Enable reaper on ClusterClient and add tests.

ring.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"gopkg.in/redis.v4/internal"
@@ -65,7 +66,7 @@ func (opt *RingOptions) clientOptions() *Options {
 
 type ringShard struct {
 	Client *Client
-	down   int
+	down   int32
 }
 
 func (shard *ringShard) String() string {
@@ -80,7 +81,7 @@ func (shard *ringShard) String() string {
 
 func (shard *ringShard) IsDown() bool {
 	const threshold = 3
-	return shard.down >= threshold
+	return atomic.LoadInt32(&shard.down) >= threshold
 }
 
 func (shard *ringShard) IsUp() bool {
@@ -91,7 +92,7 @@ func (shard *ringShard) IsUp() bool {
 func (shard *ringShard) Vote(up bool) bool {
 	if up {
 		changed := shard.IsDown()
-		shard.down = 0
+		atomic.StoreInt32(&shard.down, 0)
 		return changed
 	}
 
@@ -99,7 +100,7 @@ func (shard *ringShard) Vote(up bool) bool {
 		return false
 	}
 
-	shard.down++
+	atomic.AddInt32(&shard.down, 1)
 	return shard.IsDown()
 }
 
@@ -157,6 +158,52 @@ func NewRing(opt *RingOptions) *Ring {
 	return ring
 }
 
+// PoolStats returns accumulated connection pool stats.
+func (c *Ring) PoolStats() *PoolStats {
+	var acc PoolStats
+	for _, shard := range c.shards {
+		s := shard.Client.connPool.Stats()
+		acc.Requests += s.Requests
+		acc.Hits += s.Hits
+		acc.Timeouts += s.Timeouts
+		acc.TotalConns += s.TotalConns
+		acc.FreeConns += s.FreeConns
+	}
+	return &acc
+}
+
+// ForEachShard concurrently calls the fn on each live shard in the ring.
+// It returns the first error if any.
+func (c *Ring) ForEachShard(fn func(client *Client) error) error {
+	var wg sync.WaitGroup
+	errCh := make(chan error, 1)
+	for _, shard := range c.shards {
+		if shard.IsDown() {
+			continue
+		}
+
+		wg.Add(1)
+		go func(shard *ringShard) {
+			defer wg.Done()
+			err := fn(shard.Client)
+			if err != nil {
+				select {
+				case errCh <- err:
+				default:
+				}
+			}
+		}(shard)
+	}
+	wg.Wait()
+
+	select {
+	case err := <-errCh:
+		return err
+	default:
+		return nil
+	}
+}
+
 func (c *Ring) cmdInfo(name string) *CommandInfo {
 	c.cmdsInfoOnce.Do(func() {
 		for _, shard := range c.shards {