frigate: clean up process cmdlines in cpu stats

The process cmdline gets read from /proc/pid/cmdline which is a memory
allocation with a rounded up size. The psutil library looks for a
Null-terminated string, but apparently not all cmdlines have that.

pkgs/by-name/fr/frigate/package.nix

@@ -98,6 +98,8 @@ python3Packages.buildPythonApplication rec {
     })
     # https://github.com/microsoft/onnxruntime/issues/26717
     ./onnxruntime-compat.patch
+    # https://github.com/blakeblackshear/frigate/pull/22089
+    ./proc-cmdline-strip.patch
   ];
 
   postPatch = ''

pkgs/by-name/fr/frigate/proc-cmdline-strip.patch

@@ -0,0 +1,27 @@
+Strip trailing whitespace from process commandlines. This is annoying for exact
+process matches against Prometheus labels.
+
+https://github.com/blakeblackshear/frigate/pull/22089
+
+diff --git a/frigate/util/services.py b/frigate/util/services.py
+index b31a7eea3..f1e8f0f5f 100644
+--- a/frigate/util/services.py
++++ b/frigate/util/services.py
+@@ -118,7 +118,7 @@ def get_cpu_stats() -> dict[str, dict]:
+         pid = str(process.info["pid"])
+         try:
+             cpu_percent = process.info["cpu_percent"]
+-            cmdline = process.info["cmdline"]
++            cmdline = " ".join(process.info["cmdline"]).rstrip()
+ 
+             with open(f"/proc/{pid}/stat", "r") as f:
+                 stats = f.readline().split()
+@@ -152,7 +152,7 @@ def get_cpu_stats() -> dict[str, dict]:
+                 "cpu": str(cpu_percent),
+                 "cpu_average": str(round(cpu_average_usage, 2)),
+                 "mem": f"{mem_pct}",
+-                "cmdline": clean_camera_user_pass(" ".join(cmdline)),
++                "cmdline": clean_camera_user_pass(cmdline),
+             }
+         except Exception:
+             continue