fix races shown in comments, lets see if we can omit holding a lock for the whole function

Signed-off-by: Sandor Szücs <[email protected]>

Author: szuecs

ring.go

@@ -241,18 +241,25 @@ func (c *ringShards) SetAddrs(addrs map[string]string) {
 		if addr, ok := addrs[k]; ok && shard.addr == addr {
 			shards[k] = shard
 		} else {
+			// close shards that are not reused
 			defer func() {
-				err := shard.Client.Close()
-				if err != nil {
-					internal.Logger.Printf(context.Background(), "Failed to close ring shard client %s %s: %v", k, shard.addr, err)
+				c.mu.Lock()
+				if !c.closed {
+					err := shard.Client.Close()
+					if err != nil {
+						internal.Logger.Printf(context.Background(), "Failed to close ring shard client %s %s: %v", k, shard.addr, err)
+					}
 				}
+				c.mu.Unlock()
 			}()
 		}
 	}
 
+	newShardNames := make([]string, 0)
 	for k, addr := range addrs {
 		if shard, ok := c.shards[k]; !ok || shard.addr != addr {
 			shards[k] = newRingShard(c.opt, k, addr)
+			newShardNames = append(newShardNames, k)
 		}
 	}
 
@@ -262,13 +269,13 @@ func (c *ringShards) SetAddrs(addrs map[string]string) {
 	}
 
 	c.mu.Lock()
-	if !c.closed {
+	if c.closed {
+		for _, k := range newShardNames {
+			shards[k].Client.Close()
+		}
+	} else {
 		c.shards = shards
 		c.list = list
-	} else {
-		for _, shard := range shards {
-			shard.Client.Close()
-		}
 	}
 	c.mu.Unlock()