fix: improve memory pressure from getlogs

internal/api/backresthandler.go

@@ -504,54 +504,66 @@ func (s *BackrestHandler) GetLogs(ctx context.Context, req *connect.Request[v1.L
 		r.Close()
 	}()
 
-	var bufferMu sync.Mutex
-	var buffer bytes.Buffer
 	var errChan = make(chan error, 1)
+	var sendChan = make(chan []byte, 1)
+	var buffer bytes.Buffer
+	var bufferMu sync.Mutex
+
 	go func() {
 		data := make([]byte, 4*1024)
 		for {
 			n, err := r.Read(data)
 			if n == 0 {
-				close(errChan)
 				break
 			} else if err != nil && err != io.EOF {
 				errChan <- fmt.Errorf("failed to read log data: %w", err)
 				close(errChan)
-				return
+				break
 			}
 			bufferMu.Lock()
 			buffer.Write(data[:n])
+			if buffer.Len() > 128*1024 {
+				sendChan <- bytes.Clone(buffer.Bytes())
+				buffer.Reset()
+			}
 			bufferMu.Unlock()
 		}
+
+		if buffer.Len() > 0 {
+			bufferMu.Lock()
+			sendChan <- bytes.Clone(buffer.Bytes())
+			buffer.Reset()
+			bufferMu.Unlock()
+		}
+		close(sendChan)
 	}()
 
 	ticker := time.NewTicker(100 * time.Millisecond)
 	defer ticker.Stop()
 
-	flush := func() error {
-		bufferMu.Lock()
-		if buffer.Len() > 0 {
-			if err := resp.Send(&types.BytesValue{Value: buffer.Bytes()}); err != nil {
-				bufferMu.Unlock()
-				return fmt.Errorf("failed to send log data: %w", err)
-			}
-			buffer.Reset()
-		}
-		bufferMu.Unlock()
-		return nil
-	}
-
 	for {
 		select {
 		case <-ctx.Done():
-			return flush()
-		case err := <-errChan:
-			_ = flush()
-			return err
-		case <-ticker.C:
-			if err := flush(); err != nil {
+			return nil
+		case data, ok := <-sendChan:
+			if !ok {
+				return nil
+			}
+			if err := resp.Send(&types.BytesValue{Value: data}); err != nil {
 				return err
 			}
+		case err := <-errChan:
+			return err
+		case <-ticker.C:
+			bufferMu.Lock()
+			if buffer.Len() > 0 {
+				if err := resp.Send(&types.BytesValue{Value: bytes.Clone(buffer.Bytes())}); err != nil {
+					bufferMu.Unlock()
+					return err
+				}
+				buffer.Reset()
+			}
+			bufferMu.Unlock()
 		}
 	}