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Merge remote-tracking branch 'origin/ndyakov/state-machine-conn' into playground/autopipeline

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This commit is contained in:
Nedyalko Dyakov
2025-11-10 13:49:51 +02:00
parent 6fe786a138 dc319c0f7e
commit 7bf921716d
18 changed files with 2713 additions and 112 deletions
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2
.github/workflows/doctests.yaml vendored
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@@ -16,7 +16,7 @@ jobs:
services:
redis-stack:
image: redislabs/client-libs-test:8.0.2
image: redislabs/client-libs-test:8.4-RC1-pre.2
env:
TLS_ENABLED: no
REDIS_CLUSTER: no

139
command.go
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@@ -709,6 +709,68 @@ func (cmd *IntCmd) readReply(rd *proto.Reader) (err error) {
//------------------------------------------------------------------------------
// DigestCmd is a command that returns a uint64 xxh3 hash digest.
//
// This command is specifically designed for the Redis DIGEST command,
// which returns the xxh3 hash of a key's value as a hex string.
// The hex string is automatically parsed to a uint64 value.
//
// The digest can be used for optimistic locking with SetIFDEQ, SetIFDNE,
// and DelExArgs commands.
//
// For examples of client-side digest generation and usage patterns, see:
// example/digest-optimistic-locking/
//
// Redis 8.4+. See https://redis.io/commands/digest/
type DigestCmd struct {
baseCmd
val uint64
}
var _ Cmder = (*DigestCmd)(nil)
func NewDigestCmd(ctx context.Context, args ...interface{}) *DigestCmd {
return &DigestCmd{
baseCmd: baseCmd{
ctx: ctx,
args: args,
},
}
}
func (cmd *DigestCmd) SetVal(val uint64) {
cmd.val = val
}
func (cmd *DigestCmd) Val() uint64 {
return cmd.val
}
func (cmd *DigestCmd) Result() (uint64, error) {
return cmd.val, cmd.err
}
func (cmd *DigestCmd) String() string {
return cmdString(cmd, cmd.val)
}
func (cmd *DigestCmd) readReply(rd *proto.Reader) (err error) {
// Redis DIGEST command returns a hex string (e.g., "a1b2c3d4e5f67890")
// We parse it as a uint64 xxh3 hash value
var hexStr string
hexStr, err = rd.ReadString()
if err != nil {
return err
}
// Parse hex string to uint64
cmd.val, err = strconv.ParseUint(hexStr, 16, 64)
return err
}
//------------------------------------------------------------------------------
type IntSliceCmd struct {
baseCmd
@@ -3816,6 +3878,83 @@ func (cmd *SlowLogCmd) readReply(rd *proto.Reader) error {
//-----------------------------------------------------------------------
type Latency struct {
Name string
Time time.Time
Latest time.Duration
Max time.Duration
}
type LatencyCmd struct {
baseCmd
val []Latency
}
var _ Cmder = (*LatencyCmd)(nil)
func NewLatencyCmd(ctx context.Context, args ...interface{}) *LatencyCmd {
return &LatencyCmd{
baseCmd: baseCmd{
ctx: ctx,
args: args,
},
}
}
func (cmd *LatencyCmd) SetVal(val []Latency) {
cmd.val = val
}
func (cmd *LatencyCmd) Val() []Latency {
return cmd.val
}
func (cmd *LatencyCmd) Result() ([]Latency, error) {
return cmd.val, cmd.err
}
func (cmd *LatencyCmd) String() string {
return cmdString(cmd, cmd.val)
}
func (cmd *LatencyCmd) readReply(rd *proto.Reader) error {
n, err := rd.ReadArrayLen()
if err != nil {
return err
}
cmd.val = make([]Latency, n)
for i := 0; i < len(cmd.val); i++ {
nn, err := rd.ReadArrayLen()
if err != nil {
return err
}
if nn < 3 {
return fmt.Errorf("redis: got %d elements in latency get, expected at least 3", nn)
}
if cmd.val[i].Name, err = rd.ReadString(); err != nil {
return err
}
createdAt, err := rd.ReadInt()
if err != nil {
return err
}
cmd.val[i].Time = time.Unix(createdAt, 0)
latest, err := rd.ReadInt()
if err != nil {
return err
}
cmd.val[i].Latest = time.Duration(latest) * time.Millisecond
maximum, err := rd.ReadInt()
if err != nil {
return err
}
cmd.val[i].Max = time.Duration(maximum) * time.Millisecond
}
return nil
}
//-----------------------------------------------------------------------
type MapStringInterfaceCmd struct {
baseCmd

118
command_digest_test.go Normal file
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@@ -0,0 +1,118 @@
package redis
import (
"context"
"fmt"
"testing"
"github.com/redis/go-redis/v9/internal/proto"
)
func TestDigestCmd(t *testing.T) {
tests := []struct {
name string
hexStr string
expected uint64
wantErr bool
}{
{
name: "zero value",
hexStr: "0",
expected: 0,
wantErr: false,
},
{
name: "small value",
hexStr: "ff",
expected: 255,
wantErr: false,
},
{
name: "medium value",
hexStr: "1234abcd",
expected: 0x1234abcd,
wantErr: false,
},
{
name: "large value",
hexStr: "ffffffffffffffff",
expected: 0xffffffffffffffff,
wantErr: false,
},
{
name: "uppercase hex",
hexStr: "DEADBEEF",
expected: 0xdeadbeef,
wantErr: false,
},
{
name: "mixed case hex",
hexStr: "DeAdBeEf",
expected: 0xdeadbeef,
wantErr: false,
},
{
name: "typical xxh3 hash",
hexStr: "a1b2c3d4e5f67890",
expected: 0xa1b2c3d4e5f67890,
wantErr: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
// Create a mock reader that returns the hex string in RESP format
// Format: $<length>\r\n<data>\r\n
respData := []byte(fmt.Sprintf("$%d\r\n%s\r\n", len(tt.hexStr), tt.hexStr))
rd := proto.NewReader(newMockConn(respData))
cmd := NewDigestCmd(context.Background(), "digest", "key")
err := cmd.readReply(rd)
if (err != nil) != tt.wantErr {
t.Errorf("DigestCmd.readReply() error = %v, wantErr %v", err, tt.wantErr)
return
}
if !tt.wantErr && cmd.Val() != tt.expected {
t.Errorf("DigestCmd.Val() = %d (0x%x), want %d (0x%x)", cmd.Val(), cmd.Val(), tt.expected, tt.expected)
}
})
}
}
func TestDigestCmdResult(t *testing.T) {
cmd := NewDigestCmd(context.Background(), "digest", "key")
expected := uint64(0xdeadbeefcafebabe)
cmd.SetVal(expected)
val, err := cmd.Result()
if err != nil {
t.Errorf("DigestCmd.Result() error = %v", err)
}
if val != expected {
t.Errorf("DigestCmd.Result() = %d (0x%x), want %d (0x%x)", val, val, expected, expected)
}
}
// mockConn is a simple mock connection for testing
type mockConn struct {
data []byte
pos int
}
func newMockConn(data []byte) *mockConn {
return &mockConn{data: data}
}
func (c *mockConn) Read(p []byte) (n int, err error) {
if c.pos >= len(c.data) {
return 0, nil
}
n = copy(p, c.data[c.pos:])
c.pos += n
return n, nil
}

32
commands.go
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@@ -212,9 +212,13 @@ type Cmdable interface {
ShutdownNoSave(ctx context.Context) *StatusCmd
SlaveOf(ctx context.Context, host, port string) *StatusCmd
SlowLogGet(ctx context.Context, num int64) *SlowLogCmd
SlowLogLen(ctx context.Context) *IntCmd
SlowLogReset(ctx context.Context) *StatusCmd
Time(ctx context.Context) *TimeCmd
DebugObject(ctx context.Context, key string) *StringCmd
MemoryUsage(ctx context.Context, key string, samples ...int) *IntCmd
Latency(ctx context.Context) *LatencyCmd
LatencyReset(ctx context.Context, events ...interface{}) *StatusCmd
ModuleLoadex(ctx context.Context, conf *ModuleLoadexConfig) *StringCmd
@@ -675,6 +679,34 @@ func (c cmdable) SlowLogGet(ctx context.Context, num int64) *SlowLogCmd {
return cmd
}
func (c cmdable) SlowLogLen(ctx context.Context) *IntCmd {
cmd := NewIntCmd(ctx, "slowlog", "len")
_ = c(ctx, cmd)
return cmd
}
func (c cmdable) SlowLogReset(ctx context.Context) *StatusCmd {
cmd := NewStatusCmd(ctx, "slowlog", "reset")
_ = c(ctx, cmd)
return cmd
}
func (c cmdable) Latency(ctx context.Context) *LatencyCmd {
cmd := NewLatencyCmd(ctx, "latency", "latest")
_ = c(ctx, cmd)
return cmd
}
func (c cmdable) LatencyReset(ctx context.Context, events ...interface{}) *StatusCmd {
args := make([]interface{}, 2+len(events))
args[0] = "latency"
args[1] = "reset"
copy(args[2:], events)
cmd := NewStatusCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
func (c cmdable) Sync(_ context.Context) {
panic("not implemented")
}

