158ecc6235
Active discovery never produced cameras rows. Drop the scanner, systemd unit, ingest trigger, and docs/env knobs. Keep RTSP preview via ffmpeg.
72 lines
2.1 KiB
Python
72 lines
2.1 KiB
Python
"""Background ffmpeg — never block a FastAPI request on a frame grab.
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ffmpeg frame grabs are scheduled with asyncio.create_task and shared per URL.
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"""
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from __future__ import annotations
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import asyncio
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import shutil
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from cachetools import TTLCache
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_ffmpeg_cache: TTLCache = TTLCache(maxsize=100, ttl=300)
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_ffmpeg_tasks: dict[str, asyncio.Task] = {}
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_FFMPEG = shutil.which("ffmpeg")
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def cached_ffmpeg_jpeg(url: str) -> bytes | None:
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return _ffmpeg_cache.get(url)
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def schedule_ffmpeg_snapshot(url: str, timeout: float = 8.0) -> asyncio.Task:
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"""Start (or reuse) an ffmpeg JPEG grab. Caller may await the task."""
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existing = _ffmpeg_tasks.get(url)
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if existing is not None and not existing.done():
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return existing
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task = asyncio.create_task(_ffmpeg_grab_and_cache(url, timeout))
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_ffmpeg_tasks[url] = task
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return task
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async def _ffmpeg_grab(url: str, timeout: float = 8.0) -> bytes | None:
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"""Grab one JPEG frame. Isolated so tests can stub it."""
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if not _FFMPEG or not url.lower().startswith("rtsp://"):
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return None
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cmd = [
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_FFMPEG, "-hide_banner", "-loglevel", "error", "-nostdin",
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"-rtsp_transport", "tcp",
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"-timeout", "4000000",
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"-i", url,
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"-frames:v", "1",
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"-f", "image2pipe", "-vcodec", "mjpeg",
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"pipe:1",
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]
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try:
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proc = await asyncio.create_subprocess_exec(
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*cmd,
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stdout=asyncio.subprocess.PIPE,
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stderr=asyncio.subprocess.DEVNULL,
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)
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except FileNotFoundError:
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return None
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try:
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stdout, _ = await asyncio.wait_for(proc.communicate(), timeout=timeout)
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except asyncio.TimeoutError:
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proc.kill()
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try:
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await proc.wait()
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except Exception: # noqa: BLE001
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pass
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return None
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if proc.returncode not in (0, None) or not stdout or len(stdout) < 64:
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return None
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if stdout[:2] != b"\xff\xd8":
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return None
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return stdout
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async def _ffmpeg_grab_and_cache(url: str, timeout: float) -> bytes | None:
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data = await _ffmpeg_grab(url, timeout)
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if data:
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_ffmpeg_cache[url] = data
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return data
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