[ADDED] ListKeysFiltered form listing KV keys with multiple filters (#…

…1711)

Co-authored-by: somratdutta <duttasomratand.com>

jetstream/kv.go

@@ -178,6 +178,9 @@ type (
 		// the key value store in a streaming fashion (on a channel).
 		ListKeys(ctx context.Context, opts ...WatchOpt) (KeyLister, error)
 
+		// ListKeysFiltered ListKeysWithFilters returns a KeyLister for filtered keys in the bucket.
+		ListKeysFiltered(ctx context.Context, filters ...string) (KeyLister, error)
+
 		// History will return all historical values for the key (up to
 		// KeyValueMaxHistory).
 		History(ctx context.Context, key string, opts ...WatchOpt) ([]KeyValueEntry, error)
@@ -1271,6 +1274,36 @@ func (kv *kvs) ListKeys(ctx context.Context, opts ...WatchOpt) (KeyLister, error
 	return kl, nil
 }
 
+// ListKeysWithFilters returns a channel of keys matching the provided filters using WatchFiltered.
+func (kv *kvs) ListKeysFiltered(ctx context.Context, filters ...string) (KeyLister, error) {
+	watcher, err := kv.WatchFiltered(ctx, filters)
+	if err != nil {
+		return nil, err
+	}
+
+	// Reuse the existing keyLister implementation
+	kl := &keyLister{watcher: watcher, keys: make(chan string, 256)}
+
+	go func() {
+		defer close(kl.keys)
+		defer watcher.Stop()
+
+		for {
+			select {
+			case entry := <-watcher.Updates():
+				if entry == nil { // Indicates all initial values are received
+					return
+				}
+				kl.keys <- entry.Key()
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+
+	return kl, nil
+}
+
 func (kl *keyLister) Keys() <-chan string {
 	return kl.keys
 }

jetstream/test/kv_test.go

@@ -1037,6 +1037,68 @@ func TestKeyValueListKeys(t *testing.T) {
 	}
 }
 
+func TestListKeysFiltered(t *testing.T) {
+	s := RunBasicJetStreamServer()
+	defer shutdownJSServerAndRemoveStorage(t, s)
+
+	nc, js := jsClient(t, s)
+	defer nc.Close()
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	// Create Key-Value store.
+	kv, err := js.CreateKeyValue(ctx, jetstream.KeyValueConfig{Bucket: "KVS", History: 2})
+	expectOk(t, err)
+
+	// Helper function to add key-value pairs.
+	putKeys := func(data map[string]string) {
+		for key, value := range data {
+			t.Helper()
+			_, err := kv.Put(ctx, key, []byte(value))
+			expectOk(t, err)
+		}
+	}
+
+	// Add key-value pairs.
+	putKeys(map[string]string{
+		"apple":  "fruit",
+		"banana": "fruit",
+		"carrot": "vegetable",
+	})
+
+	// Use filters to list keys matching "apple".
+	filters := []string{"apple"}
+	keyLister, err := kv.ListKeysFiltered(ctx, filters...)
+	expectOk(t, err)
+
+	// Collect filtered keys from KeyLister
+	var filteredKeys []string
+	for key := range keyLister.Keys() {
+		filteredKeys = append(filteredKeys, key)
+	}
+
+	// Validate expected keys.
+	expectedKeys := []string{"apple"}
+	if len(filteredKeys) != len(expectedKeys) {
+		t.Fatalf("Expected %d filtered key(s), got %d", len(expectedKeys), len(filteredKeys))
+	}
+
+	for _, key := range expectedKeys {
+		if !contains(filteredKeys, key) {
+			t.Fatalf("Expected key %s in filtered keys, but not found", key)
+		}
+	}
+}
+
+func contains(slice []string, key string) bool {
+	for _, k := range slice {
+		if k == key {
+			return true
+		}
+	}
+	return false
+}
+
 func TestKeyValueCrossAccounts(t *testing.T) {
 	conf := createConfFile(t, []byte(`
 		listen: 127.0.0.1:-1