b728fdd627
pm imported runtime_state's private helpers (_lock, _atomic_bytes, _bytes, _digest) at a dozen sites while runtime_state imports pm.environments at module top. The primitives are pm's: move them into the stdlib-only pm.filesystem as lock_fd, durable_write_bytes, read_bytes_or_none and file_digest, and repoint every pm caller. runtime_state keeps the private names only as import aliases: it still calls them through its own globals, and pre-PM updaters load them by these names mid-swap (tests/compat/old_updater_surface.json). Boot-subset test fixtures now copy pm/filesystem.py, since runtime_state imports it at process boot; worker-injection tests patch the name pm.publication now reads.
54 lines
1.8 KiB
Python
54 lines
1.8 KiB
Python
"""Cross-process ownership of resumable partials and their GC boundary."""
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from __future__ import annotations
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from contextlib import contextmanager
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import os
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from pathlib import Path
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import time
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from pm.filesystem import lock_fd
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@contextmanager
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def partial_lock(root: Path, key: str, *, cancelled=None, wait: bool = True):
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# Lock inodes must survive release: removing one lets a new owner lock a
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# different inode while an older waiter still holds the original handle.
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locks = root / ".locks"
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locks.mkdir(parents=True, exist_ok=True)
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fd = os.open(locks / key, os.O_CREAT | os.O_RDWR, 0o600)
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try:
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while not lock_fd(fd, wait=False):
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if not wait:
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yield False
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return
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if cancelled is not None and cancelled():
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yield False
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return
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time.sleep(0.05)
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yield True
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finally:
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os.close(fd)
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GC_GRACE_SECONDS = 6 * 60 * 60
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def collect_partials(root: Path, *, grace_seconds: float = GC_GRACE_SECONDS) -> None:
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"""Do not let a GC snapshot race a downloader acquiring ownership."""
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if not root.is_dir():
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return
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keys = {path.stem for path in root.iterdir() if path.suffix in {".part", ".ranges"}}
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now = time.time()
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for key in sorted(keys):
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with partial_lock(root, key, wait=False) as acquired:
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if not acquired:
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continue
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pair = [root / f"{key}{suffix}" for suffix in (".part", ".ranges")]
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try:
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if any(path.exists() and grace_seconds > 0 and now - path.stat().st_mtime < grace_seconds for path in pair):
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continue
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for path in pair:
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path.unlink(missing_ok=True)
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except OSError:
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continue # An inaccessible partial is not evidence it is unused.
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