618
commands_test.go
View File

@@ -1796,6 +1796,200 @@ var _ = Describe("Commands", func() {
Expect(get.Err()).To(Equal(redis.Nil))
})
It("should DelExArgs when value matches", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "lock", "token-123", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Delete only if value matches
deleted := client.DelExArgs(ctx, "lock", redis.DelExArgs{
Mode: "IFEQ",
MatchValue: "token-123",
})
Expect(deleted.Err()).NotTo(HaveOccurred())
Expect(deleted.Val()).To(Equal(int64(1)))
// Verify key was deleted
get := client.Get(ctx, "lock")
Expect(get.Err()).To(Equal(redis.Nil))
})
It("should DelExArgs fail when value does not match", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "lock", "token-123", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Try to delete with wrong value
deleted := client.DelExArgs(ctx, "lock", redis.DelExArgs{
Mode: "IFEQ",
MatchValue: "wrong-token",
})
Expect(deleted.Err()).NotTo(HaveOccurred())
Expect(deleted.Val()).To(Equal(int64(0)))
// Verify key was NOT deleted
val, err := client.Get(ctx, "lock").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("token-123"))
})
It("should DelExArgs on non-existent key", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Try to delete non-existent key
deleted := client.DelExArgs(ctx, "nonexistent", redis.DelExArgs{
Mode: "IFEQ",
MatchValue: "any-value",
})
Expect(deleted.Err()).NotTo(HaveOccurred())
Expect(deleted.Val()).To(Equal(int64(0)))
})
It("should DelExArgs with IFEQ", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "temp-key", "temp-value", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Delete with IFEQ
args := redis.DelExArgs{
Mode: "IFEQ",
MatchValue: "temp-value",
}
deleted := client.DelExArgs(ctx, "temp-key", args)
Expect(deleted.Err()).NotTo(HaveOccurred())
Expect(deleted.Val()).To(Equal(int64(1)))
// Verify key was deleted
get := client.Get(ctx, "temp-key")
Expect(get.Err()).To(Equal(redis.Nil))
})
It("should DelExArgs with IFNE", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "temporary", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Delete only if value is NOT "permanent"
args := redis.DelExArgs{
Mode: "IFNE",
MatchValue: "permanent",
}
deleted := client.DelExArgs(ctx, "key", args)
Expect(deleted.Err()).NotTo(HaveOccurred())
Expect(deleted.Val()).To(Equal(int64(1)))
// Verify key was deleted
get := client.Get(ctx, "key")
Expect(get.Err()).To(Equal(redis.Nil))
})
It("should DelExArgs with IFNE fail when value matches", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "permanent", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Try to delete but value matches (should fail)
args := redis.DelExArgs{
Mode: "IFNE",
MatchValue: "permanent",
}
deleted := client.DelExArgs(ctx, "key", args)
Expect(deleted.Err()).NotTo(HaveOccurred())
Expect(deleted.Val()).To(Equal(int64(0)))
// Verify key was NOT deleted
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("permanent"))
})
It("should Digest", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set a value
err := client.Set(ctx, "my-key", "my-value", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Get digest (returns uint64)
digest := client.Digest(ctx, "my-key")
Expect(digest.Err()).NotTo(HaveOccurred())
Expect(digest.Val()).NotTo(BeZero())
// Digest should be consistent
digest2 := client.Digest(ctx, "my-key")
Expect(digest2.Err()).NotTo(HaveOccurred())
Expect(digest2.Val()).To(Equal(digest.Val()))
})
It("should Digest on non-existent key", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Get digest of non-existent key
digest := client.Digest(ctx, "nonexistent")
Expect(digest.Err()).To(Equal(redis.Nil))
})
It("should use Digest with SetArgs IFDEQ", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "value1", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Get digest
digest := client.Digest(ctx, "key")
Expect(digest.Err()).NotTo(HaveOccurred())
// Update using digest
args := redis.SetArgs{
Mode: "IFDEQ",
MatchDigest: digest.Val(),
}
result := client.SetArgs(ctx, "key", "value2", args)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("OK"))
// Verify value was updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("value2"))
})
It("should use Digest with DelExArgs IFDEQ", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "value", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Get digest
digest := client.Digest(ctx, "key")
Expect(digest.Err()).NotTo(HaveOccurred())
// Delete using digest
args := redis.DelExArgs{
Mode: "IFDEQ",
MatchDigest: digest.Val(),
}
deleted := client.DelExArgs(ctx, "key", args)
Expect(deleted.Err()).NotTo(HaveOccurred())
Expect(deleted.Val()).To(Equal(int64(1)))
// Verify key was deleted
get := client.Get(ctx, "key")
Expect(get.Err()).To(Equal(redis.Nil))
})
It("should Incr", func() {
set := client.Set(ctx, "key", "10", 0)
Expect(set.Err()).NotTo(HaveOccurred())
@@ -2474,6 +2668,320 @@ var _ = Describe("Commands", func() {
Expect(ttl).NotTo(Equal(-1))
})
It("should SetIFEQ when value matches", func() {
if RedisVersion < 8.4 {
Skip("CAS/CAD commands require Redis >= 8.4")
}
// Set initial value
err := client.Set(ctx, "key", "old-value", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Update only if current value is "old-value"
result := client.SetIFEQ(ctx, "key", "new-value", "old-value", 0)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("OK"))
// Verify value was updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("new-value"))
})
It("should SetIFEQ fail when value does not match", func() {
if RedisVersion < 8.4 {
Skip("CAS/CAD commands require Redis >= 8.4")
}
// Set initial value
err := client.Set(ctx, "key", "current-value", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Try to update with wrong match value
result := client.SetIFEQ(ctx, "key", "new-value", "wrong-value", 0)
Expect(result.Err()).To(Equal(redis.Nil))
// Verify value was NOT updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("current-value"))
})
It("should SetIFEQ with expiration", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "token-123", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Update with expiration
result := client.SetIFEQ(ctx, "key", "token-456", "token-123", 500*time.Millisecond)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("OK"))
// Verify value was updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("token-456"))
// Wait for expiration
Eventually(func() error {
return client.Get(ctx, "key").Err()
}, "1s", "100ms").Should(Equal(redis.Nil))
})
It("should SetIFNE when value does not match", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "pending", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Update only if current value is NOT "completed"
result := client.SetIFNE(ctx, "key", "processing", "completed", 0)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("OK"))
// Verify value was updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("processing"))
})
It("should SetIFNE fail when value matches", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "completed", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Try to update but value matches (should fail)
result := client.SetIFNE(ctx, "key", "processing", "completed", 0)
Expect(result.Err()).To(Equal(redis.Nil))
// Verify value was NOT updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("completed"))
})
It("should SetArgs with IFEQ", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "counter", "100", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Update with IFEQ
args := redis.SetArgs{
Mode: "IFEQ",
MatchValue: "100",
TTL: 1 * time.Hour,
}
result := client.SetArgs(ctx, "counter", "200", args)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("OK"))
// Verify value was updated
val, err := client.Get(ctx, "counter").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("200"))
})
It("should SetArgs with IFEQ and GET", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "old", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Update with IFEQ and GET old value
args := redis.SetArgs{
Mode: "IFEQ",
MatchValue: "old",
Get: true,
}
result := client.SetArgs(ctx, "key", "new", args)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("old"))
// Verify value was updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("new"))
})
It("should SetArgs with IFNE", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "status", "pending", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Update with IFNE
args := redis.SetArgs{
Mode: "IFNE",
MatchValue: "completed",
TTL: 30 * time.Minute,
}
result := client.SetArgs(ctx, "status", "processing", args)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("OK"))
// Verify value was updated
val, err := client.Get(ctx, "status").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("processing"))
})
It("should SetIFEQGet return previous value", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "old-value", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Update and get previous value
result := client.SetIFEQGet(ctx, "key", "new-value", "old-value", 0)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("old-value"))
// Verify value was updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("new-value"))
})
It("should SetIFNEGet return previous value", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "pending", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Update and get previous value
result := client.SetIFNEGet(ctx, "key", "processing", "completed", 0)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("pending"))
// Verify value was updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("processing"))
})
It("should SetIFDEQ when digest matches", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "value1", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Get digest
digest := client.Digest(ctx, "key")
Expect(digest.Err()).NotTo(HaveOccurred())
// Update using digest
result := client.SetIFDEQ(ctx, "key", "value2", digest.Val(), 0)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("OK"))
// Verify value was updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("value2"))
})
It("should SetIFDEQ fail when digest does not match", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "value1", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Get digest of a different value to use as wrong digest
err = client.Set(ctx, "temp-key", "different-value", 0).Err()
Expect(err).NotTo(HaveOccurred())
wrongDigest := client.Digest(ctx, "temp-key")
Expect(wrongDigest.Err()).NotTo(HaveOccurred())
// Try to update with wrong digest
result := client.SetIFDEQ(ctx, "key", "value2", wrongDigest.Val(), 0)
Expect(result.Err()).To(Equal(redis.Nil))
// Verify value was NOT updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("value1"))
})
It("should SetIFDEQGet return previous value", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "value1", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Get digest
digest := client.Digest(ctx, "key")
Expect(digest.Err()).NotTo(HaveOccurred())
// Update using digest and get previous value
result := client.SetIFDEQGet(ctx, "key", "value2", digest.Val(), 0)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("value1"))
// Verify value was updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("value2"))
})
It("should SetIFDNE when digest does not match", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "value1", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Get digest of a different value
err = client.Set(ctx, "temp-key", "different-value", 0).Err()
Expect(err).NotTo(HaveOccurred())
differentDigest := client.Digest(ctx, "temp-key")
Expect(differentDigest.Err()).NotTo(HaveOccurred())
// Update with different digest (should succeed because digest doesn't match)
result := client.SetIFDNE(ctx, "key", "value2", differentDigest.Val(), 0)
Expect(result.Err()).NotTo(HaveOccurred())
Expect(result.Val()).To(Equal("OK"))
// Verify value was updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("value2"))
})
It("should SetIFDNE fail when digest matches", func() {
SkipBeforeRedisVersion(8.4, "CAS/CAD commands require Redis >= 8.4")
// Set initial value
err := client.Set(ctx, "key", "value1", 0).Err()
Expect(err).NotTo(HaveOccurred())
// Get digest
digest := client.Digest(ctx, "key")
Expect(digest.Err()).NotTo(HaveOccurred())
// Try to update but digest matches (should fail)
result := client.SetIFDNE(ctx, "key", "value2", digest.Val(), 0)
Expect(result.Err()).To(Equal(redis.Nil))
// Verify value was NOT updated
val, err := client.Get(ctx, "key").Result()
Expect(err).NotTo(HaveOccurred())
Expect(val).To(Equal("value1"))
})
It("should SetRange", func() {
set := client.Set(ctx, "key", "Hello World", 0)
Expect(set.Err()).NotTo(HaveOccurred())
@@ -8294,7 +8802,7 @@ var _ = Describe("Commands", func() {
})
})
Describe("SlowLogGet", func() {
Describe("SlowLog", func() {
It("returns slow query result", func() {
const key = "slowlog-log-slower-than"
@@ -8311,6 +8819,114 @@ var _ = Describe("Commands", func() {
Expect(err).NotTo(HaveOccurred())
Expect(len(result)).NotTo(BeZero())
})
It("returns the number of slow queries", Label("NonRedisEnterprise"), func() {
// Reset slowlog
err := client.SlowLogReset(ctx).Err()
Expect(err).NotTo(HaveOccurred())
const key = "slowlog-log-slower-than"
old := client.ConfigGet(ctx, key).Val()
// first slowlog entry is the config set command itself
client.ConfigSet(ctx, key, "0")
defer client.ConfigSet(ctx, key, old[key])
// Set a key to trigger a slow query, and this is the second slowlog entry
client.Set(ctx, "test", "true", 0)
result, err := client.SlowLogLen(ctx).Result()
Expect(err).NotTo(HaveOccurred())
Expect(result).Should(Equal(int64(2)))
// Reset slowlog
err = client.SlowLogReset(ctx).Err()
Expect(err).NotTo(HaveOccurred())
// Check if slowlog is empty, this is the first slowlog entry after reset
result, err = client.SlowLogLen(ctx).Result()
Expect(err).NotTo(HaveOccurred())
Expect(result).Should(Equal(int64(1)))
})
})
Describe("Latency", Label("NonRedisEnterprise"), func() {
It("returns latencies", func() {
const key = "latency-monitor-threshold"
old := client.ConfigGet(ctx, key).Val()
client.ConfigSet(ctx, key, "1")
defer client.ConfigSet(ctx, key, old[key])
err := client.Do(ctx, "DEBUG", "SLEEP", 0.01).Err()
Expect(err).NotTo(HaveOccurred())
result, err := client.Latency(ctx).Result()
Expect(err).NotTo(HaveOccurred())
Expect(len(result)).NotTo(BeZero())
})
It("reset all latencies", func() {
const key = "latency-monitor-threshold"
result, err := client.Latency(ctx).Result()
// reset all latencies
err = client.LatencyReset(ctx).Err()
Expect(err).NotTo(HaveOccurred())
old := client.ConfigGet(ctx, key).Val()
client.ConfigSet(ctx, key, "1")
defer client.ConfigSet(ctx, key, old[key])
// get latency after reset
result, err = client.Latency(ctx).Result()
Expect(err).NotTo(HaveOccurred())
Expect(len(result)).Should(Equal(0))
// create a new latency
err = client.Do(ctx, "DEBUG", "SLEEP", 0.01).Err()
Expect(err).NotTo(HaveOccurred())
// get latency after create a new latency
result, err = client.Latency(ctx).Result()
Expect(err).NotTo(HaveOccurred())
Expect(len(result)).Should(Equal(1))
// reset all latencies again
err = client.LatencyReset(ctx).Err()
Expect(err).NotTo(HaveOccurred())
// get latency after reset again
result, err = client.Latency(ctx).Result()
Expect(err).NotTo(HaveOccurred())
Expect(len(result)).Should(Equal(0))
})
It("reset latencies by add event name args", func() {
const key = "latency-monitor-threshold"
old := client.ConfigGet(ctx, key).Val()
client.ConfigSet(ctx, key, "1")
defer client.ConfigSet(ctx, key, old[key])
result, err := client.Latency(ctx).Result()
Expect(err).NotTo(HaveOccurred())
Expect(len(result)).Should(Equal(0))
err = client.Do(ctx, "DEBUG", "SLEEP", 0.01).Err()
Expect(err).NotTo(HaveOccurred())
result, err = client.Latency(ctx).Result()
Expect(err).NotTo(HaveOccurred())
Expect(len(result)).Should(Equal(1))
// reset latency by event name
err = client.LatencyReset(ctx, result[0].Name).Err()
Expect(err).NotTo(HaveOccurred())
result, err = client.Latency(ctx).Result()
Expect(err).NotTo(HaveOccurred())
Expect(len(result)).Should(Equal(0))
})
})
})

