77 lines
2.5 KiB
Python
77 lines
2.5 KiB
Python
"""generate_thumbnail task: PIL/ffmpeg thumbnail generation on the thumbnail queue.
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Lives separately from import_file because thumbnails can be regenerated en
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masse (FC-2c adds the 'regenerate all' admin action) and they're CPU-bound
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so they deserve their own queue lane.
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"""
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from pathlib import Path
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from sqlalchemy.exc import DBAPIError, OperationalError
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from ..celery_app import celery
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from ..models import ImageRecord
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from ..services.importer import is_video
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from ..services.thumbnailer import Thumbnailer
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from ._sync_engine import sync_session_factory as _sync_session_factory
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IMAGES_ROOT = Path("/images")
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THUMB_MAGIC_JPEG = b"\xff\xd8\xff"
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THUMB_MAGIC_PNG = b"\x89PNG\r\n\x1a\n"
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def _thumb_is_valid(path: Path) -> bool:
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"""Return True iff `path` exists and starts with a JPEG or PNG magic header.
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The on-disk thumbnail format is set by services/thumbnailer.py — JPEG for
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opaque sources, PNG for alpha sources. Anything else (missing file, OSError,
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truncated, wrong magic) is invalid.
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"""
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try:
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with path.open("rb") as f:
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head = f.read(12)
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except OSError:
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return False
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if len(head) < 8:
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return False
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if head[:3] == THUMB_MAGIC_JPEG:
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return True
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if head[:8] == THUMB_MAGIC_PNG:
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return True
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return False
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@celery.task(
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name="backend.app.tasks.thumbnail.generate_thumbnail",
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bind=True,
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autoretry_for=(OperationalError, DBAPIError, OSError),
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retry_backoff=5,
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retry_backoff_max=60,
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retry_jitter=True,
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max_retries=3,
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soft_time_limit=120,
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time_limit=180,
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)
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def generate_thumbnail(self, image_id: int) -> dict:
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SessionLocal = _sync_session_factory()
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with SessionLocal() as session:
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record = session.get(ImageRecord, image_id)
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if record is None:
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return {"status": "missing", "image_id": image_id}
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thumbnailer = Thumbnailer(images_root=IMAGES_ROOT)
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source = Path(record.path)
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try:
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if is_video(source):
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result = thumbnailer.generate_video_thumbnail(source, record.sha256)
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else:
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result = thumbnailer.generate_image_thumbnail(source, record.sha256)
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except Exception as exc: # pragma: no cover — thumbnail failure is non-fatal
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return {"status": "failed", "image_id": image_id, "error": f"{type(exc).__name__}: {exc}"}
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record.thumbnail_path = str(result.path)
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session.add(record)
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session.commit()
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return {"status": "ok", "image_id": image_id, "path": str(result.path)}
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