feature: add support for set keepttl (#1499)

* feature: add support for set keepttl

README.md

@@ -120,6 +120,9 @@ Some corner cases:
 // SET key value EX 10 NX
 set, err := rdb.SetNX(ctx, "key", "value", 10*time.Second).Result()
 
+// SET key value keepttl NX
+set, err := rdb.SetNX(ctx, "key", "value", redis.KeepTTL).Result()
+
 // SORT list LIMIT 0 2 ASC
 vals, err := rdb.Sort(ctx, "list", &redis.Sort{Offset: 0, Count: 2, Order: "ASC"}).Result()
 

commands.go

@@ -9,6 +9,10 @@ import (
 	"github.com/go-redis/redis/v8/internal"
 )
 
+// KeepTTL used when set with keepttl option
+// Example: Set(ctx, key, value, redis.KeepTTL).
+const KeepTTL = -1
+
 func usePrecise(dur time.Duration) bool {
 	return dur < time.Second || dur%time.Second != 0
 }
@@ -756,6 +760,7 @@ func (c cmdable) MSetNX(ctx context.Context, values ...interface{}) *BoolCmd {
 //
 // Use expiration for `SETEX`-like behavior.
 // Zero expiration means the key has no expiration time.
+// KeepTTL(-1) expiration means command set adds keepttl option.
 func (c cmdable) Set(ctx context.Context, key string, value interface{}, expiration time.Duration) *StatusCmd {
 	args := make([]interface{}, 3, 5)
 	args[0] = "set"
@@ -767,7 +772,10 @@ func (c cmdable) Set(ctx context.Context, key string, value interface{}, expirat
 		} else {
 			args = append(args, "ex", formatSec(ctx, expiration))
 		}
+	} else if expiration == KeepTTL {
+		args = append(args, "keepttl")
 	}
+
 	cmd := NewStatusCmd(ctx, args...)
 	_ = c(ctx, cmd)
 	return cmd
@@ -776,18 +784,23 @@ func (c cmdable) Set(ctx context.Context, key string, value interface{}, expirat
 // Redis `SET key value [expiration] NX` command.
 //
 // Zero expiration means the key has no expiration time.
+// KeepTTL(-1) expiration means set command adds keepttl option.
 func (c cmdable) SetNX(ctx context.Context, key string, value interface{}, expiration time.Duration) *BoolCmd {
 	var cmd *BoolCmd
-	if expiration == 0 {
+	switch {
+	case expiration == 0:
 		// Use old `SETNX` to support old Redis versions.
 		cmd = NewBoolCmd(ctx, "setnx", key, value)
-	} else {
+	case expiration == KeepTTL:
+		cmd = NewBoolCmd(ctx, "set", key, value, "keepttl", "nx")
+	default:
 		if usePrecise(expiration) {
 			cmd = NewBoolCmd(ctx, "set", key, value, "px", formatMs(ctx, expiration), "nx")
 		} else {
 			cmd = NewBoolCmd(ctx, "set", key, value, "ex", formatSec(ctx, expiration), "nx")
 		}
 	}
+
 	_ = c(ctx, cmd)
 	return cmd
 }
@@ -795,17 +808,22 @@ func (c cmdable) SetNX(ctx context.Context, key string, value interface{}, expir
 // Redis `SET key value [expiration] XX` command.
 //
 // Zero expiration means the key has no expiration time.
+// KeepTTL(-1) expiration means set command adds keepttl option.
 func (c cmdable) SetXX(ctx context.Context, key string, value interface{}, expiration time.Duration) *BoolCmd {
 	var cmd *BoolCmd
-	if expiration == 0 {
+	switch {
+	case expiration == 0:
 		cmd = NewBoolCmd(ctx, "set", key, value, "xx")
-	} else {
+	case expiration == KeepTTL:
+		cmd = NewBoolCmd(ctx, "set", key, value, "keepttl", "xx")
+	default:
 		if usePrecise(expiration) {
 			cmd = NewBoolCmd(ctx, "set", key, value, "px", formatMs(ctx, expiration), "xx")
 		} else {
 			cmd = NewBoolCmd(ctx, "set", key, value, "ex", formatSec(ctx, expiration), "xx")
 		}
 	}
+
 	_ = c(ctx, cmd)
 	return cmd
 }

commands_test.go

@@ -1145,6 +1145,23 @@ var _ = Describe("Commands", func() {
 			}, "1s", "100ms").Should(Equal(redis.Nil))
 		})
 
+		It("should Set with keepttl", func() {
+			// set with ttl
+			set := client.Set(ctx, "key", "hello", 5 * time.Second)
+			Expect(set.Err()).NotTo(HaveOccurred())
+			Expect(set.Val()).To(Equal("OK"))
+
+			// set with keepttl
+			set = client.Set(ctx, "key", "hello1", redis.KeepTTL)
+			Expect(set.Err()).NotTo(HaveOccurred())
+			Expect(set.Val()).To(Equal("OK"))
+
+			ttl := client.TTL(ctx, "key")
+			Expect(ttl.Err()).NotTo(HaveOccurred())
+			// set keepttl will Retain the ttl associated with the key
+			Expect(ttl.Val().Nanoseconds()).NotTo(Equal(-1))
+		})
+
 		It("should SetGet", func() {
 			set := client.Set(ctx, "key", "hello", 0)
 			Expect(set.Err()).NotTo(HaveOccurred())
@@ -1183,6 +1200,16 @@ var _ = Describe("Commands", func() {
 			Expect(val).To(Equal("hello"))
 		})
 
+		It("should SetNX with keepttl", func() {
+			isSet, err := client.SetNX(ctx, "key", "hello1", redis.KeepTTL).Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(isSet).To(Equal(true))
+
+			ttl := client.TTL(ctx, "key")
+			Expect(ttl.Err()).NotTo(HaveOccurred())
+			Expect(ttl.Val().Nanoseconds()).To(Equal(int64(-1)))
+		})
+
 		It("should SetXX", func() {
 			isSet, err := client.SetXX(ctx, "key", "hello2", 0).Result()
 			Expect(err).NotTo(HaveOccurred())
@@ -1217,6 +1244,32 @@ var _ = Describe("Commands", func() {
 			Expect(val).To(Equal("hello2"))
 		})
 
+		It("should SetXX with keepttl", func() {
+			isSet, err := client.SetXX(ctx, "key", "hello2", time.Second).Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(isSet).To(Equal(false))
+
+			err = client.Set(ctx, "key", "hello", time.Second).Err()
+			Expect(err).NotTo(HaveOccurred())
+
+			isSet, err = client.SetXX(ctx, "key", "hello2", 5*time.Second).Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(isSet).To(Equal(true))
+
+			isSet, err = client.SetXX(ctx, "key", "hello3", redis.KeepTTL).Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(isSet).To(Equal(true))
+
+			val, err := client.Get(ctx, "key").Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(val).To(Equal("hello3"))
+
+			// set keepttl will Retain the ttl associated with the key
+			ttl, err := client.TTL(ctx, "key").Result()
+			Expect(err).NotTo(HaveOccurred())
+			Expect(ttl).NotTo(Equal(-1))
+		})
+
 		It("should SetRange", func() {
 			set := client.Set(ctx, "key", "Hello World", 0)
 			Expect(set.Err()).NotTo(HaveOccurred())