265
digest_test.go Normal file
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@@ -0,0 +1,265 @@
package redis_test
import (
"context"
"os"
"strconv"
"strings"
"testing"
"github.com/redis/go-redis/v9"
)
func init() {
// Initialize RedisVersion from environment variable for regular Go tests
// (Ginkgo tests initialize this in BeforeSuite)
if version := os.Getenv("REDIS_VERSION"); version != "" {
if v, err := strconv.ParseFloat(strings.Trim(version, "\""), 64); err == nil && v > 0 {
RedisVersion = v
}
}
}
// skipIfRedisBelow84 checks if Redis version is below 8.4 and skips the test if so
func skipIfRedisBelow84(t *testing.T) {
if RedisVersion < 8.4 {
t.Skipf("Skipping test: Redis version %.1f < 8.4 (DIGEST command requires Redis 8.4+)", RedisVersion)
}
}
// TestDigestBasic validates that the Digest command returns a uint64 value
func TestDigestBasic(t *testing.T) {
skipIfRedisBelow84(t)
ctx := context.Background()
client := redis.NewClient(&redis.Options{
Addr: "localhost:6379",
})
defer client.Close()
if err := client.Ping(ctx).Err(); err != nil {
t.Skipf("Redis not available: %v", err)
}
client.Del(ctx, "digest-test-key")
// Set a value
err := client.Set(ctx, "digest-test-key", "testvalue", 0).Err()
if err != nil {
t.Fatalf("Failed to set value: %v", err)
}
// Get digest
digestCmd := client.Digest(ctx, "digest-test-key")
if err := digestCmd.Err(); err != nil {
t.Fatalf("Failed to get digest: %v", err)
}
digest := digestCmd.Val()
if digest == 0 {
t.Error("Digest should not be zero for non-empty value")
}
t.Logf("Digest for 'testvalue': %d (0x%016x)", digest, digest)
// Verify same value produces same digest
digest2 := client.Digest(ctx, "digest-test-key").Val()
if digest != digest2 {
t.Errorf("Same value should produce same digest: %d != %d", digest, digest2)
}
client.Del(ctx, "digest-test-key")
}
// TestSetIFDEQWithDigest validates the SetIFDEQ command works with digests
func TestSetIFDEQWithDigest(t *testing.T) {
skipIfRedisBelow84(t)
ctx := context.Background()
client := redis.NewClient(&redis.Options{
Addr: "localhost:6379",
})
defer client.Close()
if err := client.Ping(ctx).Err(); err != nil {
t.Skipf("Redis not available: %v", err)
}
client.Del(ctx, "cas-test-key")
// Set initial value
initialValue := "initial-value"
err := client.Set(ctx, "cas-test-key", initialValue, 0).Err()
if err != nil {
t.Fatalf("Failed to set initial value: %v", err)
}
// Get current digest
correctDigest := client.Digest(ctx, "cas-test-key").Val()
wrongDigest := uint64(12345) // arbitrary wrong digest
// Test 1: SetIFDEQ with correct digest should succeed
result := client.SetIFDEQ(ctx, "cas-test-key", "new-value", correctDigest, 0)
if err := result.Err(); err != nil {
t.Errorf("SetIFDEQ with correct digest failed: %v", err)
} else {
t.Logf("✓ SetIFDEQ with correct digest succeeded")
}
// Verify value was updated
val, err := client.Get(ctx, "cas-test-key").Result()
if err != nil {
t.Fatalf("Failed to get value: %v", err)
}
if val != "new-value" {
t.Errorf("Value not updated: got %q, want %q", val, "new-value")
}
// Test 2: SetIFDEQ with wrong digest should fail
result = client.SetIFDEQ(ctx, "cas-test-key", "another-value", wrongDigest, 0)
if result.Err() != redis.Nil {
t.Errorf("SetIFDEQ with wrong digest should return redis.Nil, got: %v", result.Err())
} else {
t.Logf("✓ SetIFDEQ with wrong digest correctly failed")
}
// Verify value was NOT updated
val, err = client.Get(ctx, "cas-test-key").Result()
if err != nil {
t.Fatalf("Failed to get value: %v", err)
}
if val != "new-value" {
t.Errorf("Value should not have changed: got %q, want %q", val, "new-value")
}
client.Del(ctx, "cas-test-key")
}
// TestSetIFDNEWithDigest validates the SetIFDNE command works with digests
func TestSetIFDNEWithDigest(t *testing.T) {
skipIfRedisBelow84(t)
ctx := context.Background()
client := redis.NewClient(&redis.Options{
Addr: "localhost:6379",
})
defer client.Close()
if err := client.Ping(ctx).Err(); err != nil {
t.Skipf("Redis not available: %v", err)
}
client.Del(ctx, "cad-test-key")
// Set initial value
initialValue := "initial-value"
err := client.Set(ctx, "cad-test-key", initialValue, 0).Err()
if err != nil {
t.Fatalf("Failed to set initial value: %v", err)
}
// Use an arbitrary different digest
wrongDigest := uint64(99999) // arbitrary different digest
// Test 1: SetIFDNE with different digest should succeed
result := client.SetIFDNE(ctx, "cad-test-key", "new-value", wrongDigest, 0)
if err := result.Err(); err != nil {
t.Errorf("SetIFDNE with different digest failed: %v", err)
} else {
t.Logf("✓ SetIFDNE with different digest succeeded")
}
// Verify value was updated
val, err := client.Get(ctx, "cad-test-key").Result()
if err != nil {
t.Fatalf("Failed to get value: %v", err)
}
if val != "new-value" {
t.Errorf("Value not updated: got %q, want %q", val, "new-value")
}
// Test 2: SetIFDNE with matching digest should fail
newDigest := client.Digest(ctx, "cad-test-key").Val()
result = client.SetIFDNE(ctx, "cad-test-key", "another-value", newDigest, 0)
if result.Err() != redis.Nil {
t.Errorf("SetIFDNE with matching digest should return redis.Nil, got: %v", result.Err())
} else {
t.Logf("✓ SetIFDNE with matching digest correctly failed")
}
// Verify value was NOT updated
val, err = client.Get(ctx, "cad-test-key").Result()
if err != nil {
t.Fatalf("Failed to get value: %v", err)
}
if val != "new-value" {
t.Errorf("Value should not have changed: got %q, want %q", val, "new-value")
}
client.Del(ctx, "cad-test-key")
}
// TestDelExArgsWithDigest validates DelExArgs works with digest matching
func TestDelExArgsWithDigest(t *testing.T) {
skipIfRedisBelow84(t)
ctx := context.Background()
client := redis.NewClient(&redis.Options{
Addr: "localhost:6379",
})
defer client.Close()
if err := client.Ping(ctx).Err(); err != nil {
t.Skipf("Redis not available: %v", err)
}
client.Del(ctx, "del-test-key")
// Set a value
value := "delete-me"
err := client.Set(ctx, "del-test-key", value, 0).Err()
if err != nil {
t.Fatalf("Failed to set value: %v", err)
}
// Get correct digest
correctDigest := client.Digest(ctx, "del-test-key").Val()
wrongDigest := uint64(54321)
// Test 1: Delete with wrong digest should fail
deleted := client.DelExArgs(ctx, "del-test-key", redis.DelExArgs{
Mode: "IFDEQ",
MatchDigest: wrongDigest,
}).Val()
if deleted != 0 {
t.Errorf("Delete with wrong digest should not delete: got %d deletions", deleted)
} else {
t.Logf("✓ DelExArgs with wrong digest correctly refused to delete")
}
// Verify key still exists
exists := client.Exists(ctx, "del-test-key").Val()
if exists != 1 {
t.Errorf("Key should still exist after failed delete")
}
// Test 2: Delete with correct digest should succeed
deleted = client.DelExArgs(ctx, "del-test-key", redis.DelExArgs{
Mode: "IFDEQ",
MatchDigest: correctDigest,
}).Val()
if deleted != 1 {
t.Errorf("Delete with correct digest should delete: got %d deletions", deleted)
} else {
t.Logf("✓ DelExArgs with correct digest successfully deleted")
}
// Verify key was deleted
exists = client.Exists(ctx, "del-test-key").Val()
if exists != 0 {
t.Errorf("Key should not exist after successful delete")
}
}

