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strobilstrobil
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feat(rueidisaside): add OverrideCacheTTL for custom TTL per cache entry (#922)
## Summary Adds `OverrideCacheTTL()` function to allow setting custom TTL for cache entries based on the data being cached. ## Use Case Enable different TTLs for positive vs negative cache entries: - Positive entries (data found): longer TTL (e.g., 5 minutes) - Negative entries (data not found): shorter TTL (e.g., 30 seconds) This prevents stale negative entries when data becomes available shortly after an initial miss. ## Usage ```go val, err := cache.Get(ctx, 5*time.Minute, key, func(ctx context.Context, key string) (string, error) { user, err := db.GetByID(ctx, userID) if err == sql.ErrNoRows { rueidisaside.OverrideCacheTTL(ctx, 30*time.Second) return "NOT_FOUND", nil // cached for 30 seconds } return user, nil // cached for 5 minutes }) ``` Closes #921
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lines changed

3 files changed

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‎rueidisaside/aside.go‎

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -163,6 +163,8 @@ retry:
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}
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if rueidis.IsRedisNil(err) { // successfully set client id on the key as a lock
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// attach TTL pointer to context for potential modification via OverrideCacheTTL
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ctx = context.WithValue(ctx, ttlKey, &ttl)
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if val, err = fn(ctx, key); err == nil {
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err = setkey.Exec(ctx, c.client, []string{key}, []string{id, val, strconv.FormatInt(ttl.Milliseconds(), 10)}).Error()
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}
@@ -222,6 +224,19 @@ func (c *Client) Close() {
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const PlaceholderPrefix = "rueidisid:"
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type ctxKey struct{}
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var ttlKey = ctxKey{}
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// OverrideCacheTTL sets a custom TTL for the cache entry being populated in the current context.
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// It can be called in the callback function passed to CacheAsideClient.Get() to customize
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// the TTL based on the data being cached.
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func OverrideCacheTTL(ctx context.Context, ttl time.Duration) {
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if p, ok := ctx.Value(ttlKey).(*time.Duration); ok {
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*p = ttl
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}
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}
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var (
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delkey = rueidis.NewLuaScript(`if redis.call("GET",KEYS[1]) == ARGV[1] then return redis.call("DEL",KEYS[1]) else return 0 end`)
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setkey = rueidis.NewLuaScript(`if redis.call("GET",KEYS[1]) == ARGV[1] then return redis.call("SET",KEYS[1],ARGV[2],"PX",ARGV[3]) else return 0 end`)

