Merge pull request redis#978 from go-redis/fix/lua-readonly-error

Retry master node on readonly errors. Fixes redis#977

Author: vmihailenco

cluster.go

@@ -862,7 +862,7 @@ func (c *ClusterClient) Watch(fn func(*Tx) error, keys ...string) error {
 			continue
 		}
 
-		if err == pool.ErrClosed {
+		if err == pool.ErrClosed || internal.IsReadOnlyError(err) {
 			node, err = c.slotMasterNode(slot)
 			if err != nil {
 				return err
@@ -960,7 +960,7 @@ func (c *ClusterClient) defaultProcess(cmd Cmder) error {
 			continue
 		}
 
-		if err == pool.ErrClosed {
+		if err == pool.ErrClosed || internal.IsReadOnlyError(err) {
 			node = nil
 			continue
 		}

internal/error.go

@@ -47,7 +47,8 @@ func IsBadConn(err error, allowTimeout bool) bool {
 		return false
 	}
 	if IsRedisError(err) {
-		return strings.HasPrefix(err.Error(), "READONLY ")
+		// #790
+		return IsReadOnlyError(err)
 	}
 	if allowTimeout {
 		if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
@@ -82,3 +83,7 @@ func IsMovedError(err error) (moved bool, ask bool, addr string) {
 func IsLoadingError(err error) bool {
 	return strings.HasPrefix(err.Error(), "LOADING ")
 }
+
+func IsReadOnlyError(err error) bool {
+	return strings.HasPrefix(err.Error(), "READONLY ")
+}