200
example/digest-optimistic-locking/README.md Normal file
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@@ -0,0 +1,200 @@
# Redis Digest & Optimistic Locking Example
This example demonstrates how to use Redis DIGEST command and digest-based optimistic locking with go-redis.
## What is Redis DIGEST?
The DIGEST command (Redis 8.4+) returns a 64-bit xxh3 hash of a key's value. This hash can be used for:
- **Optimistic locking**: Update values only if they haven't changed
- **Change detection**: Detect if a value was modified
- **Conditional operations**: Delete or update based on expected content
## Features Demonstrated
1. **Basic Digest Usage**: Get digest from Redis and verify with client-side calculation
2. **Optimistic Locking with SetIFDEQ**: Update only if digest matches (value unchanged)
3. **Change Detection with SetIFDNE**: Update only if digest differs (value changed)
4. **Conditional Delete**: Delete only if digest matches expected value
5. **Client-Side Digest Generation**: Calculate digests without fetching from Redis
## Requirements
- Redis 8.4+ (for DIGEST command support)
- Go 1.18+
## Installation
```bash
cd example/digest-optimistic-locking
go mod tidy
```
## Running the Example
```bash
# Make sure Redis 8.4+ is running on localhost:6379
redis-server
# In another terminal, run the example
go run .
```
## Expected Output
```
=== Redis Digest & Optimistic Locking Example ===
1. Basic Digest Usage
---------------------
Key: user:1000:name
Value: Alice
Digest: 7234567890123456789 (0x6478a1b2c3d4e5f6)
Client-calculated digest: 7234567890123456789 (0x6478a1b2c3d4e5f6)
✓ Digests match!
2. Optimistic Locking with SetIFDEQ
------------------------------------
Initial value: 100
Current digest: 0x1234567890abcdef
✓ Update successful! New value: 150
✓ Correctly rejected update with wrong digest
3. Detecting Changes with SetIFDNE
-----------------------------------
Initial value: v1.0.0
Old digest: 0xabcdef1234567890
✓ Value changed! Updated to: v2.0.0
✓ Correctly rejected: current value matches the digest
4. Conditional Delete with DelExArgs
-------------------------------------
Created session: session:abc123
Expected digest: 0x9876543210fedcba
✓ Correctly refused to delete (wrong digest)
✓ Successfully deleted with correct digest
✓ Session deleted
5. Client-Side Digest Generation
---------------------------------
Current price: $29.99
Expected digest (calculated client-side): 0xfedcba0987654321
✓ Price updated successfully to $24.99
Binary data example:
Binary data digest: 0x1122334455667788
✓ Binary digest matches!
=== All examples completed successfully! ===
```
## How It Works
### Digest Calculation
Redis uses the **xxh3** hashing algorithm. To calculate digests client-side, use `github.com/zeebo/xxh3`:
```go
import "github.com/zeebo/xxh3"
// For strings
digest := xxh3.HashString("myvalue")
// For binary data
digest := xxh3.Hash([]byte{0x01, 0x02, 0x03})
```
### Optimistic Locking Pattern
```go
// 1. Read current value and get its digest
currentValue := rdb.Get(ctx, "key").Val()
currentDigest := rdb.Digest(ctx, "key").Val()
// 2. Perform business logic
newValue := processValue(currentValue)
// 3. Update only if value hasn't changed
result := rdb.SetIFDEQ(ctx, "key", newValue, currentDigest, 0)
if result.Err() == redis.Nil {
// Value was modified by another client - retry or handle conflict
}
```
### Client-Side Digest (No Extra Round Trip)
```go
// If you know the expected current value, calculate digest client-side
expectedValue := "100"
expectedDigest := xxh3.HashString(expectedValue)
// Update without fetching digest from Redis first
result := rdb.SetIFDEQ(ctx, "counter", "150", expectedDigest, 0)
```
## Use Cases
### 1. Distributed Counter with Conflict Detection
```go
// Multiple clients can safely update a counter
currentValue := rdb.Get(ctx, "counter").Val()
currentDigest := rdb.Digest(ctx, "counter").Val()
newValue := incrementCounter(currentValue)
// Only succeeds if no other client modified it
if rdb.SetIFDEQ(ctx, "counter", newValue, currentDigest, 0).Err() == redis.Nil {
// Retry with new value
}
```
### 2. Session Management
```go
// Delete session only if it contains expected data
sessionData := "user:1234:active"
expectedDigest := xxh3.HashString(sessionData)
deleted := rdb.DelExArgs(ctx, "session:xyz", redis.DelExArgs{
Mode: "IFDEQ",
MatchDigest: expectedDigest,
}).Val()
```
### 3. Configuration Updates
```go
// Update config only if it changed
oldConfig := loadOldConfig()
oldDigest := xxh3.HashString(oldConfig)
newConfig := loadNewConfig()
// Only update if config actually changed
result := rdb.SetIFDNE(ctx, "config", newConfig, oldDigest, 0)
if result.Err() != redis.Nil {
fmt.Println("Config updated!")
}
```
## Advantages Over WATCH/MULTI/EXEC
- **Simpler**: Single command instead of transaction
- **Faster**: No transaction overhead
- **Client-side digest**: Can calculate expected digest without fetching from Redis
- **Works with any command**: Not limited to transactions
## Learn More
- [Redis DIGEST command](https://redis.io/commands/digest/)
- [Redis SET command with IFDEQ/IFDNE](https://redis.io/commands/set/)
- [xxh3 hashing algorithm](https://github.com/Cyan4973/xxHash)
- [github.com/zeebo/xxh3](https://github.com/zeebo/xxh3)
## Comparison: XXH3 vs XXH64
**Note**: Redis uses **XXH3**, not XXH64. If you have `github.com/cespare/xxhash/v2` in your project, it implements XXH64 which produces **different hash values**. You must use `github.com/zeebo/xxh3` for Redis DIGEST operations.
See [XXHASH_LIBRARY_COMPARISON.md](../../XXHASH_LIBRARY_COMPARISON.md) for detailed comparison.

16
example/digest-optimistic-locking/go.mod Normal file
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@@ -0,0 +1,16 @@
module github.com/redis/go-redis/example/digest-optimistic-locking
go 1.18
replace github.com/redis/go-redis/v9 => ../..
require (
github.com/redis/go-redis/v9 v9.16.0
github.com/zeebo/xxh3 v1.0.2
)
require (
github.com/cespare/xxhash/v2 v2.3.0 // indirect
github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
github.com/klauspost/cpuid/v2 v2.0.9 // indirect
)

11
example/digest-optimistic-locking/go.sum Normal file
View File

@@ -0,0 +1,11 @@
github.com/bsm/ginkgo/v2 v2.12.0 h1:Ny8MWAHyOepLGlLKYmXG4IEkioBysk6GpaRTLC8zwWs=
github.com/bsm/gomega v1.27.10 h1:yeMWxP2pV2fG3FgAODIY8EiRE3dy0aeFYt4l7wh6yKA=
github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
github.com/klauspost/cpuid/v2 v2.0.9 h1:lgaqFMSdTdQYdZ04uHyN2d/eKdOMyi2YLSvlQIBFYa4=
github.com/klauspost/cpuid/v2 v2.0.9/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=
github.com/zeebo/assert v1.3.0 h1:g7C04CbJuIDKNPFHmsk4hwZDO5O+kntRxzaUoNXj+IQ=
github.com/zeebo/xxh3 v1.0.2 h1:xZmwmqxHZA8AI603jOQ0tMqmBr9lPeFwGg6d+xy9DC0=
github.com/zeebo/xxh3 v1.0.2/go.mod h1:5NWz9Sef7zIDm2JHfFlcQvNekmcEl9ekUZQQKCYaDcA=

245
example/digest-optimistic-locking/main.go Normal file
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@@ -0,0 +1,245 @@
package main
import (
"context"
"fmt"
"time"
"github.com/redis/go-redis/v9"
"github.com/zeebo/xxh3"
)
func main() {
ctx := context.Background()
// Connect to Redis
rdb := redis.NewClient(&redis.Options{
Addr: "localhost:6379",
})
defer rdb.Close()
// Ping to verify connection
if err := rdb.Ping(ctx).Err(); err != nil {
fmt.Printf("Failed to connect to Redis: %v\n", err)
return
}
fmt.Println("=== Redis Digest & Optimistic Locking Example ===")
fmt.Println()
// Example 1: Basic Digest Usage
fmt.Println("1. Basic Digest Usage")
fmt.Println("---------------------")
basicDigestExample(ctx, rdb)
fmt.Println()
// Example 2: Optimistic Locking with SetIFDEQ
fmt.Println("2. Optimistic Locking with SetIFDEQ")
fmt.Println("------------------------------------")
optimisticLockingExample(ctx, rdb)
fmt.Println()
// Example 3: Detecting Changes with SetIFDNE
fmt.Println("3. Detecting Changes with SetIFDNE")
fmt.Println("-----------------------------------")
detectChangesExample(ctx, rdb)
fmt.Println()
// Example 4: Conditional Delete with DelExArgs
fmt.Println("4. Conditional Delete with DelExArgs")
fmt.Println("-------------------------------------")
conditionalDeleteExample(ctx, rdb)
fmt.Println()
// Example 5: Client-Side Digest Generation
fmt.Println("5. Client-Side Digest Generation")
fmt.Println("---------------------------------")
clientSideDigestExample(ctx, rdb)
fmt.Println()
fmt.Println("=== All examples completed successfully! ===")
}
// basicDigestExample demonstrates getting a digest from Redis
func basicDigestExample(ctx context.Context, rdb *redis.Client) {
// Set a value
key := "user:1000:name"
value := "Alice"
rdb.Set(ctx, key, value, 0)
// Get the digest
digest := rdb.Digest(ctx, key).Val()
fmt.Printf("Key: %s\n", key)
fmt.Printf("Value: %s\n", value)
fmt.Printf("Digest: %d (0x%016x)\n", digest, digest)
// Verify with client-side calculation
clientDigest := xxh3.HashString(value)
fmt.Printf("Client-calculated digest: %d (0x%016x)\n", clientDigest, clientDigest)
if digest == clientDigest {
fmt.Println("✓ Digests match!")
}
}
// optimisticLockingExample demonstrates using SetIFDEQ for optimistic locking
func optimisticLockingExample(ctx context.Context, rdb *redis.Client) {
key := "counter"
// Initial value
rdb.Set(ctx, key, "100", 0)
fmt.Printf("Initial value: %s\n", rdb.Get(ctx, key).Val())
// Get current digest
currentDigest := rdb.Digest(ctx, key).Val()
fmt.Printf("Current digest: 0x%016x\n", currentDigest)
// Simulate some processing time
time.Sleep(100 * time.Millisecond)
// Try to update only if value hasn't changed (digest matches)
newValue := "150"
result := rdb.SetIFDEQ(ctx, key, newValue, currentDigest, 0)
if result.Err() == redis.Nil {
fmt.Println("✗ Update failed: value was modified by another client")
} else if result.Err() != nil {
fmt.Printf("✗ Error: %v\n", result.Err())
} else {
fmt.Printf("✓ Update successful! New value: %s\n", rdb.Get(ctx, key).Val())
}
// Try again with wrong digest (simulating concurrent modification)
wrongDigest := uint64(12345)
result = rdb.SetIFDEQ(ctx, key, "200", wrongDigest, 0)
if result.Err() == redis.Nil {
fmt.Println("✓ Correctly rejected update with wrong digest")
}
}
// detectChangesExample demonstrates using SetIFDNE to detect if a value changed
func detectChangesExample(ctx context.Context, rdb *redis.Client) {
key := "config:version"
// Set initial value
oldValue := "v1.0.0"
rdb.Set(ctx, key, oldValue, 0)
fmt.Printf("Initial value: %s\n", oldValue)
// Calculate digest of a DIFFERENT value (what we expect it NOT to be)
unwantedValue := "v0.9.0"
unwantedDigest := xxh3.HashString(unwantedValue)
fmt.Printf("Unwanted value digest: 0x%016x\n", unwantedDigest)
// Update to new value only if current value is NOT the unwanted value
// (i.e., only if digest does NOT match unwantedDigest)
newValue := "v2.0.0"
result := rdb.SetIFDNE(ctx, key, newValue, unwantedDigest, 0)
if result.Err() == redis.Nil {
fmt.Println("✗ Current value matches unwanted value (digest matches)")
} else if result.Err() != nil {
fmt.Printf("✗ Error: %v\n", result.Err())
} else {
fmt.Printf("✓ Current value is different from unwanted value! Updated to: %s\n", rdb.Get(ctx, key).Val())
}
// Try to update again, but this time the digest matches current value (should fail)
currentDigest := rdb.Digest(ctx, key).Val()
result = rdb.SetIFDNE(ctx, key, "v3.0.0", currentDigest, 0)
if result.Err() == redis.Nil {
fmt.Println("✓ Correctly rejected: current value matches the digest (IFDNE failed)")
}
}
// conditionalDeleteExample demonstrates using DelExArgs with digest
func conditionalDeleteExample(ctx context.Context, rdb *redis.Client) {
key := "session:abc123"
value := "user_data_here"
// Set a value
rdb.Set(ctx, key, value, 0)
fmt.Printf("Created session: %s\n", key)
// Calculate expected digest
expectedDigest := xxh3.HashString(value)
fmt.Printf("Expected digest: 0x%016x\n", expectedDigest)
// Try to delete with wrong digest (should fail)
wrongDigest := uint64(99999)
deleted := rdb.DelExArgs(ctx, key, redis.DelExArgs{
Mode: "IFDEQ",
MatchDigest: wrongDigest,
}).Val()
if deleted == 0 {
fmt.Println("✓ Correctly refused to delete (wrong digest)")
}
// Delete with correct digest (should succeed)
deleted = rdb.DelExArgs(ctx, key, redis.DelExArgs{
Mode: "IFDEQ",
MatchDigest: expectedDigest,
}).Val()
if deleted == 1 {
fmt.Println("✓ Successfully deleted with correct digest")
}
// Verify deletion
exists := rdb.Exists(ctx, key).Val()
if exists == 0 {
fmt.Println("✓ Session deleted")
}
}
// clientSideDigestExample demonstrates calculating digests without fetching from Redis
func clientSideDigestExample(ctx context.Context, rdb *redis.Client) {
key := "product:1001:price"
// Scenario: We know the expected current value
expectedCurrentValue := "29.99"
newValue := "24.99"
// Set initial value
rdb.Set(ctx, key, expectedCurrentValue, 0)
fmt.Printf("Current price: $%s\n", expectedCurrentValue)
// Calculate digest client-side (no need to fetch from Redis!)
expectedDigest := xxh3.HashString(expectedCurrentValue)
fmt.Printf("Expected digest (calculated client-side): 0x%016x\n", expectedDigest)
// Update price only if it matches our expectation
result := rdb.SetIFDEQ(ctx, key, newValue, expectedDigest, 0)
if result.Err() == redis.Nil {
fmt.Println("✗ Price was already changed by someone else")
actualValue := rdb.Get(ctx, key).Val()
fmt.Printf(" Actual current price: $%s\n", actualValue)
} else if result.Err() != nil {
fmt.Printf("✗ Error: %v\n", result.Err())
} else {
fmt.Printf("✓ Price updated successfully to $%s\n", newValue)
}
// Demonstrate with binary data
fmt.Println("\nBinary data example:")
binaryKey := "image:thumbnail"
binaryData := []byte{0xFF, 0xD8, 0xFF, 0xE0} // JPEG header
rdb.Set(ctx, binaryKey, binaryData, 0)
// Calculate digest for binary data
binaryDigest := xxh3.Hash(binaryData)
fmt.Printf("Binary data digest: 0x%016x\n", binaryDigest)
// Verify it matches Redis
redisDigest := rdb.Digest(ctx, binaryKey).Val()
if binaryDigest == redisDigest {
fmt.Println("✓ Binary digest matches!")
}
}