‎rueidisaside/aside_test.go‎

Lines changed: 104 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -512,3 +512,107 @@ func TestMultipleClientLL(t *testing.T) {
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}
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}
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}
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func TestOverrideCacheTTL(t *testing.T) {
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client := makeClient(t, addr)
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defer client.Close()
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key := strconv.Itoa(rand.Int())
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val, err := client.Get(context.Background(), time.Second*5, key, func(ctx context.Context, key string) (val string, err error) {
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OverrideCacheTTL(ctx, time.Millisecond*300)
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return "1", nil
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})
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if err != nil || val != "1" {
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t.Fatal(err)
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}
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val, err = client.Get(context.Background(), time.Second*5, key, nil)
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if err != nil || val != "1" {
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t.Fatal(err)
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}
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time.Sleep(time.Millisecond * 400)
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val, err = client.Get(context.Background(), time.Second*5, key, nil) // should miss
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if !rueidis.IsRedisNil(err) {
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t.Fatal("expected cache miss after overridden TTL expired")
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}
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}
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func TestOverrideCacheTTLLL(t *testing.T) {
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client := makeClientWithLuaLock(t, addr)
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defer client.Close()
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key := strconv.Itoa(rand.Int())
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val, err := client.Get(context.Background(), time.Second*5, key, func(ctx context.Context, key string) (val string, err error) {
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OverrideCacheTTL(ctx, time.Millisecond*300)
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return "1", nil
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})
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if err != nil || val != "1" {
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t.Fatal(err)
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}
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val, err = client.Get(context.Background(), time.Second*5, key, nil)
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if err != nil || val != "1" {
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t.Fatal(err)
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}
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time.Sleep(time.Millisecond * 400)
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val, err = client.Get(context.Background(), time.Second*5, key, nil) // should miss
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if !rueidis.IsRedisNil(err) {
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t.Fatal("expected cache miss after overridden TTL expired")
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}
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}
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func TestOverrideCacheTTLNegativeCaching(t *testing.T) {
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client := makeClient(t, addr)
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defer client.Close()
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key := strconv.Itoa(rand.Int())
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val, err := client.Get(context.Background(), time.Second*5, key, func(ctx context.Context, key string) (val string, err error) {
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OverrideCacheTTL(ctx, time.Millisecond*300)
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return "NOT_FOUND", nil
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})
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if err != nil || val != "NOT_FOUND" {
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t.Fatal(err)
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}
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val, err = client.Get(context.Background(), time.Second*5, key, nil)
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if err != nil || val != "NOT_FOUND" {
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t.Fatal(err)
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}
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time.Sleep(time.Millisecond * 400)
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val, err = client.Get(context.Background(), time.Second*5, key, func(ctx context.Context, key string) (val string, err error) {
586+
return "FOUND", nil
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})
588+
if err != nil || val != "FOUND" {
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t.Fatal(err)
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}
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}
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func TestOverrideCacheTTLNegativeCachingLL(t *testing.T) {
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client := makeClientWithLuaLock(t, addr)
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defer client.Close()
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key := strconv.Itoa(rand.Int())
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val, err := client.Get(context.Background(), time.Second*5, key, func(ctx context.Context, key string) (val string, err error) {
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OverrideCacheTTL(ctx, time.Millisecond*300)
600+
return "NOT_FOUND", nil
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})
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if err != nil || val != "NOT_FOUND" {
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t.Fatal(err)
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}
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val, err = client.Get(context.Background(), time.Second*5, key, nil)
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if err != nil || val != "NOT_FOUND" {
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t.Fatal(err)
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}
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time.Sleep(time.Millisecond * 400)
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val, err = client.Get(context.Background(), time.Second*5, key, func(ctx context.Context, key string) (val string, err error) {
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return "FOUND", nil
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})
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if err != nil || val != "FOUND" {
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t.Fatal(err)
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}
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}

‎rueidisaside/typed_aside_test.go‎

Lines changed: 54 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -163,3 +163,57 @@ func TestTypedCacheAsideClient_Del(t *testing.T) {
163163
t.Fatal("expected function to be called because the value should be deleted")
164164
}
165165
}
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func TestTypedCacheAsideClient_OverrideTTL(t *testing.T) {
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baseClient := makeClient(t, addr)
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t.Cleanup(baseClient.Close)
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serializer := func(v *testStruct) (string, error) {
172+
if v == nil {
173+
return "nilTestStruct", nil
174+
}
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b, err := json.Marshal(v)
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return string(b), err
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}
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deserializer := func(s string) (*testStruct, error) {
180+
if s == "nilTestStruct" {
181+
return nil, nil
182+
}
183+
var v testStruct
184+
err := json.Unmarshal([]byte(s), &v)
185+
return &v, err
186+
}
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client := NewTypedCacheAsideClient[testStruct](baseClient, serializer, deserializer)
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t.Run("override ttl for negative caching", func(t *testing.T) {
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key := randStr()
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val, err := client.Get(context.Background(), time.Second*5, key, func(ctx context.Context, key string) (*testStruct, error) {
194+
OverrideCacheTTL(ctx, time.Millisecond*300)
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return nil, nil
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})
197+
if err != nil || val != nil {
198+
t.Fatalf("expected nil value, got %v, err: %v", val, err)
199+
}
200+
201+
val, err = client.Get(context.Background(), time.Second*5, key, nil)
202+
if err != nil || val != nil {
203+
t.Fatalf("expected cached nil value, got %v, err: %v", val, err)
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}
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time.Sleep(time.Millisecond * 400)
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found := &testStruct{ID: 42, Name: "found"}
209+
val, err = client.Get(context.Background(), time.Second*5, key, func(ctx context.Context, key string) (*testStruct, error) {
210+
return found, nil
211+
})
212+
if err != nil {
213+
t.Fatal(err)
214+
}
215+
if val.ID != found.ID || val.Name != found.Name {
216+
t.Fatalf("expected %v, got %v", found, val)
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}
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})
219+
}

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