @@ var _ = Describe("ClusterClient", func() {
 
 			opt = redisClusterOptions()
 			opt.RouteRandomly = true
-			opt.ClusterSlots = func() ([]redis.ClusterSlot, error) {
+			opt.ClusterSlots = func(ctx context.Context) ([]redis.ClusterSlot, error) {
 				slots := []redis.ClusterSlot{{
 					Start: 0,
 					End:   4999,

example_test.go

@@ -80,7 +80,7 @@ func ExampleNewClusterClient_manualSetup() {
 	// clusterSlots returns cluster slots information.
 	// It can use service like ZooKeeper to maintain configuration information
 	// and Cluster.ReloadState to manually trigger state reloading.
-	clusterSlots := func() ([]redis.ClusterSlot, error) {
+	clusterSlots := func(ctx context.Context) ([]redis.ClusterSlot, error) {
 		slots := []redis.ClusterSlot{
 			// First node with 1 master and 1 slave.
 			{

go.sum

@@ -40,6 +40,7 @@ github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+W
 github.com/onsi/ginkgo v1.12.1/go.mod h1:zj2OWP4+oCPe1qIXoGWkgMRwljMUYCdkwsT2108oapk=
 github.com/onsi/ginkgo v1.14.0 h1:2mOpI4JVVPBN+WQRa0WKH2eXR+Ey+uK4n7Zj0aYpIQA=
 github.com/onsi/ginkgo v1.14.0/go.mod h1:iSB4RoI2tjJc9BBv4NKIKWKya62Rps+oPG/Lv9klQyY=
+github.com/onsi/ginkgo v1.14.1 h1:jMU0WaQrP0a/YAEq8eJmJKjBoMs+pClEr1vDMlM/Do4=
 github.com/onsi/ginkgo v1.14.1/go.mod h1:iSB4RoI2tjJc9BBv4NKIKWKya62Rps+oPG/Lv9klQyY=
 github.com/onsi/gomega v1.7.1/go.mod h1:XdKZgCCFLUoM/7CFJVPcG8C1xQ1AJ0vpAezJrB7JYyY=
 github.com/onsi/gomega v1.10.1 h1:o0+MgICZLuZ7xjH7Vx6zS/zcu93/BEp1VwkIW1mEXCE=

sentinel.go

@@ -88,6 +88,33 @@ func (opt *FailoverOptions) options() *Options {
 	}
 }
 
+func (opt *FailoverOptions) clusterOptions() *ClusterOptions {
+	return &ClusterOptions{
+		Dialer:    opt.Dialer,
+		OnConnect: opt.OnConnect,
+
+		Username: opt.Username,
+		Password: opt.Password,
+
+		MaxRetries:      opt.MaxRetries,
+		MinRetryBackoff: opt.MinRetryBackoff,
+		MaxRetryBackoff: opt.MaxRetryBackoff,
+
+		DialTimeout:  opt.DialTimeout,
+		ReadTimeout:  opt.ReadTimeout,
+		WriteTimeout: opt.WriteTimeout,
+
+		PoolSize:           opt.PoolSize,
+		PoolTimeout:        opt.PoolTimeout,
+		IdleTimeout:        opt.IdleTimeout,
+		IdleCheckFrequency: opt.IdleCheckFrequency,
+		MinIdleConns:       opt.MinIdleConns,
+		MaxConnAge:         opt.MaxConnAge,
+
+		TLSConfig: opt.TLSConfig,
+	}
+}
+
 // NewFailoverClient returns a Redis client that uses Redis Sentinel
 // for automatic failover. It's safe for concurrent use by multiple
 // goroutines.
@@ -103,8 +130,18 @@ func NewFailoverClient(failoverOpt *FailoverOptions) *Client {
 		opt: opt,
 	}
 
+	// TODO: this overwrites original dialer
+	opt.Dialer = failover.dial
+
+	connPool := newConnPool(opt)
+	failover.onFailover = func(ctx context.Context, addr string) {
+		_ = connPool.Filter(func(cn *pool.Conn) bool {
+			return cn.RemoteAddr().String() != addr
+		})
+	}
+
 	c := Client{
-		baseClient: newBaseClient(opt, failover.Pool()),
+		baseClient: newBaseClient(opt, connPool),
 		ctx:        context.Background(),
 	}
 	c.cmdable = c.Process
@@ -283,14 +320,14 @@ func (c *SentinelClient) Remove(ctx context.Context, name string) *StringCmd {
 	return cmd
 }
 
+//------------------------------------------------------------------------------
+
 type sentinelFailover struct {
 	sentinelAddrs    []string
 	sentinelPassword string
 
 	opt        *Options
-
+	onFailover func(ctx context.Context, addr string)
-	pool     *pool.ConnPool
-	poolOnce sync.Once
 
 	mu          sync.RWMutex
 	masterName  string
@@ -321,15 +358,6 @@ func (c *sentinelFailover) closeSentinel() error {
 	return firstErr
 }
 