3
internal/auth/streaming/pool_hook.go
View File

@@ -190,7 +190,8 @@ func (r *ReAuthPoolHook) OnPut(_ context.Context, conn *pool.Conn) (bool, bool,
return
}
_, err := stateMachine.AwaitAndTransition(ctx, []pool.ConnState{pool.StateIdle}, pool.StateUnusable)
// Use predefined slice to avoid allocation
_, err := stateMachine.AwaitAndTransition(ctx, pool.ValidFromIdle(), pool.StateUnusable)
if err != nil {
// Timeout or other error occurred, cannot acquire connection
reAuthFn(err)

32
internal/pool/conn.go
View File

@@ -18,6 +18,15 @@ import (
var noDeadline = time.Time{}
// Preallocated errors for hot paths to avoid allocations
var (
errAlreadyMarkedForHandoff = errors.New("connection is already marked for handoff")
errNotMarkedForHandoff = errors.New("connection was not marked for handoff")
errHandoffStateChanged = errors.New("handoff state changed during marking")
errConnectionNotAvailable = errors.New("redis: connection not available")
errConnNotAvailableForWrite = errors.New("redis: connection not available for write operation")
)
// Global time cache updated every 50ms by background goroutine.
// This avoids expensive time.Now() syscalls in hot paths like getEffectiveReadTimeout.
// Max staleness: 50ms, which is acceptable for timeout deadline checks (timeouts are typically 3-30 seconds).
@@ -228,16 +237,18 @@ func (cn *Conn) CompareAndSwapUsable(old, new bool) bool {
if new {
// Trying to make usable - transition from UNUSABLE to IDLE
// This should only work from UNUSABLE or INITIALIZING states
// Use predefined slice to avoid allocation
_, err := cn.stateMachine.TryTransition(
[]ConnState{StateInitializing, StateUnusable},
validFromInitializingOrUnusable,
StateIdle,
)
return err == nil
} else {
// Trying to make unusable - transition from IDLE to UNUSABLE
// This is typically for acquiring the connection for background operations
// Use predefined slice to avoid allocation
_, err := cn.stateMachine.TryTransition(
[]ConnState{StateIdle},
validFromIdle,
StateUnusable,
)
return err == nil
@@ -610,9 +621,10 @@ func (cn *Conn) SetNetConnAndInitConn(ctx context.Context, netConn net.Conn) err
}
waitCtx, cancel := context.WithDeadline(ctx, deadline)
defer cancel()
// Use predefined slice to avoid allocation
finalState, err := cn.stateMachine.AwaitAndTransition(
waitCtx,
[]ConnState{StateCreated, StateIdle, StateUnusable},
validFromCreatedIdleOrUnusable,
StateInitializing,
)
if err != nil {
@@ -643,7 +655,7 @@ func (cn *Conn) SetNetConnAndInitConn(ctx context.Context, netConn net.Conn) err
func (cn *Conn) MarkForHandoff(newEndpoint string, seqID int64) error {
// Check if already marked for handoff
if cn.ShouldHandoff() {
return errors.New("connection is already marked for handoff")
return errAlreadyMarkedForHandoff
}
// Set handoff metadata atomically
@@ -663,12 +675,12 @@ func (cn *Conn) MarkQueuedForHandoff() error {
// Get current handoff state
currentState := cn.handoffStateAtomic.Load()
if currentState == nil {
return errors.New("connection was not marked for handoff")
return errNotMarkedForHandoff
}
state := currentState.(*HandoffState)
if !state.ShouldHandoff {
return errors.New("connection was not marked for handoff")
return errNotMarkedForHandoff
}
// Create new state with ShouldHandoff=false but preserve endpoint and seqID
@@ -683,7 +695,7 @@ func (cn *Conn) MarkQueuedForHandoff() error {
// Atomic compare-and-swap to update state
if !cn.handoffStateAtomic.CompareAndSwap(currentState, newState) {
// State changed between load and CAS - retry or return error
return errors.New("handoff state changed during marking")
return errHandoffStateChanged
}
// Transition to UNUSABLE from IN_USE (normal flow), IDLE (edge cases), or CREATED (tests/uninitialized)
@@ -822,7 +834,7 @@ func (cn *Conn) WithReader(
// Get the connection directly from atomic storage
netConn := cn.getNetConn()
if netConn == nil {
return fmt.Errorf("redis: connection not available")
return errConnectionNotAvailable
}
if err := netConn.SetReadDeadline(cn.deadline(ctx, effectiveTimeout)); err != nil {
@@ -845,8 +857,8 @@ func (cn *Conn) WithWriter(
return err
}
} else {
// Connection is not available - return error
return fmt.Errorf("redis: conn[%d] not available for write operation", cn.GetID())
// Connection is not available - return preallocated error
return errConnNotAvailableForWrite
}
}

23
internal/pool/conn_state.go
View File

@@ -46,8 +46,28 @@ var (
validFromInUse = []ConnState{StateInUse}
validFromCreatedOrIdle = []ConnState{StateCreated, StateIdle}
validFromCreatedInUseOrIdle = []ConnState{StateCreated, StateInUse, StateIdle}
// For AwaitAndTransition calls
validFromCreatedIdleOrUnusable = []ConnState{StateCreated, StateIdle, StateUnusable}
validFromIdle = []ConnState{StateIdle}
// For CompareAndSwapUsable
validFromInitializingOrUnusable = []ConnState{StateInitializing, StateUnusable}
)
// Accessor functions for predefined slices to avoid allocations in external packages
// These return the same slice instance, so they're zero-allocation
// ValidFromIdle returns a predefined slice containing only StateIdle.
// Use this to avoid allocations when calling AwaitAndTransition or TryTransition.
func ValidFromIdle() []ConnState {
return validFromIdle
}
// ValidFromCreatedIdleOrUnusable returns a predefined slice for initialization transitions.
// Use this to avoid allocations when calling AwaitAndTransition or TryTransition.
func ValidFromCreatedIdleOrUnusable() []ConnState {
return validFromCreatedIdleOrUnusable
}
// String returns a human-readable string representation of the state.
func (s ConnState) String() string {
switch s {
@@ -300,7 +320,8 @@ func (sm *ConnStateMachine) notifyWaiters() {
processed = true
break
} else {
// State changed - re-add waiter to front of queue and retry
// State changed - re-add waiter to front of queue to maintain FIFO ordering
// This waiter was first in line and should retain priority
sm.waiters.PushFront(w)
sm.waiterCount.Add(1)
// Continue to next iteration to re-read state

169
internal/pool/conn_state_alloc_test.go Normal file
View File

@@ -0,0 +1,169 @@
package pool
import (
"context"
"testing"
)
// TestPredefinedSlicesAvoidAllocations verifies that using predefined slices
// avoids allocations in AwaitAndTransition calls
func TestPredefinedSlicesAvoidAllocations(t *testing.T) {
sm := NewConnStateMachine()
sm.Transition(StateIdle)
ctx := context.Background()
// Test with predefined slice - should have 0 allocations on fast path
allocs := testing.AllocsPerRun(100, func() {
_, _ = sm.AwaitAndTransition(ctx, validFromIdle, StateUnusable)
sm.Transition(StateIdle)
})
if allocs > 0 {
t.Errorf("Expected 0 allocations with predefined slice, got %.2f", allocs)
}
}
// TestInlineSliceAllocations shows that inline slices cause allocations
func TestInlineSliceAllocations(t *testing.T) {
sm := NewConnStateMachine()
sm.Transition(StateIdle)
ctx := context.Background()
// Test with inline slice - will allocate
allocs := testing.AllocsPerRun(100, func() {
_, _ = sm.AwaitAndTransition(ctx, []ConnState{StateIdle}, StateUnusable)
sm.Transition(StateIdle)
})
if allocs == 0 {
t.Logf("Inline slice had 0 allocations (compiler optimization)")
} else {
t.Logf("Inline slice caused %.2f allocations per run (expected)", allocs)
}
}
// BenchmarkAwaitAndTransition_PredefinedSlice benchmarks with predefined slice
func BenchmarkAwaitAndTransition_PredefinedSlice(b *testing.B) {
sm := NewConnStateMachine()
sm.Transition(StateIdle)
ctx := context.Background()
b.ResetTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
_, _ = sm.AwaitAndTransition(ctx, validFromIdle, StateUnusable)
sm.Transition(StateIdle)
}
}
// BenchmarkAwaitAndTransition_InlineSlice benchmarks with inline slice
func BenchmarkAwaitAndTransition_InlineSlice(b *testing.B) {
sm := NewConnStateMachine()
sm.Transition(StateIdle)
ctx := context.Background()
b.ResetTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
_, _ = sm.AwaitAndTransition(ctx, []ConnState{StateIdle}, StateUnusable)
sm.Transition(StateIdle)
}
}
// BenchmarkAwaitAndTransition_MultipleStates_Predefined benchmarks with predefined multi-state slice
func BenchmarkAwaitAndTransition_MultipleStates_Predefined(b *testing.B) {
sm := NewConnStateMachine()
sm.Transition(StateIdle)
ctx := context.Background()
b.ResetTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
_, _ = sm.AwaitAndTransition(ctx, validFromCreatedIdleOrUnusable, StateInitializing)
sm.Transition(StateIdle)
}
}
// BenchmarkAwaitAndTransition_MultipleStates_Inline benchmarks with inline multi-state slice
func BenchmarkAwaitAndTransition_MultipleStates_Inline(b *testing.B) {
sm := NewConnStateMachine()
sm.Transition(StateIdle)
ctx := context.Background()
b.ResetTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
_, _ = sm.AwaitAndTransition(ctx, []ConnState{StateCreated, StateIdle, StateUnusable}, StateInitializing)
sm.Transition(StateIdle)
}
}
// TestPreallocatedErrorsAvoidAllocations verifies that preallocated errors
// avoid allocations in hot paths
func TestPreallocatedErrorsAvoidAllocations(t *testing.T) {
cn := NewConn(nil)
// Test MarkForHandoff - first call should succeed
err := cn.MarkForHandoff("localhost:6379", 123)
if err != nil {
t.Fatalf("First MarkForHandoff should succeed: %v", err)
}
// Second call should return preallocated error with 0 allocations
allocs := testing.AllocsPerRun(100, func() {
_ = cn.MarkForHandoff("localhost:6380", 124)
})
if allocs > 0 {
t.Errorf("Expected 0 allocations for preallocated error, got %.2f", allocs)
}
}
// BenchmarkHandoffErrors_Preallocated benchmarks handoff errors with preallocated errors
func BenchmarkHandoffErrors_Preallocated(b *testing.B) {
cn := NewConn(nil)
cn.MarkForHandoff("localhost:6379", 123)
b.ResetTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
_ = cn.MarkForHandoff("localhost:6380", 124)
}
}
// BenchmarkCompareAndSwapUsable_Preallocated benchmarks with preallocated slices
func BenchmarkCompareAndSwapUsable_Preallocated(b *testing.B) {
cn := NewConn(nil)
cn.stateMachine.Transition(StateIdle)
b.ResetTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
cn.CompareAndSwapUsable(true, false) // IDLE -> UNUSABLE
cn.CompareAndSwapUsable(false, true) // UNUSABLE -> IDLE
}
}
// TestAllTryTransitionUsePredefinedSlices verifies all TryTransition calls use predefined slices
func TestAllTryTransitionUsePredefinedSlices(t *testing.T) {
cn := NewConn(nil)
cn.stateMachine.Transition(StateIdle)
// Test CompareAndSwapUsable - should have minimal allocations
allocs := testing.AllocsPerRun(100, func() {
cn.CompareAndSwapUsable(true, false) // IDLE -> UNUSABLE
cn.CompareAndSwapUsable(false, true) // UNUSABLE -> IDLE
})
// Allow some allocations for error objects, but should be minimal
if allocs > 2 {
t.Errorf("Expected <= 2 allocations with predefined slices, got %.2f", allocs)
}
}

