add snapshot test for go2rtc pid after restart

frigate/stats/util.py

@@ -236,6 +236,15 @@ def skipped_percent(skipped_fps: float, camera_fps: float, enabled: bool) -> flo
     return round(skipped_fps / camera_fps * 100, 1)
 
 
+def get_go2rtc_pid(cpu_usages: dict[str, dict[str, Any]]) -> int | None:
+    """Find the pid of the running go2rtc process in the cpu usages."""
+    for pid, usage in cpu_usages.items():
+        if usage.get("cmdline", "").split(" ")[0].endswith("/go2rtc"):
+            return int(pid)
+
+    return None
+
+
 def stats_snapshot(
     config: FrigateConfig,
     stats_tracking: StatsTrackingTypes,
@@ -356,6 +365,14 @@ def stats_snapshot(
 
     stats["service"]["storage"]["/dev/shm"] = calculate_shm_requirements(config)
 
+    cpu_usages = stats.get("cpu_usages", {})
+
+    # go2rtc is supervised by s6, so its pid changes when s6 restarts it
+    go2rtc_pid = get_go2rtc_pid(cpu_usages)
+
+    if go2rtc_pid is not None:
+        stats_tracking["processes"]["go2rtc"] = go2rtc_pid
+
     stats["processes"] = {}
     for name, pid in stats_tracking["processes"].items():
         stats["processes"][name] = {
@@ -364,7 +381,6 @@ def stats_snapshot(
 
     # Embed cpu/mem stats into detectors, cameras, and processes
     # so history consumers don't need the full cpu_usages dict
-    cpu_usages = stats.get("cpu_usages", {})
 
     for det_stats in stats["detectors"].values():
         pid_str = str(det_stats.get("pid", ""))

frigate/test/test_go2rtc_pid_stats.py

@@ -0,0 +1,70 @@
+"""Tests for resolving the go2rtc pid from cpu usages."""
+
+import unittest
+from types import SimpleNamespace
+from unittest.mock import Mock, patch
+
+from frigate.stats.util import get_go2rtc_pid, stats_snapshot
+
+
+class TestGo2rtcPid(unittest.TestCase):
+    def test_finds_go2rtc_by_binary_path(self):
+        cpu_usages = {
+            "frigate.full_system": {"cpu": "1.0", "mem": "2.0"},
+            "100": {"cmdline": "ffmpeg -i rtsp://127.0.0.1:8554/go2rtc_cam"},
+            "200": {
+                "cmdline": "/usr/local/go2rtc/bin/go2rtc -config=/dev/shm/go2rtc.yaml"
+            },
+            "300": {"cmdline": "frigate.recording"},
+        }
+
+        self.assertEqual(get_go2rtc_pid(cpu_usages), 200)
+
+    def test_finds_custom_go2rtc_binary(self):
+        self.assertEqual(get_go2rtc_pid({"42": {"cmdline": "/config/go2rtc"}}), 42)
+
+    def test_returns_none_when_go2rtc_is_not_running(self):
+        self.assertIsNone(get_go2rtc_pid({"100": {"cmdline": "ffmpeg -i x"}}))
+        self.assertIsNone(get_go2rtc_pid({}))
+
+
+class TestGo2rtcPidInSnapshot(unittest.TestCase):
+    def snapshot(self, tracking: dict, go2rtc_pid: int) -> dict:
+        def update_stats(stats: dict) -> None:
+            stats["cpu_usages"] = {
+                str(go2rtc_pid): {
+                    "cmdline": "/usr/local/go2rtc/bin/go2rtc -config=x",
+                    "cpu": str(go2rtc_pid / 100),
+                    "mem": str(go2rtc_pid / 10),
+                }
+            }
+
+        config = SimpleNamespace(
+            cameras={},
+            telemetry=SimpleNamespace(stats=SimpleNamespace(network_bandwidth=False)),
+        )
+        hardware_stats = Mock()
+        hardware_stats.update_stats.side_effect = update_stats
+
+        with (
+            patch("frigate.stats.util.get_detector_stats", return_value={}),
+            patch("frigate.stats.util.embeddings_stats", return_value={}),
+            patch("frigate.stats.util.calculate_shm_requirements", return_value={}),
+        ):
+            return stats_snapshot(config, tracking, hardware_stats)
+
+    def test_snapshot_follows_go2rtc_restart(self):
+        tracking = {
+            "camera_metrics": {},
+            "detectors": {},
+            "started": 0,
+            "latest_frigate_version": "",
+            "processes": {"go2rtc": 200, "recording": 50},
+            "storage_maintainer": None,
+        }
+
+        first = self.snapshot(tracking, 200)["processes"]["go2rtc"]
+        self.assertEqual(first, {"pid": 200, "cpu": "2.0", "mem": "20.0"})
+
+        restarted = self.snapshot(tracking, 300)["processes"]["go2rtc"]
+        self.assertEqual(restarted, {"pid": 300, "cpu": "3.0", "mem": "30.0"})