feat: support eval_ro and evalsha_ro

Signed-off-by: tison <wander4096@gmail.com>

command.go

@@ -65,7 +65,7 @@ func cmdFirstKeyPos(cmd Cmder, info *CommandInfo) int {
 	}
 
 	switch cmd.Name() {
-	case "eval", "evalsha":
+	case "eval", "evalsha", "eval_ro", "evalsha_ro":
 		if cmd.stringArg(2) != "0" {
 			return 3
 		}

commands.go

@@ -339,6 +339,8 @@ type Cmdable interface {
 
 	Eval(ctx context.Context, script string, keys []string, args ...interface{}) *Cmd
 	EvalSha(ctx context.Context, sha1 string, keys []string, args ...interface{}) *Cmd
+	EvalRO(ctx context.Context, script string, keys []string, args ...interface{}) *Cmd
+	EvalShaRO(ctx context.Context, sha1 string, keys []string, args ...interface{}) *Cmd
 	ScriptExists(ctx context.Context, hashes ...string) *BoolSliceCmd
 	ScriptFlush(ctx context.Context) *StatusCmd
 	ScriptKill(ctx context.Context) *StatusCmd
@@ -3010,24 +3012,25 @@ func (c cmdable) MemoryUsage(ctx context.Context, key string, samples ...int) *I
 //------------------------------------------------------------------------------
 
 func (c cmdable) Eval(ctx context.Context, script string, keys []string, args ...interface{}) *Cmd {
-	cmdArgs := make([]interface{}, 3+len(keys), 3+len(keys)+len(args))
-	cmdArgs[0] = "eval"
-	cmdArgs[1] = script
-	cmdArgs[2] = len(keys)
-	for i, key := range keys {
-		cmdArgs[3+i] = key
+	return c.eval(ctx, "eval", script, keys, args...)
 }
-	cmdArgs = appendArgs(cmdArgs, args)
-	cmd := NewCmd(ctx, cmdArgs...)
-	cmd.SetFirstKeyPos(3)
-	_ = c(ctx, cmd)
-	return cmd
+
+func (c cmdable) EvalRO(ctx context.Context, script string, keys []string, args ...interface{}) *Cmd {
+	return c.eval(ctx, "eval_ro", script, keys, args...)
 }
 
 func (c cmdable) EvalSha(ctx context.Context, sha1 string, keys []string, args ...interface{}) *Cmd {
+	return c.eval(ctx, "evalsha", sha1, keys, args...)
+}
+
+func (c cmdable) EvalShaRO(ctx context.Context, sha1 string, keys []string, args ...interface{}) *Cmd {
+	return c.eval(ctx, "evalsha_ro", sha1, keys, args...)
+}
+
+func (c cmdable) eval(ctx context.Context, name, payload string, keys []string, args ...interface{}) *Cmd {
 	cmdArgs := make([]interface{}, 3+len(keys), 3+len(keys)+len(args))
-	cmdArgs[0] = "evalsha"
-	cmdArgs[1] = sha1
+	cmdArgs[0] = name
+	cmdArgs[1] = payload
 	cmdArgs[2] = len(keys)
 	for i, key := range keys {
 		cmdArgs[3+i] = key

commands_test.go

@@ -5413,6 +5413,29 @@ var _ = Describe("Commands", func() {
 		})
 	})
 
+	Describe("EvalRO", func() {
+		It("returns keys and values", func() {
+			vals, err := client.EvalRO(
+				ctx,
+				"return {KEYS[1],ARGV[1]}",
+				[]string{"key"},
+				"hello",
+			).Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(vals).To(Equal([]interface{}{"key", "hello"}))
+		})
+
+		It("returns all values after an error", func() {
+			vals, err := client.EvalRO(
+				ctx,
+				`return {12, {err="error"}, "abc"}`,
+				nil,
+			).Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(vals).To(Equal([]interface{}{int64(12), proto.RedisError("error"), "abc"}))
+		})
+	})
+
 	Describe("SlowLogGet", func() {
 		It("returns slow query result", func() {
 			const key = "slowlog-log-slower-than"

script.go

@@ -11,6 +11,8 @@ import (
 type Scripter interface {
 	Eval(ctx context.Context, script string, keys []string, args ...interface{}) *Cmd
 	EvalSha(ctx context.Context, sha1 string, keys []string, args ...interface{}) *Cmd
+	EvalRO(ctx context.Context, script string, keys []string, args ...interface{}) *Cmd
+	EvalShaRO(ctx context.Context, sha1 string, keys []string, args ...interface{}) *Cmd
 	ScriptExists(ctx context.Context, hashes ...string) *BoolSliceCmd
 	ScriptLoad(ctx context.Context, script string) *StringCmd
 }
@@ -50,10 +52,18 @@ func (s *Script) Eval(ctx context.Context, c Scripter, keys []string, args ...in
 	return c.Eval(ctx, s.src, keys, args...)
 }
 
+func (s *Script) EvalRO(ctx context.Context, c Scripter, keys []string, args ...interface{}) *Cmd {
+	return c.EvalRO(ctx, s.src, keys, args...)
+}
+
 func (s *Script) EvalSha(ctx context.Context, c Scripter, keys []string, args ...interface{}) *Cmd {
 	return c.EvalSha(ctx, s.hash, keys, args...)
 }
 
+func (s *Script) EvalShaRO(ctx context.Context, c Scripter, keys []string, args ...interface{}) *Cmd {
+	return c.EvalShaRO(ctx, s.hash, keys, args...)
+}
+
 // Run optimistically uses EVALSHA to run the script. If script does not exist
 // it is retried using EVAL.
 func (s *Script) Run(ctx context.Context, c Scripter, keys []string, args ...interface{}) *Cmd {
@@ -63,3 +73,13 @@ func (s *Script) Run(ctx context.Context, c Scripter, keys []string, args ...int
 	}
 	return r
 }
+
+// RunRO optimistically uses EVALSHA_RO to run the script. If script does not exist
+// it is retried using EVAL_RO.
+func (s *Script) RunRO(ctx context.Context, c Scripter, keys []string, args ...interface{}) *Cmd {
+	r := s.EvalShaRO(ctx, c, keys, args...)
+	if err := r.Err(); err != nil && strings.HasPrefix(err.Error(), "NOSCRIPT ") {
+		return s.EvalRO(ctx, c, keys, args...)
+	}
+	return r
+}