46
internal/pool/conn_state_test.go
View File

@@ -401,32 +401,16 @@ func TestConnStateMachine_FIFOOrdering(t *testing.T) {
var orderMu sync.Mutex
var wg sync.WaitGroup
// Use channels to ensure deterministic queueing order
// Each goroutine waits for the previous one to queue before it queues
queuedChannels := make([]chan struct{}, numGoroutines)
for i := 0; i < numGoroutines; i++ {
queuedChannels[i] = make(chan struct{})
}
// Launch goroutines that will all wait
// Launch goroutines one at a time, ensuring each is queued before launching the next
for i := 0; i < numGoroutines; i++ {
wg.Add(1)
expectedWaiters := int32(i + 1)
go func(id int) {
defer wg.Done()
// Wait for previous goroutine to queue (except for goroutine 0)
if id > 0 {
<-queuedChannels[id-1]
}
// Small delay to ensure the previous goroutine's AwaitAndTransition has been called
time.Sleep(5 * time.Millisecond)
ctx := context.Background()
// Signal that we're about to queue
close(queuedChannels[id])
// This should queue in FIFO order
_, err := sm.AwaitAndTransition(ctx, []ConnState{StateIdle}, StateInitializing)
if err != nil {
@@ -441,16 +425,30 @@ func TestConnStateMachine_FIFOOrdering(t *testing.T) {
t.Logf("Goroutine %d: executed (position %d)", id, len(executionOrder))
// Transition back to READY to allow next waiter
// Transition back to IDLE to allow next waiter
sm.Transition(StateIdle)
}(i)
// Wait until this goroutine has been queued before launching the next
// Poll the waiter count to ensure the goroutine is actually queued
timeout := time.After(100 * time.Millisecond)
for {
if sm.waiterCount.Load() >= expectedWaiters {
break
}
select {
case <-timeout:
t.Fatalf("Timeout waiting for goroutine %d to queue", i)
case <-time.After(1 * time.Millisecond):
// Continue polling
}
}
}
// Wait for all goroutines to queue up
<-queuedChannels[numGoroutines-1]
time.Sleep(50 * time.Millisecond)
// Give all goroutines time to fully settle in the queue
time.Sleep(10 * time.Millisecond)
// Transition to READY to start processing the queue
// Transition to IDLE to start processing the queue
sm.Transition(StateIdle)
wg.Wait()

289
internal/semaphore.go
View File

@@ -15,147 +15,318 @@ var semTimers = sync.Pool{
},
}
// FastSemaphore is a counting semaphore implementation using atomic operations.
// waiter represents a goroutine waiting for a token.
type waiter struct {
ready chan struct{}
next *waiter
cancelled atomic.Bool // Set to true if this waiter was cancelled/timed out
notified atomic.Bool // Set to true when Release() notifies this waiter
}
// FastSemaphore is a counting semaphore implementation using a hybrid approach.
// It's optimized for the fast path (no blocking) while still supporting timeouts and context cancellation.
//
// This implementation uses a buffered channel for the fast path (TryAcquire/Release without waiters)
// and a FIFO queue for waiters to ensure fairness.
//
// Performance characteristics:
// - Fast path (no blocking): Single atomic CAS operation
// - Slow path (blocking): Falls back to channel-based waiting
// - Release: Single atomic decrement + optional channel notification
// - Fast path (no blocking): Single channel operation (very fast)
// - Slow path (blocking): FIFO queue-based waiting
// - Release: Channel send or wake up first waiter in queue
//
// This is significantly faster than a pure channel-based semaphore because:
// 1. The fast path avoids channel operations entirely (no scheduler involvement)
// 2. Atomic operations are much cheaper than channel send/receive
// 1. The fast path uses a buffered channel (single atomic operation)
// 2. FIFO ordering prevents starvation for waiters
// 3. Waiters don't compete with TryAcquire callers
type FastSemaphore struct {
// Current number of acquired tokens (atomic)
count atomic.Int32
// Buffered channel for fast path (TryAcquire/Release)
tokens chan struct{}
// Maximum number of tokens (capacity)
max int32
// Channel for blocking waiters
// Only used when fast path fails (semaphore is full)
waitCh chan struct{}
// Mutex to protect the waiter queue
lock sync.Mutex
// Head and tail of the waiter queue (FIFO)
head *waiter
tail *waiter
}
// NewFastSemaphore creates a new fast semaphore with the given capacity.
func NewFastSemaphore(capacity int32) *FastSemaphore {
ch := make(chan struct{}, capacity)
// Fill the channel with tokens (available slots)
for i := int32(0); i < capacity; i++ {
ch <- struct{}{}
}
return &FastSemaphore{
max: capacity,
waitCh: make(chan struct{}, capacity),
tokens: ch,
}
}
// TryAcquire attempts to acquire a token without blocking.
// Returns true if successful, false if the semaphore is full.
//
// This is the fast path - just a single CAS operation.
// This is the fast path - just a single channel operation.
func (s *FastSemaphore) TryAcquire() bool {
for {
current := s.count.Load()
if current >= s.max {
return false // Semaphore is full
select {
case <-s.tokens:
return true
default:
return false
}
if s.count.CompareAndSwap(current, current+1) {
return true // Successfully acquired
}
// CAS failed due to concurrent modification, retry
// enqueue adds a waiter to the end of the queue.
// Must be called with lock held.
func (s *FastSemaphore) enqueue(w *waiter) {
if s.tail == nil {
s.head = w
s.tail = w
} else {
s.tail.next = w
s.tail = w
}
}
// dequeue removes and returns the first waiter from the queue.
// Must be called with lock held.
// Returns nil if the queue is empty.
func (s *FastSemaphore) dequeue() *waiter {
if s.head == nil {
return nil
}
w := s.head
s.head = w.next
if s.head == nil {
s.tail = nil
}
w.next = nil
return w
}
// notifyOne wakes up the first waiter in the queue if any.
func (s *FastSemaphore) notifyOne() {
s.lock.Lock()
w := s.dequeue()
s.lock.Unlock()
if w != nil {
close(w.ready)
}
}
// Acquire acquires a token, blocking if necessary until one is available or the context is cancelled.
// Returns an error if the context is cancelled or the timeout expires.
// Returns timeoutErr when the timeout expires.
//
// Performance optimization:
// 1. First try fast path (no blocking)
// 2. If that fails, fall back to channel-based waiting
func (s *FastSemaphore) Acquire(ctx context.Context, timeout time.Duration, timeoutErr error) error {
// Fast path: try to acquire without blocking
// Check context first
select {
case <-ctx.Done():
return ctx.Err()
default:
}
// Try fast acquire first
if s.TryAcquire() {
// Try fast path first (non-blocking channel receive)
select {
case <-s.tokens:
return nil
default:
// Channel is empty, need to wait
}
// Fast path failed, need to wait
// Need to wait - create a waiter and add to queue
w := &waiter{
ready: make(chan struct{}),
}
s.lock.Lock()
s.enqueue(w)
s.lock.Unlock()
// Use timer pool to avoid allocation
timer := semTimers.Get().(*time.Timer)
defer semTimers.Put(timer)
timer.Reset(timeout)
start := time.Now()
for {
select {
case <-ctx.Done():
if !timer.Stop() {
<-timer.C
}
return ctx.Err()
// Mark as cancelled and try to claim ourselves
w.cancelled.Store(true)
if w.notified.CompareAndSwap(false, true) {
// We successfully claimed ourselves, we're cancelling
// Try to remove from queue
s.lock.Lock()
removed := s.removeWaiter(w)
s.lock.Unlock()
case <-s.waitCh:
// Someone released a token, try to acquire it
if s.TryAcquire() {
if !removed {
// Already dequeued, wait for ready to be closed
<-w.ready
}
// We claimed it, so no token was given to us
return ctx.Err()
} else {
// Release() already claimed us and is giving us a token
// Wait for the notification and then release the token
<-w.ready
s.releaseToPool()
return ctx.Err()
}
case <-w.ready:
// We were notified and got the token
// Stop the timer and drain it if it already fired
if !timer.Stop() {
<-timer.C
}
// We have the token, just return
return nil
}
// Failed to acquire (race with another goroutine), continue waiting
case <-timer.C:
// Mark as cancelled and try to claim ourselves
w.cancelled.Store(true)
if w.notified.CompareAndSwap(false, true) {
// We successfully claimed ourselves, we're cancelling
// Try to remove from queue
s.lock.Lock()
removed := s.removeWaiter(w)
s.lock.Unlock()
if !removed {
// Already dequeued, wait for ready to be closed
<-w.ready
}
// We claimed it, so no token was given to us
return timeoutErr
} else {
// Release() already claimed us and is giving us a token
// Wait for the notification and then release the token
<-w.ready
s.releaseToPool()
return timeoutErr
}
}
}
// Periodically check if we can acquire (handles race conditions)
if time.Since(start) > timeout {
return timeoutErr
// removeWaiter removes a waiter from the queue.
// Must be called with lock held.
// Returns true if the waiter was found and removed, false otherwise.
func (s *FastSemaphore) removeWaiter(target *waiter) bool {
if s.head == nil {
return false
}
// Special case: removing head
if s.head == target {
s.head = target.next
if s.head == nil {
s.tail = nil
}
return true
}
// Find and remove from middle or tail
prev := s.head
for prev.next != nil {
if prev.next == target {
prev.next = target.next
if prev.next == nil {
s.tail = prev
}
return true
}
prev = prev.next
}
return false
}
// AcquireBlocking acquires a token, blocking indefinitely until one is available.
// This is useful for cases where you don't need timeout or context cancellation.
// Returns immediately if a token is available (fast path).
func (s *FastSemaphore) AcquireBlocking() {
// Try fast path first
if s.TryAcquire() {
// Try fast path first (non-blocking channel receive)
select {
case <-s.tokens:
return
default:
// Channel is empty, need to wait
}
// Slow path: wait for a token
for {
<-s.waitCh
if s.TryAcquire() {
return
// Need to wait - create a waiter and add to queue
w := &waiter{
ready: make(chan struct{}),
}
// Failed to acquire (race with another goroutine), continue waiting
s.lock.Lock()
s.enqueue(w)
s.lock.Unlock()
// Wait to be notified
<-w.ready
}
// releaseToPool releases a token back to the pool.
// This should be called when a waiter was notified but then cancelled/timed out.
// We need to pass the token to another waiter if any, otherwise put it back in the channel.
func (s *FastSemaphore) releaseToPool() {
s.lock.Lock()
w := s.dequeue()
s.lock.Unlock()
if w != nil {
// Transfer the token to another waiter
close(w.ready)
} else {
// No waiters, put the token back in the channel
s.tokens <- struct{}{}
}
}
// Release releases a token back to the semaphore.
// This wakes up one waiting goroutine if any are blocked.
// This wakes up the first waiting goroutine if any are blocked.
func (s *FastSemaphore) Release() {
s.count.Add(-1)
// Try to give the token to a waiter first
for {
s.lock.Lock()
w := s.dequeue()
s.lock.Unlock()
// Try to wake up a waiter (non-blocking)
// If no one is waiting, this is a no-op
select {
case s.waitCh <- struct{}{}:
// Successfully notified a waiter
default:
// No waiters, that's fine
if w == nil {
// No waiters, put the token back in the channel
s.tokens <- struct{}{}
return
}
// Check if this waiter was cancelled before we notify them
if w.cancelled.Load() {
// This waiter was cancelled, skip them and try the next one
// We still have the token, so continue the loop
close(w.ready) // Still need to close to unblock them
continue
}
// Try to claim this waiter by setting notified flag
// If the waiter is being cancelled concurrently, one of us will win
if !w.notified.CompareAndSwap(false, true) {
// Someone else (the waiter itself) already claimed it
// This means the waiter is cancelling, skip to next
close(w.ready) // Still need to close to unblock them
continue
}
// We successfully claimed the waiter, transfer the token
close(w.ready)
return
}
}
// Len returns the current number of acquired tokens.
// Used by tests to check semaphore state.
func (s *FastSemaphore) Len() int32 {
return s.count.Load()
// Number of acquired tokens = max - available tokens in channel
return s.max - int32(len(s.tokens))
}

