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Diffstat (limited to 'external_libs/python/lockfile-0.10.2/lockfile/pidlockfile.py')
| -rw-r--r-- | external_libs/python/lockfile-0.10.2/lockfile/pidlockfile.py | 193 |
1 files changed, 0 insertions, 193 deletions
diff --git a/external_libs/python/lockfile-0.10.2/lockfile/pidlockfile.py b/external_libs/python/lockfile-0.10.2/lockfile/pidlockfile.py deleted file mode 100644 index e92f9ead..00000000 --- a/external_libs/python/lockfile-0.10.2/lockfile/pidlockfile.py +++ /dev/null @@ -1,193 +0,0 @@ -# -*- coding: utf-8 -*- - -# pidlockfile.py -# -# Copyright © 2008–2009 Ben Finney <ben+python@benfinney.id.au> -# -# This is free software: you may copy, modify, and/or distribute this work -# under the terms of the Python Software Foundation License, version 2 or -# later as published by the Python Software Foundation. -# No warranty expressed or implied. See the file LICENSE.PSF-2 for details. - -""" Lockfile behaviour implemented via Unix PID files. - """ - -from __future__ import absolute_import - -import os -import sys -import errno -import time - -from . import (LockBase, AlreadyLocked, LockFailed, NotLocked, NotMyLock, - LockTimeout) - - -class PIDLockFile(LockBase): - """ Lockfile implemented as a Unix PID file. - - The lock file is a normal file named by the attribute `path`. - A lock's PID file contains a single line of text, containing - the process ID (PID) of the process that acquired the lock. - - >>> lock = PIDLockFile('somefile') - >>> lock = PIDLockFile('somefile') - """ - - def __init__(self, path, threaded=False, timeout=None): - # pid lockfiles don't support threaded operation, so always force - # False as the threaded arg. - LockBase.__init__(self, path, False, timeout) - dirname = os.path.dirname(self.lock_file) - basename = os.path.split(self.path)[-1] - self.unique_name = self.path - - def read_pid(self): - """ Get the PID from the lock file. - """ - return read_pid_from_pidfile(self.path) - - def is_locked(self): - """ Test if the lock is currently held. - - The lock is held if the PID file for this lock exists. - - """ - return os.path.exists(self.path) - - def i_am_locking(self): - """ Test if the lock is held by the current process. - - Returns ``True`` if the current process ID matches the - number stored in the PID file. - """ - return self.is_locked() and os.getpid() == self.read_pid() - - def acquire(self, timeout=None): - """ Acquire the lock. - - Creates the PID file for this lock, or raises an error if - the lock could not be acquired. - """ - - timeout = timeout is not None and timeout or self.timeout - end_time = time.time() - if timeout is not None and timeout > 0: - end_time += timeout - - while True: - try: - write_pid_to_pidfile(self.path) - except OSError as exc: - if exc.errno == errno.EEXIST: - # The lock creation failed. Maybe sleep a bit. - if timeout is not None and time.time() > end_time: - if timeout > 0: - raise LockTimeout("Timeout waiting to acquire" - " lock for %s" % - self.path) - else: - raise AlreadyLocked("%s is already locked" % - self.path) - time.sleep(timeout is not None and timeout/10 or 0.1) - else: - raise LockFailed("failed to create %s" % self.path) - else: - return - - def release(self): - """ Release the lock. - - Removes the PID file to release the lock, or raises an - error if the current process does not hold the lock. - - """ - if not self.is_locked(): - raise NotLocked("%s is not locked" % self.path) - if not self.i_am_locking(): - raise NotMyLock("%s is locked, but not by me" % self.path) - remove_existing_pidfile(self.path) - - def break_lock(self): - """ Break an existing lock. - - Removes the PID file if it already exists, otherwise does - nothing. - - """ - remove_existing_pidfile(self.path) - -def read_pid_from_pidfile(pidfile_path): - """ Read the PID recorded in the named PID file. - - Read and return the numeric PID recorded as text in the named - PID file. If the PID file cannot be read, or if the content is - not a valid PID, return ``None``. - - """ - pid = None - try: - pidfile = open(pidfile_path, 'r') - except IOError: - pass - else: - # According to the FHS 2.3 section on PID files in /var/run: - # - # The file must consist of the process identifier in - # ASCII-encoded decimal, followed by a newline character. - # - # Programs that read PID files should be somewhat flexible - # in what they accept; i.e., they should ignore extra - # whitespace, leading zeroes, absence of the trailing - # newline, or additional lines in the PID file. - - line = pidfile.readline().strip() - try: - pid = int(line) - except ValueError: - pass - pidfile.close() - - return pid - - -def write_pid_to_pidfile(pidfile_path): - """ Write the PID in the named PID file. - - Get the numeric process ID (“PID”) of the current process - and write it to the named file as a line of text. - - """ - open_flags = (os.O_CREAT | os.O_EXCL | os.O_WRONLY) - open_mode = 0o644 - pidfile_fd = os.open(pidfile_path, open_flags, open_mode) - pidfile = os.fdopen(pidfile_fd, 'w') - - # According to the FHS 2.3 section on PID files in /var/run: - # - # The file must consist of the process identifier in - # ASCII-encoded decimal, followed by a newline character. For - # example, if crond was process number 25, /var/run/crond.pid - # would contain three characters: two, five, and newline. - - pid = os.getpid() - line = "%(pid)d\n" % vars() - pidfile.write(line) - pidfile.close() - - -def remove_existing_pidfile(pidfile_path): - """ Remove the named PID file if it exists. - - Removing a PID file that doesn't already exist puts us in the - desired state, so we ignore the condition if the file does not - exist. - - """ - try: - os.remove(pidfile_path) - except OSError as exc: - if exc.errno == errno.ENOENT: - pass - else: - raise |