Merge pull request #946 from allenwq/clusternode-race

Fix race condition when creating the cluster node

cluster.go

@@ -17,7 +17,6 @@ import (
 	"github.com/go-redis/redis/internal/hashtag"
 	"github.com/go-redis/redis/internal/pool"
 	"github.com/go-redis/redis/internal/proto"
-	"github.com/go-redis/redis/internal/singleflight"
 )
 
 var errClusterNoNodes = fmt.Errorf("redis: cluster has no nodes")
@@ -243,8 +242,6 @@ type clusterNodes struct {
 	clusterAddrs []string
 	closed       bool
 
-	nodeCreateGroup singleflight.Group
-
 	_generation uint32 // atomic
 }
 
@@ -347,11 +344,6 @@ func (c *clusterNodes) GetOrCreate(addr string) (*clusterNode, error) {
 		return node, nil
 	}
 
-	v, err := c.nodeCreateGroup.Do(addr, func() (interface{}, error) {
-		node := newClusterNode(c.opt, addr)
-		return node, nil
-	})
-
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
@@ -361,15 +353,13 @@ func (c *clusterNodes) GetOrCreate(addr string) (*clusterNode, error) {
 
 	node, ok := c.allNodes[addr]
 	if ok {
-		_ = v.(*clusterNode).Close()
 		return node, err
 	}
-	node = v.(*clusterNode)
+
+	node = newClusterNode(c.opt, addr)
 
 	c.allAddrs = appendIfNotExists(c.allAddrs, addr)
-	if err == nil {
-		c.clusterAddrs = append(c.clusterAddrs, addr)
-	}
+	c.clusterAddrs = append(c.clusterAddrs, addr)
 	c.allNodes[addr] = node
 
 	return node, err

internal/singleflight/singleflight.go

@@ -1,64 +0,0 @@
-/*
-Copyright 2013 Google Inc.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-     http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-// Package singleflight provides a duplicate function call suppression
-// mechanism.
-package singleflight
-
-import "sync"
-
-// call is an in-flight or completed Do call
-type call struct {
-	wg  sync.WaitGroup
-	val interface{}
-	err error
-}
-
-// Group represents a class of work and forms a namespace in which
-// units of work can be executed with duplicate suppression.
-type Group struct {
-	mu sync.Mutex       // protects m
-	m  map[string]*call // lazily initialized
-}
-
-// Do executes and returns the results of the given function, making
-// sure that only one execution is in-flight for a given key at a
-// time. If a duplicate comes in, the duplicate caller waits for the
-// original to complete and receives the same results.
-func (g *Group) Do(key string, fn func() (interface{}, error)) (interface{}, error) {
-	g.mu.Lock()
-	if g.m == nil {
-		g.m = make(map[string]*call)
-	}
-	if c, ok := g.m[key]; ok {
-		g.mu.Unlock()
-		c.wg.Wait()
-		return c.val, c.err
-	}
-	c := new(call)
-	c.wg.Add(1)
-	g.m[key] = c
-	g.mu.Unlock()
-
-	c.val, c.err = fn()
-	c.wg.Done()
-
-	g.mu.Lock()
-	delete(g.m, key)
-	g.mu.Unlock()
-
-	return c.val, c.err
-}