Files
Ahmed Elshahat f0db3d7d14 fix(spiders): use os.replace for atomic checkpoint/cache writes on Windows
CheckpointManager.save() and ResponseCacheManager.put() write to a temp
file and then move it into place with Path.rename(). On Windows, os.rename
cannot overwrite an existing destination and raises FileExistsError
(WinError 183), so every write after the first one fails: checkpoint
saving raises and breaks resume, while the development response cache
swallows the error and keeps returning the stale entry.

Path.replace() (os.replace) overwrites the destination atomically on every
platform and behaves identically to rename() on POSIX, so this is a no-op
on Linux and macOS and only fixes the broken overwrite on Windows.

Add a regression test for the cache overwrite path; the checkpoint
overwrite is already covered by test_multiple_saves_overwrite.
2026-06-07 04:24:12 +03:00

91 lines
3.1 KiB
Python

import pickle
from pathlib import Path
from dataclasses import dataclass, field
import anyio
from anyio import Path as AsyncPath
from scrapling.core.utils import log
from scrapling.core._types import Set, List, Optional, TYPE_CHECKING
if TYPE_CHECKING:
from scrapling.spiders.request import Request
@dataclass
class CheckpointData:
"""Container for checkpoint state."""
requests: List["Request"] = field(default_factory=list)
seen: Set[bytes] = field(default_factory=set)
class CheckpointManager:
"""Manages saving and loading checkpoint state to/from disk."""
CHECKPOINT_FILE = "checkpoint.pkl"
def __init__(self, crawldir: str | Path | AsyncPath, interval: float = 300.0):
self.crawldir = AsyncPath(crawldir)
self._checkpoint_path = self.crawldir / self.CHECKPOINT_FILE
self.interval = interval
if not isinstance(interval, (int, float)):
raise TypeError("Checkpoints interval must be integer or float.")
else:
if interval < 0:
raise ValueError("Checkpoints interval must be equal or greater than 0.")
async def has_checkpoint(self) -> bool:
"""Check if a checkpoint exists."""
return await self._checkpoint_path.exists()
async def save(self, data: CheckpointData) -> None:
"""Save checkpoint data to disk atomically."""
await self.crawldir.mkdir(parents=True, exist_ok=True)
temp_path = self._checkpoint_path.with_suffix(".tmp")
try:
serialized = pickle.dumps(data, protocol=pickle.HIGHEST_PROTOCOL)
async with await anyio.open_file(temp_path, "wb") as f:
await f.write(serialized)
await temp_path.replace(self._checkpoint_path)
log.info(f"Checkpoint saved: {len(data.requests)} requests, {len(data.seen)} seen URLs")
except Exception as e:
# Clean up temp file if it exists
if await temp_path.exists():
await temp_path.unlink()
log.error(f"Failed to save checkpoint: {e}")
raise
async def load(self) -> Optional[CheckpointData]:
"""Load checkpoint data from disk.
Returns None if no checkpoint exists or if loading fails.
"""
if not await self.has_checkpoint():
return None
try:
async with await anyio.open_file(self._checkpoint_path, "rb") as f:
content = await f.read()
data: CheckpointData = pickle.loads(content)
log.info(f"Checkpoint loaded: {len(data.requests)} requests, {len(data.seen)} seen URLs")
return data
except Exception as e:
log.error(f"Failed to load checkpoint (starting fresh): {e}")
return None
async def cleanup(self) -> None:
"""Delete checkpoint file after successful completion."""
try:
if await self._checkpoint_path.exists():
await self._checkpoint_path.unlink()
log.debug("Checkpoint file cleaned up")
except Exception as e:
log.warning(f"Failed to cleanup checkpoint file: {e}")