245
internal/semaphore_bench_test.go Normal file
View File

@@ -0,0 +1,245 @@
package internal
import (
"context"
"sync"
"testing"
"time"
)
// channelSemaphore is a simple semaphore using a buffered channel
type channelSemaphore struct {
ch chan struct{}
}
func newChannelSemaphore(capacity int) *channelSemaphore {
return &channelSemaphore{
ch: make(chan struct{}, capacity),
}
}
func (s *channelSemaphore) TryAcquire() bool {
select {
case s.ch <- struct{}{}:
return true
default:
return false
}
}
func (s *channelSemaphore) Acquire(ctx context.Context, timeout time.Duration) error {
timer := time.NewTimer(timeout)
defer timer.Stop()
select {
case s.ch <- struct{}{}:
return nil
case <-ctx.Done():
return ctx.Err()
case <-timer.C:
return context.DeadlineExceeded
}
}
func (s *channelSemaphore) AcquireBlocking() {
s.ch <- struct{}{}
}
func (s *channelSemaphore) Release() {
<-s.ch
}
// Benchmarks for FastSemaphore
func BenchmarkFastSemaphore_TryAcquire(b *testing.B) {
sem := NewFastSemaphore(100)
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
if sem.TryAcquire() {
sem.Release()
}
}
})
}
func BenchmarkFastSemaphore_AcquireRelease(b *testing.B) {
sem := NewFastSemaphore(100)
ctx := context.Background()
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
sem.Acquire(ctx, time.Second, context.DeadlineExceeded)
sem.Release()
}
})
}
func BenchmarkFastSemaphore_Contention(b *testing.B) {
sem := NewFastSemaphore(10) // Small capacity to create contention
ctx := context.Background()
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
sem.Acquire(ctx, time.Second, context.DeadlineExceeded)
sem.Release()
}
})
}
func BenchmarkFastSemaphore_HighContention(b *testing.B) {
sem := NewFastSemaphore(1) // Very high contention
ctx := context.Background()
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
sem.Acquire(ctx, time.Second, context.DeadlineExceeded)
sem.Release()
}
})
}
// Benchmarks for channelSemaphore
func BenchmarkChannelSemaphore_TryAcquire(b *testing.B) {
sem := newChannelSemaphore(100)
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
if sem.TryAcquire() {
sem.Release()
}
}
})
}
func BenchmarkChannelSemaphore_AcquireRelease(b *testing.B) {
sem := newChannelSemaphore(100)
ctx := context.Background()
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
sem.Acquire(ctx, time.Second)
sem.Release()
}
})
}
func BenchmarkChannelSemaphore_Contention(b *testing.B) {
sem := newChannelSemaphore(10) // Small capacity to create contention
ctx := context.Background()
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
sem.Acquire(ctx, time.Second)
sem.Release()
}
})
}
func BenchmarkChannelSemaphore_HighContention(b *testing.B) {
sem := newChannelSemaphore(1) // Very high contention
ctx := context.Background()
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
sem.Acquire(ctx, time.Second)
sem.Release()
}
})
}
// Benchmark with realistic workload (some work between acquire/release)
func BenchmarkFastSemaphore_WithWork(b *testing.B) {
sem := NewFastSemaphore(10)
ctx := context.Background()
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
sem.Acquire(ctx, time.Second, context.DeadlineExceeded)
// Simulate some work
_ = make([]byte, 64)
sem.Release()
}
})
}
func BenchmarkChannelSemaphore_WithWork(b *testing.B) {
sem := newChannelSemaphore(10)
ctx := context.Background()
b.ResetTimer()
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
sem.Acquire(ctx, time.Second)
// Simulate some work
_ = make([]byte, 64)
sem.Release()
}
})
}
// Benchmark mixed TryAcquire and Acquire
func BenchmarkFastSemaphore_Mixed(b *testing.B) {
sem := NewFastSemaphore(10)
ctx := context.Background()
var wg sync.WaitGroup
b.ResetTimer()
// Half goroutines use TryAcquire
wg.Add(1)
go func() {
defer wg.Done()
for i := 0; i < b.N/2; i++ {
if sem.TryAcquire() {
sem.Release()
}
}
}()
// Half goroutines use Acquire
wg.Add(1)
go func() {
defer wg.Done()
for i := 0; i < b.N/2; i++ {
sem.Acquire(ctx, time.Second, context.DeadlineExceeded)
sem.Release()
}
}()
wg.Wait()
}
func BenchmarkChannelSemaphore_Mixed(b *testing.B) {
sem := newChannelSemaphore(10)
ctx := context.Background()
var wg sync.WaitGroup
b.ResetTimer()
// Half goroutines use TryAcquire
wg.Add(1)
go func() {
defer wg.Done()
for i := 0; i < b.N/2; i++ {
if sem.TryAcquire() {
sem.Release()
}
}
}()
// Half goroutines use Acquire
wg.Add(1)
go func() {
defer wg.Done()
for i := 0; i < b.N/2; i++ {
sem.Acquire(ctx, time.Second)
sem.Release()
}
}()
wg.Wait()
}

