go1.16 (#14783)

vendor/github.com/go-redis/redis/v8/sentinel.go

@@ -36,6 +36,12 @@ type FailoverOptions struct {
 	// Route all commands to slave read-only nodes.
 	SlaveOnly bool
 
+	// Use slaves disconnected with master when cannot get connected slaves
+	// Now, this option only works in RandomSlaveAddr function.
+	UseDisconnectedSlaves bool
+
+	// Client queries sentinels in a random order
+	QuerySentinelRandomly bool
 	// Following options are copied from Options struct.
 
 	Dialer    func(ctx context.Context, network, addr string) (net.Conn, error)
@@ -167,6 +173,10 @@ func NewFailoverClient(failoverOpt *FailoverOptions) *Client {
 	sentinelAddrs := make([]string, len(failoverOpt.SentinelAddrs))
 	copy(sentinelAddrs, failoverOpt.SentinelAddrs)
 
+	rand.Shuffle(len(sentinelAddrs), func(i, j int) {
+		sentinelAddrs[i], sentinelAddrs[j] = sentinelAddrs[j], sentinelAddrs[i]
+	})
+
 	failover := &sentinelFailover{
 		opt:           failoverOpt,
 		sentinelAddrs: sentinelAddrs,
@@ -433,10 +443,22 @@ func (c *sentinelFailover) closeSentinel() error {
 }
 
 func (c *sentinelFailover) RandomSlaveAddr(ctx context.Context) (string, error) {
-	addresses, err := c.slaveAddrs(ctx)
+	if c.opt == nil {
+		return "", errors.New("opt is nil")
+	}
+
+	addresses, err := c.slaveAddrs(ctx, false)
 	if err != nil {
 		return "", err
 	}
+
+	if len(addresses) == 0 && c.opt.UseDisconnectedSlaves {
+		addresses, err = c.slaveAddrs(ctx, true)
+		if err != nil {
+			return "", err
+		}
+	}
+
 	if len(addresses) == 0 {
 		return c.MasterAddr(ctx)
 	}
@@ -488,7 +510,7 @@ func (c *sentinelFailover) MasterAddr(ctx context.Context) (string, error) {
 	return "", errors.New("redis: all sentinels specified in configuration are unreachable")
 }
 
-func (c *sentinelFailover) slaveAddrs(ctx context.Context) ([]string, error) {
+func (c *sentinelFailover) slaveAddrs(ctx context.Context, useDisconnected bool) ([]string, error) {
 	c.mu.RLock()
 	sentinel := c.sentinel
 	c.mu.RUnlock()
@@ -511,6 +533,8 @@ func (c *sentinelFailover) slaveAddrs(ctx context.Context) ([]string, error) {
 		_ = c.closeSentinel()
 	}
 
+	var sentinelReachable bool
+
 	for i, sentinelAddr := range c.sentinelAddrs {
 		sentinel := NewSentinelClient(c.opt.sentinelOptions(sentinelAddr))
 
@@ -521,15 +545,21 @@ func (c *sentinelFailover) slaveAddrs(ctx context.Context) ([]string, error) {
 			_ = sentinel.Close()
 			continue
 		}
-
+		sentinelReachable = true
+		addrs := parseSlaveAddrs(slaves, useDisconnected)
+		if len(addrs) == 0 {
+			continue
+		}
 		// Push working sentinel to the top.
 		c.sentinelAddrs[0], c.sentinelAddrs[i] = c.sentinelAddrs[i], c.sentinelAddrs[0]
 		c.setSentinel(ctx, sentinel)
 
-		addrs := parseSlaveAddrs(slaves)
 		return addrs, nil
 	}
 
+	if sentinelReachable {
+		return []string{}, nil
+	}
 	return []string{}, errors.New("redis: all sentinels specified in configuration are unreachable")
 }
 
@@ -550,12 +580,11 @@ func (c *sentinelFailover) getSlaveAddrs(ctx context.Context, sentinel *Sentinel
 			c.opt.MasterName, err)
 		return []string{}
 	}
-	return parseSlaveAddrs(addrs)
+	return parseSlaveAddrs(addrs, false)
 }
 
-func parseSlaveAddrs(addrs []interface{}) []string {
+func parseSlaveAddrs(addrs []interface{}, keepDisconnected bool) []string {
 	nodes := make([]string, 0, len(addrs))
-
 	for _, node := range addrs {
 		ip := ""
 		port := ""
@@ -577,8 +606,12 @@ func parseSlaveAddrs(addrs []interface{}) []string {
 
 		for _, flag := range flags {
 			switch flag {
-			case "s_down", "o_down", "disconnected":
+			case "s_down", "o_down":
 				isDown = true
+			case "disconnected":
+				if !keepDisconnected {
+					isDown = true
+				}
 			}
 		}
 
@@ -705,7 +738,7 @@ func NewFailoverClusterClient(failoverOpt *FailoverOptions) *ClusterClient {
 			Addr: masterAddr,
 		}}
 
-		slaveAddrs, err := failover.slaveAddrs(ctx)
+		slaveAddrs, err := failover.slaveAddrs(ctx, false)
 		if err != nil {
 			return nil, err
 		}