backend: Change COMPLETE message error to info

COMPLETE messages are not critical for functionality since the client
will continue to receive updates even if the COMPLETE message fails.
Changed the log level to reduce noise in error logs while maintaining
visibility through info logs.

Signed-off-by: Kautilya Tripathi <[email protected]>

backend/cmd/multiplexer.go

@@ -583,7 +583,6 @@ func (m *Multiplexer) sendIfNewResourceVersion(
 // sendCompleteMessage sends a COMPLETE message to the client.
 func (m *Multiplexer) sendCompleteMessage(conn *Connection, clientConn *websocket.Conn) error {
 	conn.mu.RLock()
-
 	if conn.closed {
 		conn.mu.RUnlock()
 		return nil // Connection is already closed, no need to send message
@@ -602,9 +601,11 @@ func (m *Multiplexer) sendCompleteMessage(conn *Connection, clientConn *websocke
 	conn.writeMu.Lock()
 	defer conn.writeMu.Unlock()
 
-	if err := clientConn.WriteJSON(completeMsg); err != nil {
-		logger.Log(logger.LevelError, nil, err, "writing complete message")
-		return err
+	err := clientConn.WriteJSON(completeMsg)
+	if err != nil {
+		logger.Log(logger.LevelInfo, nil, err, "connection closed while writing complete message")
+
+		return nil // Just return nil for any error - connection is dead anyway
 	}
 
 	return nil

backend/cmd/multiplexer_test.go

@@ -1001,7 +1001,67 @@ func TestSendCompleteMessage_ClosedConnection(t *testing.T) {
 	// Test with closed connection
 	clientConn.Close()
 	err = m.sendCompleteMessage(conn, clientConn)
-	assert.Error(t, err)
+	assert.NoError(t, err)
+}
+
+func TestSendCompleteMessage_ErrorConditions(t *testing.T) {
+	tests := []struct {
+		name          string
+		setupConn     func(*Connection, *websocket.Conn)
+		expectedError bool
+	}{
+		{
+			name: "connection already marked as closed",
+			setupConn: func(conn *Connection, _ *websocket.Conn) {
+				conn.closed = true
+			},
+			expectedError: false,
+		},
+		{
+			name: "normal closure",
+			setupConn: func(_ *Connection, clientConn *websocket.Conn) {
+				//nolint:errcheck
+				clientConn.WriteMessage(websocket.CloseMessage,
+					websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
+				clientConn.Close()
+			},
+			expectedError: false,
+		},
+		{
+			name: "unexpected close error",
+			setupConn: func(_ *Connection, clientConn *websocket.Conn) {
+				//nolint:errcheck
+				clientConn.WriteMessage(websocket.CloseMessage,
+					websocket.FormatCloseMessage(websocket.CloseProtocolError, ""))
+				clientConn.Close()
+			},
+			expectedError: false, // All errors return nil now
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			m := NewMultiplexer(kubeconfig.NewContextStore())
+			clientConn, clientServer := createTestWebSocketConnection()
+			defer clientServer.Close()
+
+			conn := &Connection{
+				ClusterID: "test-cluster",
+				Path:      "/api/v1/pods",
+				UserID:    "test-user",
+				Query:     "watch=true",
+			}
+
+			tt.setupConn(conn, clientConn)
+			err := m.sendCompleteMessage(conn, clientConn)
+
+			if tt.expectedError {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+			}
+		})
+	}
 }
 
 func createMockKubeAPIServer() *httptest.Server {