update monitored hardware after a runtime config swap

`swap_runtime_config` rebound the stats emitter to the new config but not its `HardwareStats`, which kept polling hardware for the old config and applied camera updates to the discarded object. It now follows the swap along with its camera update subscriber.

frigate/api/config_util.py

@@ -51,6 +51,7 @@ def swap_runtime_config(app: FastAPI, config: FrigateConfig) -> None:
 
     if app.stats_emitter is not None:
         app.stats_emitter.config = config
+        app.stats_emitter.hardware_stats.set_config(config)
 
     if app.dispatcher is not None:
         app.dispatcher.config = config

frigate/stats/hardware.py

@@ -256,6 +256,17 @@ class HardwareStats:
         )
         self.update_config()
 
+    def set_config(self, config: FrigateConfig) -> None:
+        """Follow a runtime config swap and recalculate the monitored hardware.
+
+        The camera update subscriber has to follow too, or later camera updates
+        would land on the discarded config.
+        """
+        self.config = config
+        self._config_subscriber.config = config
+        self._config_subscriber.camera_configs = config.cameras
+        self.update_config()
+
     def update_config(self) -> None:
         """Recalculate all hardware that needs to be monitored from the config."""
         names = self._scan_ffmpeg() | self._scan_detectors() | self._scan_enrichments()

frigate/test/test_config_util.py

@@ -26,6 +26,7 @@ class TestSwapRuntimeConfig(unittest.TestCase):
         app.genai_manager.update_config.assert_called_once_with(config)
         app.profile_manager.update_config.assert_called_once_with(config)
         self.assertIs(app.stats_emitter.config, config)
+        app.stats_emitter.hardware_stats.set_config.assert_called_once_with(config)
         self.assertIs(app.dispatcher.config, config)
         for comm in app.dispatcher.comms:
             self.assertIs(comm.config, config)

frigate/test/test_hardware_stats.py

@@ -288,6 +288,17 @@ class TestUpdateConfig(HardwareStatsTestCase):
 
         self.assertEqual(set(stats._monitored), {"rockchip"})
 
+    def test_follows_a_runtime_config_swap(self):
+        stats = self.make_stats(self.make_config())
+        self.assertEqual(set(stats._monitored), set())
+
+        swapped = self.make_config("preset-rk-h264")
+        stats.set_config(swapped)
+
+        self.assertEqual(set(stats._monitored), {"rockchip"})
+        self.assertIs(self.subscriber.return_value.config, swapped)
+        self.assertIs(self.subscriber.return_value.camera_configs, swapped.cameras)
+
 
 class TestUpdateStats(HardwareStatsTestCase):
     def run_stats(self, stats: HardwareStats) -> dict: