Leo Vasanko
6de9b443ae
- Use ffmpeg CLI directly for HEIC/HEIF previews (bypassing pyvips which cannot encode >8-bit AVIF on current system). ffmpeg handles tile assembly, EXIF rotation, HDR metadata and ICC profiles automatically. - pyvips remains primary for other image formats; ffmpeg is fallback. - Simplify _get_image_dimensions() to use pyvips header read for all formats including HEIC, with ffprobe as fallback. - Move all imports to top of preview.py; remove lazy OnlyOffice import. - Worker pool: add readiness handshake (\x01 byte), bounded idle wait with PREVIEW_TIMEOUT, eager module import before signalling. - Fix dispatch data check bug (was 'if data is not None' -> 'if data'). - Add logger.exception for unhandled preview/dispatch errors. - EmojiFormatter now includes tracebacks for exception logs. - Return 503 on preview timeouts instead of 504.
150 lines
4.3 KiB
Python
150 lines
4.3 KiB
Python
"""Preview generation worker subprocess.
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Two modes are supported:
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1) Legacy one-shot mode: argv has path/quality/maxsize/maxzoom.
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2) Long-lived mode: read framed requests from stdin and write framed responses.
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Framed request format (stdin):
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(uint32 json size)(uint32 data size)(json)(binary data)
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Framed response format (stdout):
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(blake3(packet))(uint32 json size)(uint32 payload size)(json)(binary payload)
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where packet = (uint32 json size)(uint32 payload size)(json)(binary payload).
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"""
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import contextlib
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import io
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import logging
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import struct
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import sys
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from pathlib import Path
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import msgspec
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from blake3 import blake3
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class PreviewRequest(msgspec.Struct, omit_defaults=True):
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path: str
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quality: int
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maxsize: int
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maxzoom: float
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class PreviewResponse(msgspec.Struct, omit_defaults=True):
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ok: bool
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mime: str | None = None
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backend: str | None = None
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timings: list[float] | None = None
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error: str | None = None
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stderr: str | None = None
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_enc = msgspec.json.Encoder()
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_dec_req = msgspec.json.Decoder(PreviewRequest)
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def _read_exactly(f, n: int) -> bytes:
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buf = b""
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while len(buf) < n:
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chunk = f.read(n - len(buf))
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if not chunk:
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raise EOFError
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buf += chunk
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return buf
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def _read_request() -> tuple[PreviewRequest, bytes] | None:
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try:
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header = _read_exactly(sys.stdin.buffer, 8)
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except EOFError:
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return None
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json_size, data_size = struct.unpack("<II", header)
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meta_raw = _read_exactly(sys.stdin.buffer, json_size)
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data = b""
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if data_size:
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data = _read_exactly(sys.stdin.buffer, data_size)
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req = _dec_req.decode(meta_raw)
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return req, data
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def _write_response(resp: PreviewResponse, payload: bytes) -> None:
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meta_bytes = _enc.encode(resp)
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packet = struct.pack("<II", len(meta_bytes), len(payload)) + meta_bytes + payload
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checksum = blake3(packet).digest()
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sys.stdout.buffer.write(checksum)
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sys.stdout.buffer.write(packet)
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sys.stdout.buffer.flush()
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def _run_once() -> None:
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if len(sys.argv) != 5:
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sys.stderr.write(f"Usage: {sys.argv[0]} <path> <quality> <maxsize> <maxzoom>\n")
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sys.exit(1)
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from cista.preview import dispatch
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path = Path(sys.argv[1])
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quality = int(sys.argv[2])
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maxsize = int(sys.argv[3])
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maxzoom = float(sys.argv[4])
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result, _ = dispatch(path, quality, maxsize, maxzoom)
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if result:
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sys.stdout.buffer.write(result)
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sys.stdout.buffer.flush()
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def _run_loop() -> None:
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from cista.preview import dispatch
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while True:
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result = _read_request()
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if result is None:
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return
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req, data = result
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stderr_capture = io.StringIO()
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handler = logging.StreamHandler(stderr_capture)
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root_logger = logging.getLogger()
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root_logger.addHandler(handler)
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try:
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with contextlib.redirect_stderr(stderr_capture):
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result, resp = dispatch(
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Path(req.path), req.quality, req.maxsize, req.maxzoom, data
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)
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if not resp.ok:
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captured = stderr_capture.getvalue().strip()
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if captured:
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resp = PreviewResponse(
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ok=False,
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backend=resp.backend,
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error=resp.error,
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stderr=captured,
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)
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_write_response(resp, result or b"")
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except Exception as e:
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logging.exception("Preview worker error for %s", req.path)
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captured = stderr_capture.getvalue().strip()
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_write_response(
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PreviewResponse(ok=False, error=str(e), stderr=captured or None), b""
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)
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finally:
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root_logger.removeHandler(handler)
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handler.close()
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def main() -> None:
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# Configure all log output to stderr before any imports that may emit logs.
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logging.basicConfig(stream=sys.stderr, level=logging.INFO)
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if len(sys.argv) > 1:
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_run_once()
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return
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# Eagerly import heavy modules before signalling readiness so the parent
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# does not hand us a request while we are still initialising.
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from cista.preview import dispatch # noqa: F401
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sys.stdout.buffer.write(b"\x01")
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sys.stdout.buffer.flush()
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_run_loop()
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if __name__ == "__main__":
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main()
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