-func (c *sentinelFailover) Pool() *pool.ConnPool {
-	c.poolOnce.Do(func() {
-		opt := *c.opt
-		opt.Dialer = c.dial
-		c.pool = newConnPool(&opt)
-	})
-	return c.pool
-}
-
 func (c *sentinelFailover) dial(ctx context.Context, network, _ string) (net.Conn, error) {
 	var addr string
 	var err error
@@ -338,6 +366,9 @@ func (c *sentinelFailover) dial(ctx context.Context, network, _ string) (net.Con
 		addr, err = c.RandomSlaveAddr(ctx)
 	} else {
 		addr, err = c.MasterAddr(ctx)
+		if err == nil {
+			c.trySwitchMaster(ctx, addr)
+		}
 	}
 
 	if err != nil {
@@ -349,15 +380,6 @@ func (c *sentinelFailover) dial(ctx context.Context, network, _ string) (net.Con
 	return net.DialTimeout("tcp", addr, c.opt.DialTimeout)
 }
 
-func (c *sentinelFailover) MasterAddr(ctx context.Context) (string, error) {
-	addr, err := c.masterAddr(ctx)
-	if err != nil {
-		return "", err
-	}
-	c.switchMaster(ctx, addr)
-	return addr, nil
-}
-
 func (c *sentinelFailover) RandomSlaveAddr(ctx context.Context) (string, error) {
 	addresses, err := c.slaveAddresses(ctx)
 	if err != nil {
@@ -369,7 +391,7 @@ func (c *sentinelFailover) RandomSlaveAddr(ctx context.Context) (string, error)
 	return addresses[rand.Intn(len(addresses))], nil
 }
 
-func (c *sentinelFailover) masterAddr(ctx context.Context) (string, error) {
+func (c *sentinelFailover) MasterAddr(ctx context.Context) (string, error) {
 	c.mu.RLock()
 	sentinel := c.sentinel
 	c.mu.RUnlock()
@@ -553,27 +575,26 @@ func parseSlaveAddresses(addrs []interface{}) []string {
 	return nodes
 }
 
-func (c *sentinelFailover) switchMaster(ctx context.Context, addr string) {
+func (c *sentinelFailover) trySwitchMaster(ctx context.Context, addr string) {
 	c.mu.RLock()
-	masterAddr := c._masterAddr
+	currentAddr := c._masterAddr
 	c.mu.RUnlock()
-	if masterAddr == addr {
+
+	if addr == currentAddr {
 		return
 	}
 
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
-	if c._masterAddr == addr {
+	if addr == c._masterAddr {
 		return
 	}
+	c._masterAddr = addr
 
 	internal.Logger.Printf(ctx, "sentinel: new master=%q addr=%q",
 		c.masterName, addr)
-	_ = c.Pool().Filter(func(cn *pool.Conn) bool {
+	go c.onFailover(ctx, addr)
-		return cn.RemoteAddr().String() != addr
-	})
-	c._masterAddr = addr
 }
 
 func (c *sentinelFailover) setSentinel(ctx context.Context, sentinel *SentinelClient) {
@@ -624,7 +645,7 @@ func (c *sentinelFailover) listen(pubsub *PubSub) {
 				continue
 			}
 			addr := net.JoinHostPort(parts[3], parts[4])
-			c.switchMaster(pubsub.getContext(), addr)
+			c.trySwitchMaster(pubsub.getContext(), addr)
 		}
 	}
 }
@@ -637,3 +658,54 @@ func contains(slice []string, str string) bool {
 	}
 	return false
 }
+
+//------------------------------------------------------------------------------
+
+func NewFailoverClusterClient(failoverOpt *FailoverOptions) *ClusterClient {
+	failover := &sentinelFailover{
+		masterName:    failoverOpt.MasterName,
+		sentinelAddrs: failoverOpt.SentinelAddrs,
+
+		opt: failoverOpt.options(),
+	}
+
+	opt := failoverOpt.clusterOptions()
+
+	opt.ClusterSlots = func(ctx context.Context) ([]ClusterSlot, error) {
+		masterAddr, err := failover.MasterAddr(ctx)
+		if err != nil {
+			return nil, err
+		}
+
+		nodes := []ClusterNode{{
+			Addr: masterAddr,
+		}}
+
+		slaveAddrs, err := failover.slaveAddresses(ctx)
+		if err != nil {
+			return nil, err
+		}
+
+		for _, slaveAddr := range slaveAddrs {
+			nodes = append(nodes, ClusterNode{
+				Addr: slaveAddr,
+			})
+		}
+
+		slots := []ClusterSlot{
+			{
+				Start: 0,
+				End:   16383,
+				Nodes: nodes,
+			},
+		}
+		return slots, nil
+	}
+
+	c := NewClusterClient(opt)
+	failover.onFailover = func(ctx context.Context, addr string) {
+		_ = c.ReloadState(ctx)
+	}
+
+	return c
+}

