fix(bridge): camera process-race and unhandled JSON errors in two handlers

Found during a targeted code review, not from a user report:

- _run_jpeg_loop()/_run_h264_loop() operated directly on the shared
  self._proc_jpeg/self._proc_h264 instance attributes in their cleanup,
  unlike _run_mjpeg_loop() (already fixed for exactly this) which uses a
  local `proc` reference. If a loop's task is cancelled - e.g. by
  CameraCache.reset() after the printer rotates its stream URL on reboot -
  while a new task has already started and assigned its own process to the
  shared attribute, the cancelled task's cleanup killed the NEWER process
  instead of its own, leaking its own ffmpeg child as an orphan. Applied
  the same local-variable + identity-check pattern already used by
  _run_mjpeg_loop.

- handle_api_settings_post and handle_api_update_apply were the only two
  of ~84 handlers that called `await request.json()` without a try/except -
  every other handler follows the established pattern of returning a clean
  400 for a malformed body. A trivial malformed request to either endpoint
  produced an unhandled 500 with a full traceback instead.

New tests in tests/test_camera_process_race.py,
tests/test_settings.py, and tests/test_update_check.py cover both.
This commit is contained in:
2026-08-04 15:31:36 +02:00
parent ce71299896
commit 5eeed97514
4 changed files with 159 additions and 38 deletions

View File

@ -713,7 +713,7 @@ class CameraCache:
await asyncio.sleep(2.0)
continue
try:
self._proc_jpeg = await asyncio.create_subprocess_exec(
proc = await asyncio.create_subprocess_exec(
_find_ffmpeg(), "-loglevel", "warning",
*self._input_args(url), "-i", url,
"-vf", "fps=2",
@ -722,6 +722,7 @@ class CameraCache:
stdout=asyncio.subprocess.PIPE,
stderr=asyncio.subprocess.PIPE,
)
self._proc_jpeg = proc
except Exception as e:
log.warning(f"CameraCache: ffmpeg-jpeg start failed: {e}")
await asyncio.sleep(3.0)
@ -731,7 +732,7 @@ class CameraCache:
rc = None
try:
while True:
chunk = await self._proc_jpeg.stdout.read(self.TS_CHUNK)
chunk = await proc.stdout.read(self.TS_CHUNK)
if not chunk:
break
buf += chunk
@ -751,26 +752,31 @@ class CameraCache:
except Exception as e:
log.debug(f"CameraCache: jpeg-loop unterbrochen: {e}")
finally:
# Kill + wait - otherwise the child process lingers as a zombie and
# asyncio reports "Unknown child pid ..." on the next reaper tick.
if self._proc_jpeg is not None:
# NOTE: cleanup operates on the local `proc` reference, not on
# self._proc_jpeg - see _run_mjpeg_loop's identical comment.
# If this task got cancelled (e.g. by reset()), a new task may
# already have started and assigned its own process to
# self._proc_jpeg by the time we reach here; killing that
# shared attribute instead of our own local proc would kill
# the WRONG (newer) process and leak this one as an orphan.
try:
proc.kill()
except Exception:
pass
try:
await proc.wait()
except Exception:
pass
rc = proc.returncode
if rc:
try:
self._proc_jpeg.kill()
err = await proc.stderr.read(500)
if err:
log.warning(f"CameraCache: ffmpeg-jpeg stderr: {err.decode(errors='replace').strip()}")
except Exception:
pass
try:
await self._proc_jpeg.wait()
except Exception:
pass
rc = self._proc_jpeg.returncode
if rc:
try:
err = await self._proc_jpeg.stderr.read(500)
if err:
log.warning(f"CameraCache: ffmpeg-jpeg stderr: {err.decode(errors='replace').strip()}")
except Exception:
pass
self._proc_jpeg = None
if self._proc_jpeg is proc:
self._proc_jpeg = None
if rc:
self._fail_count_jpeg += 1
delay = min(2.0 * (2 ** self._fail_count_jpeg), 300.0)
@ -788,7 +794,7 @@ class CameraCache:
await asyncio.sleep(2.0)
continue
try:
self._proc_h264 = await asyncio.create_subprocess_exec(
proc = await asyncio.create_subprocess_exec(
_find_ffmpeg(), "-loglevel", "warning",
*self._input_args(url), "-i", url,
"-c:v", "copy", "-an",
@ -796,6 +802,7 @@ class CameraCache:
stdout=asyncio.subprocess.PIPE,
stderr=asyncio.subprocess.PIPE,
)
self._proc_h264 = proc
except Exception as e:
log.warning(f"CameraCache: ffmpeg-h264 start failed: {e}")
await asyncio.sleep(3.0)
@ -804,7 +811,7 @@ class CameraCache:
rc = None
try:
while True:
chunk = await self._proc_h264.stdout.read(self.TS_CHUNK)
chunk = await proc.stdout.read(self.TS_CHUNK)
if not chunk:
break
# Fanout: non-blocking per subscriber; slow clients
@ -822,24 +829,31 @@ class CameraCache:
except Exception as e:
log.debug(f"CameraCache: h264-loop unterbrochen: {e}")
finally:
if self._proc_h264 is not None:
# NOTE: cleanup operates on the local `proc` reference, not on
# self._proc_h264 - see _run_mjpeg_loop's identical comment.
# If this task got cancelled (e.g. by reset()), a new task may
# already have started and assigned its own process to
# self._proc_h264 by the time we reach here; killing that
# shared attribute instead of our own local proc would kill
# the WRONG (newer) process and leak this one as an orphan.
try:
proc.kill()
except Exception:
pass
try:
await proc.wait()
except Exception:
pass
rc = proc.returncode
if rc:
try:
self._proc_h264.kill()
err = await proc.stderr.read(500)
if err:
log.warning(f"CameraCache: ffmpeg-h264 stderr: {err.decode(errors='replace').strip()}")
except Exception:
pass
try:
await self._proc_h264.wait()
except Exception:
pass
rc = self._proc_h264.returncode
if rc:
try:
err = await self._proc_h264.stderr.read(500)
if err:
log.warning(f"CameraCache: ffmpeg-h264 stderr: {err.decode(errors='replace').strip()}")
except Exception:
pass
self._proc_h264 = None
if self._proc_h264 is proc:
self._proc_h264 = None
if rc:
self._fail_count_h264 += 1
delay = min(2.0 * (2 ** self._fail_count_h264), 300.0)
@ -5093,7 +5107,10 @@ class KobraXBridge:
async def handle_api_settings_post(self, request):
import configparser
data = await request.json()
try:
data = await request.json()
except Exception:
return self._json_cors({"error": "invalid json"}, status=400)
config_path = self._find_config_path()
config_path.parent.mkdir(parents=True, exist_ok=True)
@ -5513,7 +5530,10 @@ class KobraXBridge:
]
async def handle_api_update_apply(self, request):
data = await request.json()
try:
data = await request.json()
except Exception:
return web.json_response({"error": "invalid json"}, status=400)
new_tag = data.get("tag", "")
if "nightly" in self._read_version():
return web.json_response(