mirror of
https://github.com/Stone-Red-Code/dvc.git
synced 2026-11-06 07:18:28 +01:00
151 lines
4.2 KiB
Python
151 lines
4.2 KiB
Python
"""Manages dvc lock file."""
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import hashlib
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import os
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import time
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from datetime import timedelta
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import flufl.lock
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import zc.lockfile
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from dvc.exceptions import DvcException
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from dvc.progress import Tqdm
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from dvc.utils import format_link
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DEFAULT_TIMEOUT = 5
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FAILED_TO_LOCK_MESSAGE = (
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"cannot perform the command because another DVC process seems to be "
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"running on this project. If that is not the case, manually remove "
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"`.dvc/tmp/lock` and try again."
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)
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class LockError(DvcException):
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"""Thrown when unable to acquire the lock for DVC repo."""
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class Lock:
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"""Class for DVC repo lock.
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Uses zc.lockfile as backend.
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"""
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def __init__(self, lockfile, friendly=False, **kwargs):
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self._friendly = friendly
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self.lockfile = lockfile
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self._lock = None
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@property
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def files(self):
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return [self.lockfile]
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def _do_lock(self):
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try:
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with Tqdm(
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bar_format="{desc}",
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disable=not self._friendly,
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desc=(
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"If DVC froze, see `hardlink_lock` in {}".format(
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format_link("https://man.dvc.org/config#core")
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)
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),
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):
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self._lock = zc.lockfile.LockFile(self.lockfile)
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except zc.lockfile.LockError:
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raise LockError(FAILED_TO_LOCK_MESSAGE)
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def lock(self):
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try:
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self._do_lock()
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return
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except LockError:
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time.sleep(DEFAULT_TIMEOUT)
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self._do_lock()
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def unlock(self):
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self._lock.close()
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self._lock = None
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@property
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def is_locked(self):
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return bool(self._lock)
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def __enter__(self):
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self.lock()
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def __exit__(self, typ, value, tbck):
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self.unlock()
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class HardlinkLock(flufl.lock.Lock):
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"""Class for DVC repo lock.
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Args:
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lockfile (str): the lock filename
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in.
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tmp_dir (str): a directory to store claim files.
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"""
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def __init__(
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self, lockfile, tmp_dir=None, **kwargs
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): # pylint: disable=super-init-not-called
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import socket
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self._tmp_dir = tmp_dir
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# NOTE: this is basically Lock.__init__ copy-paste, except that
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# instead of using `socket.getfqdn()` we use `socket.gethostname()`
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# to speed this up. We've seen [1] `getfqdn()` take ~5sec to return
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# anything, which is way too slow. `gethostname()` is actually a
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# fallback for `getfqdn()` when it is not able to resolve a
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# canonical hostname through network. The claimfile that uses
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# `self._hostname` is still usable, as it uses `pid` and random
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# number to generate the resulting lock file name, which is unique
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# enough for our application.
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#
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# [1] https://github.com/iterative/dvc/issues/2582
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self._hostname = socket.gethostname()
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self._lockfile = lockfile
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self._lifetime = timedelta(days=365) # Lock for good by default
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self._separator = flufl.lock.SEP
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self._set_claimfile()
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self._owned = True
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self._retry_errnos = []
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@property
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def lockfile(self):
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return self._lockfile
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def lock(self): # pylint: disable=arguments-differ
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try:
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super().lock(timedelta(seconds=DEFAULT_TIMEOUT))
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except flufl.lock.TimeOutError:
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raise LockError(FAILED_TO_LOCK_MESSAGE)
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def _set_claimfile(self, pid=None):
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super()._set_claimfile(pid)
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if self._tmp_dir is not None:
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# Under Windows file path length is limited so we hash it
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filename = hashlib.md5(self._claimfile.encode()).hexdigest()
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self._claimfile = os.path.join(self._tmp_dir, filename + ".lock")
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# Fix for __del__ bug in flufl.lock [1] which is causing errors on
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# Python shutdown [2].
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# [1] https://gitlab.com/warsaw/flufl.lock/issues/7
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# [2] https://github.com/iterative/dvc/issues/2573
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def __del__(self):
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try:
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if self._owned:
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self.finalize()
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except ImportError:
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pass
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def make_lock(lockfile, tmp_dir=None, friendly=False, hardlink_lock=False):
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cls = HardlinkLock if hardlink_lock else Lock
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return cls(lockfile, tmp_dir=tmp_dir, friendly=friendly)
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