Merge branch 'v4' of github.com:go-redis/redis into v4

cluster.go

@@ -316,6 +316,92 @@ func (c *ClusterClient) reaper(frequency time.Duration) {
 	}
 }
 
+func (c *ClusterClient) Pipeline() *Pipeline {
+	pipe := &Pipeline{
+		exec: c.pipelineExec,
+	}
+	pipe.commandable.process = pipe.process
+	return pipe
+}
+
+func (c *ClusterClient) Pipelined(fn func(*Pipeline) error) ([]Cmder, error) {
+	return c.Pipeline().pipelined(fn)
+}
+
+func (c *ClusterClient) pipelineExec(cmds []Cmder) error {
+	var retErr error
+
+	cmdsMap := make(map[string][]Cmder)
+	for _, cmd := range cmds {
+		slot := hashtag.Slot(cmd.clusterKey())
+		addr := c.slotMasterAddr(slot)
+		cmdsMap[addr] = append(cmdsMap[addr], cmd)
+	}
+
+	for attempt := 0; attempt <= c.opt.getMaxRedirects(); attempt++ {
+		failedCmds := make(map[string][]Cmder)
+
+		for addr, cmds := range cmdsMap {
+			client, err := c.getClient(addr)
+			if err != nil {
+				setCmdsErr(cmds, err)
+				retErr = err
+				continue
+			}
+
+			cn, err := client.conn()
+			if err != nil {
+				setCmdsErr(cmds, err)
+				retErr = err
+				continue
+			}
+
+			failedCmds, err = c.execClusterCmds(cn, cmds, failedCmds)
+			if err != nil {
+				retErr = err
+			}
+			client.putConn(cn, err, false)
+		}
+
+		cmdsMap = failedCmds
+	}
+
+	return retErr
+}
+
+func (c *ClusterClient) execClusterCmds(
+	cn *pool.Conn, cmds []Cmder, failedCmds map[string][]Cmder,
+) (map[string][]Cmder, error) {
+	if err := writeCmd(cn, cmds...); err != nil {
+		setCmdsErr(cmds, err)
+		return failedCmds, err
+	}
+
+	var firstCmdErr error
+	for i, cmd := range cmds {
+		err := cmd.readReply(cn)
+		if err == nil {
+			continue
+		}
+		if isNetworkError(err) {
+			cmd.reset()
+			failedCmds[""] = append(failedCmds[""], cmds[i:]...)
+			break
+		} else if moved, ask, addr := isMovedError(err); moved {
+			c.lazyReloadSlots()
+			cmd.reset()
+			failedCmds[addr] = append(failedCmds[addr], cmd)
+		} else if ask {
+			cmd.reset()
+			failedCmds[addr] = append(failedCmds[addr], NewCmd("ASKING"), cmd)
+		} else if firstCmdErr == nil {
+			firstCmdErr = err
+		}
+	}
+
+	return failedCmds, firstCmdErr
+}
+
 //------------------------------------------------------------------------------
 
 // ClusterOptions are used to configure a cluster client and should be