sentinel_test.go

@@ -46,13 +46,13 @@ var _ = Describe("Sentinel", func() {
 		// Wait until slaves are picked up by sentinel.
 		Eventually(func() string {
 			return sentinel1.Info(ctx).Val()
-		}, "10s", "100ms").Should(ContainSubstring("slaves=2"))
+		}, "15s", "100ms").Should(ContainSubstring("slaves=2"))
 		Eventually(func() string {
 			return sentinel2.Info(ctx).Val()
-		}, "10s", "100ms").Should(ContainSubstring("slaves=2"))
+		}, "15s", "100ms").Should(ContainSubstring("slaves=2"))
 		Eventually(func() string {
 			return sentinel3.Info(ctx).Val()
-		}, "10s", "100ms").Should(ContainSubstring("slaves=2"))
+		}, "15s", "100ms").Should(ContainSubstring("slaves=2"))
 
 		// Kill master.
 		sentinelMaster.Shutdown(ctx)
@@ -63,7 +63,7 @@ var _ = Describe("Sentinel", func() {
 		// Wait for Redis sentinel to elect new master.
 		Eventually(func() string {
 			return sentinelSlave1.Info(ctx).Val() + sentinelSlave2.Info(ctx).Val()
-		}, "30s", "100ms").Should(ContainSubstring("role:master"))
+		}, "15s", "100ms").Should(ContainSubstring("role:master"))
 
 		// Check that client picked up new master.
 		Eventually(func() error {
@@ -75,7 +75,7 @@ var _ = Describe("Sentinel", func() {
 		Eventually(func() <-chan *redis.Message {
 			_ = client.Publish(ctx, "foo", "hello").Err()
 			return ch
-		}, "15s").Should(Receive(&msg))
+		}, "15s", "100ms").Should(Receive(&msg))
 		Expect(msg.Channel).To(Equal("foo"))
 		Expect(msg.Payload).To(Equal("hello"))
 	})
@@ -92,3 +92,77 @@ var _ = Describe("Sentinel", func() {
 		Expect(err).NotTo(HaveOccurred())
 	})
 })
+
+var _ = Describe("NewFailoverClusterClient", func() {
+	var client *redis.ClusterClient
+
+	BeforeEach(func() {
+		client = redis.NewFailoverClusterClient(&redis.FailoverOptions{
+			MasterName:    sentinelName,
+			SentinelAddrs: sentinelAddrs,
+		})
+		Expect(client.FlushDB(ctx).Err()).NotTo(HaveOccurred())
+	})
+
+	AfterEach(func() {
+		Expect(client.Close()).NotTo(HaveOccurred())
+	})
+
+	It("should facilitate failover", func() {
+		// Set value on master.
+		err := client.Set(ctx, "foo", "master", 0).Err()
+		Expect(err).NotTo(HaveOccurred())
+
+		// Verify.
+		val, err := sentinelMaster.Get(ctx, "foo").Result()
+		Expect(err).NotTo(HaveOccurred())
+		Expect(val).To(Equal("master"))
+
+		// Create subscription.
+		ch := client.Subscribe(ctx, "foo").Channel()
+
+		// Wait until replicated.
+		Eventually(func() string {
+			return sentinelSlave1.Get(ctx, "foo").Val()
+		}, "15s", "100ms").Should(Equal("master"))
+		Eventually(func() string {
+			return sentinelSlave2.Get(ctx, "foo").Val()
+		}, "15s", "100ms").Should(Equal("master"))
+
+		// Wait until slaves are picked up by sentinel.
+		Eventually(func() string {
+			return sentinel1.Info(ctx).Val()
+		}, "15s", "100ms").Should(ContainSubstring("slaves=2"))
+		Eventually(func() string {
+			return sentinel2.Info(ctx).Val()
+		}, "15s", "100ms").Should(ContainSubstring("slaves=2"))
+		Eventually(func() string {
+			return sentinel3.Info(ctx).Val()
+		}, "15s", "100ms").Should(ContainSubstring("slaves=2"))
+
+		// Kill master.
+		sentinelMaster.Shutdown(ctx)
+		Eventually(func() error {
+			return sentinelMaster.Ping(ctx).Err()
+		}, "15s", "100ms").Should(HaveOccurred())
+
+		// Wait for Redis sentinel to elect new master.
+		Eventually(func() string {
+			return sentinelSlave1.Info(ctx).Val() + sentinelSlave2.Info(ctx).Val()
+		}, "15s", "100ms").Should(ContainSubstring("role:master"))
+
+		// Check that client picked up new master.
+		Eventually(func() error {
+			return client.Get(ctx, "foo").Err()
+		}, "15s", "100ms").ShouldNot(HaveOccurred())
+
+		// Check if subscription is renewed.
+		var msg *redis.Message
+		Eventually(func() <-chan *redis.Message {
+			_ = client.Publish(ctx, "foo", "hello").Err()
+			return ch
+		}, "15s", "100ms").Should(Receive(&msg))
+		Expect(msg.Channel).To(Equal("foo"))
+		Expect(msg.Payload).To(Equal("hello"))
+	})
+})