344
string_commands.go
View File

@@ -2,6 +2,7 @@ package redis
import (
"context"
"fmt"
"time"
)
@@ -9,6 +10,8 @@ type StringCmdable interface {
Append(ctx context.Context, key, value string) *IntCmd
Decr(ctx context.Context, key string) *IntCmd
DecrBy(ctx context.Context, key string, decrement int64) *IntCmd
DelExArgs(ctx context.Context, key string, a DelExArgs) *IntCmd
Digest(ctx context.Context, key string) *DigestCmd
Get(ctx context.Context, key string) *StringCmd
GetRange(ctx context.Context, key string, start, end int64) *StringCmd
GetSet(ctx context.Context, key string, value interface{}) *StringCmd
@@ -25,6 +28,14 @@ type StringCmdable interface {
Set(ctx context.Context, key string, value interface{}, expiration time.Duration) *StatusCmd
SetArgs(ctx context.Context, key string, value interface{}, a SetArgs) *StatusCmd
SetEx(ctx context.Context, key string, value interface{}, expiration time.Duration) *StatusCmd
SetIFEQ(ctx context.Context, key string, value interface{}, matchValue interface{}, expiration time.Duration) *StatusCmd
SetIFEQGet(ctx context.Context, key string, value interface{}, matchValue interface{}, expiration time.Duration) *StringCmd
SetIFNE(ctx context.Context, key string, value interface{}, matchValue interface{}, expiration time.Duration) *StatusCmd
SetIFNEGet(ctx context.Context, key string, value interface{}, matchValue interface{}, expiration time.Duration) *StringCmd
SetIFDEQ(ctx context.Context, key string, value interface{}, matchDigest uint64, expiration time.Duration) *StatusCmd
SetIFDEQGet(ctx context.Context, key string, value interface{}, matchDigest uint64, expiration time.Duration) *StringCmd
SetIFDNE(ctx context.Context, key string, value interface{}, matchDigest uint64, expiration time.Duration) *StatusCmd
SetIFDNEGet(ctx context.Context, key string, value interface{}, matchDigest uint64, expiration time.Duration) *StringCmd
SetNX(ctx context.Context, key string, value interface{}, expiration time.Duration) *BoolCmd
SetXX(ctx context.Context, key string, value interface{}, expiration time.Duration) *BoolCmd
SetRange(ctx context.Context, key string, offset int64, value string) *IntCmd
@@ -49,6 +60,70 @@ func (c cmdable) DecrBy(ctx context.Context, key string, decrement int64) *IntCm
return cmd
}
// DelExArgs provides arguments for the DelExArgs function.
type DelExArgs struct {
// Mode can be `IFEQ`, `IFNE`, `IFDEQ`, or `IFDNE`.
Mode string
// MatchValue is used with IFEQ/IFNE modes for compare-and-delete operations.
// - IFEQ: only delete if current value equals MatchValue
// - IFNE: only delete if current value does not equal MatchValue
MatchValue interface{}
// MatchDigest is used with IFDEQ/IFDNE modes for digest-based compare-and-delete.
// - IFDEQ: only delete if current value's digest equals MatchDigest
// - IFDNE: only delete if current value's digest does not equal MatchDigest
//
// The digest is a uint64 xxh3 hash value.
//
// For examples of client-side digest generation, see:
// example/digest-optimistic-locking/
MatchDigest uint64
}
// DelExArgs Redis `DELEX key [IFEQ|IFNE|IFDEQ|IFDNE] match-value` command.
// Compare-and-delete with flexible conditions.
//
// Returns the number of keys that were removed (0 or 1).
func (c cmdable) DelExArgs(ctx context.Context, key string, a DelExArgs) *IntCmd {
args := []interface{}{"delex", key}
if a.Mode != "" {
args = append(args, a.Mode)
// Add match value/digest based on mode
switch a.Mode {
case "ifeq", "IFEQ", "ifne", "IFNE":
if a.MatchValue != nil {
args = append(args, a.MatchValue)
}
case "ifdeq", "IFDEQ", "ifdne", "IFDNE":
if a.MatchDigest != 0 {
args = append(args, fmt.Sprintf("%016x", a.MatchDigest))
}
}
}
cmd := NewIntCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
// Digest returns the xxh3 hash (uint64) of the specified key's value.
//
// The digest is a 64-bit xxh3 hash that can be used for optimistic locking
// with SetIFDEQ, SetIFDNE, and DelExArgs commands.
//
// For examples of client-side digest generation and usage patterns, see:
// example/digest-optimistic-locking/
//
// Redis 8.4+. See https://redis.io/commands/digest/
func (c cmdable) Digest(ctx context.Context, key string) *DigestCmd {
cmd := NewDigestCmd(ctx, "digest", key)
_ = c(ctx, cmd)
return cmd
}
// Get Redis `GET key` command. It returns redis.Nil error when key does not exist.
func (c cmdable) Get(ctx context.Context, key string) *StringCmd {
cmd := newStringCmd2(ctx, "get", key)
@@ -266,9 +341,24 @@ func (c cmdable) Set(ctx context.Context, key string, value interface{}, expirat
// SetArgs provides arguments for the SetArgs function.
type SetArgs struct {
// Mode can be `NX` or `XX` or empty.
// Mode can be `NX`, `XX`, `IFEQ`, `IFNE`, `IFDEQ`, `IFDNE` or empty.
Mode string
// MatchValue is used with IFEQ/IFNE modes for compare-and-set operations.
// - IFEQ: only set if current value equals MatchValue
// - IFNE: only set if current value does not equal MatchValue
MatchValue interface{}
// MatchDigest is used with IFDEQ/IFDNE modes for digest-based compare-and-set.
// - IFDEQ: only set if current value's digest equals MatchDigest
// - IFDNE: only set if current value's digest does not equal MatchDigest
//
// The digest is a uint64 xxh3 hash value.
//
// For examples of client-side digest generation, see:
// example/digest-optimistic-locking/
MatchDigest uint64
// Zero `TTL` or `Expiration` means that the key has no expiration time.
TTL time.Duration
ExpireAt time.Time
@@ -304,6 +394,18 @@ func (c cmdable) SetArgs(ctx context.Context, key string, value interface{}, a S
if a.Mode != "" {
args = append(args, a.Mode)
// Add match value/digest for CAS modes
switch a.Mode {
case "ifeq", "IFEQ", "ifne", "IFNE":
if a.MatchValue != nil {
args = append(args, a.MatchValue)
}
case "ifdeq", "IFDEQ", "ifdne", "IFDNE":
if a.MatchDigest != 0 {
args = append(args, fmt.Sprintf("%016x", a.MatchDigest))
}
}
}
if a.Get {
@@ -371,6 +473,246 @@ func (c cmdable) SetXX(ctx context.Context, key string, value interface{}, expir
return cmd
}
// SetIFEQ Redis `SET key value [expiration] IFEQ match-value` command.
// Compare-and-set: only sets the value if the current value equals matchValue.
//
// Returns "OK" on success.
// Returns nil if the operation was aborted due to condition not matching.
// Zero expiration means the key has no expiration time.
func (c cmdable) SetIFEQ(ctx context.Context, key string, value interface{}, matchValue interface{}, expiration time.Duration) *StatusCmd {
args := []interface{}{"set", key, value}
if expiration > 0 {
if usePrecise(expiration) {
args = append(args, "px", formatMs(ctx, expiration))
} else {
args = append(args, "ex", formatSec(ctx, expiration))
}
} else if expiration == KeepTTL {
args = append(args, "keepttl")
}
args = append(args, "ifeq", matchValue)
cmd := NewStatusCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
// SetIFEQGet Redis `SET key value [expiration] IFEQ match-value GET` command.
// Compare-and-set with GET: only sets the value if the current value equals matchValue,
// and returns the previous value.
//
// Returns the previous value on success.
// Returns nil if the operation was aborted due to condition not matching.
// Zero expiration means the key has no expiration time.
func (c cmdable) SetIFEQGet(ctx context.Context, key string, value interface{}, matchValue interface{}, expiration time.Duration) *StringCmd {
args := []interface{}{"set", key, value}
if expiration > 0 {
if usePrecise(expiration) {
args = append(args, "px", formatMs(ctx, expiration))
} else {
args = append(args, "ex", formatSec(ctx, expiration))
}
} else if expiration == KeepTTL {
args = append(args, "keepttl")
}
args = append(args, "ifeq", matchValue, "get")
cmd := NewStringCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
// SetIFNE Redis `SET key value [expiration] IFNE match-value` command.
// Compare-and-set: only sets the value if the current value does not equal matchValue.
//
// Returns "OK" on success.
// Returns nil if the operation was aborted due to condition not matching.
// Zero expiration means the key has no expiration time.
func (c cmdable) SetIFNE(ctx context.Context, key string, value interface{}, matchValue interface{}, expiration time.Duration) *StatusCmd {
args := []interface{}{"set", key, value}
if expiration > 0 {
if usePrecise(expiration) {
args = append(args, "px", formatMs(ctx, expiration))
} else {
args = append(args, "ex", formatSec(ctx, expiration))
}
} else if expiration == KeepTTL {
args = append(args, "keepttl")
}
args = append(args, "ifne", matchValue)
cmd := NewStatusCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
// SetIFNEGet Redis `SET key value [expiration] IFNE match-value GET` command.
// Compare-and-set with GET: only sets the value if the current value does not equal matchValue,
// and returns the previous value.
//
// Returns the previous value on success.
// Returns nil if the operation was aborted due to condition not matching.
// Zero expiration means the key has no expiration time.
func (c cmdable) SetIFNEGet(ctx context.Context, key string, value interface{}, matchValue interface{}, expiration time.Duration) *StringCmd {
args := []interface{}{"set", key, value}
if expiration > 0 {
if usePrecise(expiration) {
args = append(args, "px", formatMs(ctx, expiration))
} else {
args = append(args, "ex", formatSec(ctx, expiration))
}
} else if expiration == KeepTTL {
args = append(args, "keepttl")
}
args = append(args, "ifne", matchValue, "get")
cmd := NewStringCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
// SetIFDEQ sets the value only if the current value's digest equals matchDigest.
//
// This is a compare-and-set operation using xxh3 digest for optimistic locking.
// The matchDigest parameter is a uint64 xxh3 hash value.
//
// Returns "OK" on success.
// Returns redis.Nil if the digest doesn't match (value was modified).
// Zero expiration means the key has no expiration time.
//
// For examples of client-side digest generation and usage patterns, see:
// example/digest-optimistic-locking/
//
// Redis 8.4+. See https://redis.io/commands/set/
func (c cmdable) SetIFDEQ(ctx context.Context, key string, value interface{}, matchDigest uint64, expiration time.Duration) *StatusCmd {
args := []interface{}{"set", key, value}
if expiration > 0 {
if usePrecise(expiration) {
args = append(args, "px", formatMs(ctx, expiration))
} else {
args = append(args, "ex", formatSec(ctx, expiration))
}
} else if expiration == KeepTTL {
args = append(args, "keepttl")
}
args = append(args, "ifdeq", fmt.Sprintf("%016x", matchDigest))
cmd := NewStatusCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
// SetIFDEQGet sets the value only if the current value's digest equals matchDigest,
// and returns the previous value.
//
// This is a compare-and-set operation using xxh3 digest for optimistic locking.
// The matchDigest parameter is a uint64 xxh3 hash value.
//
// Returns the previous value on success.
// Returns redis.Nil if the digest doesn't match (value was modified).
// Zero expiration means the key has no expiration time.
//
// For examples of client-side digest generation and usage patterns, see:
// example/digest-optimistic-locking/
//
// Redis 8.4+. See https://redis.io/commands/set/
func (c cmdable) SetIFDEQGet(ctx context.Context, key string, value interface{}, matchDigest uint64, expiration time.Duration) *StringCmd {
args := []interface{}{"set", key, value}
if expiration > 0 {
if usePrecise(expiration) {
args = append(args, "px", formatMs(ctx, expiration))
} else {
args = append(args, "ex", formatSec(ctx, expiration))
}
} else if expiration == KeepTTL {
args = append(args, "keepttl")
}
args = append(args, "ifdeq", fmt.Sprintf("%016x", matchDigest), "get")
cmd := NewStringCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
// SetIFDNE sets the value only if the current value's digest does NOT equal matchDigest.
//
// This is a compare-and-set operation using xxh3 digest for optimistic locking.
// The matchDigest parameter is a uint64 xxh3 hash value.
//
// Returns "OK" on success (digest didn't match, value was set).
// Returns redis.Nil if the digest matches (value was not modified).
// Zero expiration means the key has no expiration time.
//
// For examples of client-side digest generation and usage patterns, see:
// example/digest-optimistic-locking/
//
// Redis 8.4+. See https://redis.io/commands/set/
func (c cmdable) SetIFDNE(ctx context.Context, key string, value interface{}, matchDigest uint64, expiration time.Duration) *StatusCmd {
args := []interface{}{"set", key, value}
if expiration > 0 {
if usePrecise(expiration) {
args = append(args, "px", formatMs(ctx, expiration))
} else {
args = append(args, "ex", formatSec(ctx, expiration))
}
} else if expiration == KeepTTL {
args = append(args, "keepttl")
}
args = append(args, "ifdne", fmt.Sprintf("%016x", matchDigest))
cmd := NewStatusCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
// SetIFDNEGet sets the value only if the current value's digest does NOT equal matchDigest,
// and returns the previous value.
//
// This is a compare-and-set operation using xxh3 digest for optimistic locking.
// The matchDigest parameter is a uint64 xxh3 hash value.
//
// Returns the previous value on success (digest didn't match, value was set).
// Returns redis.Nil if the digest matches (value was not modified).
// Zero expiration means the key has no expiration time.
//
// For examples of client-side digest generation and usage patterns, see:
// example/digest-optimistic-locking/
//
// Redis 8.4+. See https://redis.io/commands/set/
func (c cmdable) SetIFDNEGet(ctx context.Context, key string, value interface{}, matchDigest uint64, expiration time.Duration) *StringCmd {
args := []interface{}{"set", key, value}
if expiration > 0 {
if usePrecise(expiration) {
args = append(args, "px", formatMs(ctx, expiration))
} else {
args = append(args, "ex", formatSec(ctx, expiration))
}
} else if expiration == KeepTTL {
args = append(args, "keepttl")
}
args = append(args, "ifdne", fmt.Sprintf("%016x", matchDigest), "get")
cmd := NewStringCmd(ctx, args...)
_ = c(ctx, cmd)
return cmd
}
func (c cmdable) SetRange(ctx context.Context, key string, offset int64, value string) *IntCmd {
cmd := NewIntCmd(ctx, "setrange", key, offset, value)
_ = c(ctx, cmd)