Ausgabe der neuen DB Einträge
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2399 changed files with 843193 additions and 43 deletions
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# -*- test-case-name: twisted.application.runner.test.test_pidfile -*-
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# Copyright (c) Twisted Matrix Laboratories.
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# See LICENSE for details.
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"""
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PID file.
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"""
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import errno
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from os import getpid, kill, name as SYSTEM_NAME
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from zope.interface import Interface, implementer
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from twisted.logger import Logger
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class IPIDFile(Interface):
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"""
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Manages a file that remembers a process ID.
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"""
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def read():
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"""
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Read the process ID stored in this PID file.
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@return: The contained process ID.
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@rtype: L{int}
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@raise NoPIDFound: If this PID file does not exist.
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@raise EnvironmentError: If this PID file cannot be read.
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@raise ValueError: If this PID file's content is invalid.
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"""
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def writeRunningPID():
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"""
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Store the PID of the current process in this PID file.
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@raise EnvironmentError: If this PID file cannot be written.
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"""
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def remove():
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"""
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Remove this PID file.
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@raise EnvironmentError: If this PID file cannot be removed.
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"""
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def isRunning():
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"""
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Determine whether there is a running process corresponding to the PID
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in this PID file.
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@return: True if this PID file contains a PID and a process with that
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PID is currently running; false otherwise.
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@rtype: L{bool}
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@raise EnvironmentError: If this PID file cannot be read.
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@raise InvalidPIDFileError: If this PID file's content is invalid.
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@raise StalePIDFileError: If this PID file's content refers to a PID
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for which there is no corresponding running process.
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"""
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def __enter__():
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"""
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Enter a context using this PIDFile.
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Writes the PID file with the PID of the running process.
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@raise AlreadyRunningError: A process corresponding to the PID in this
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PID file is already running.
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"""
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def __exit__(excType, excValue, traceback):
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"""
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Exit a context using this PIDFile.
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Removes the PID file.
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"""
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@implementer(IPIDFile)
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class PIDFile(object):
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"""
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Concrete implementation of L{IPIDFile} based on C{IFilePath}.
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This implementation is presently not supported on non-POSIX platforms.
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Specifically, calling L{PIDFile.isRunning} will raise
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L{NotImplementedError}.
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"""
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_log = Logger()
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@staticmethod
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def _format(pid):
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"""
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Format a PID file's content.
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@param pid: A process ID.
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@type pid: int
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@return: Formatted PID file contents.
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@rtype: L{bytes}
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"""
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return u"{}\n".format(int(pid)).encode("utf-8")
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def __init__(self, filePath):
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"""
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@param filePath: The path to the PID file on disk.
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@type filePath: L{IFilePath}
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"""
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self.filePath = filePath
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def read(self):
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pidString = b""
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try:
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with self.filePath.open() as fh:
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for pidString in fh:
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break
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except OSError as e:
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if e.errno == errno.ENOENT: # No such file
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raise NoPIDFound("PID file does not exist")
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raise
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try:
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return int(pidString)
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except ValueError:
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raise InvalidPIDFileError(
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"non-integer PID value in PID file: {!r}".format(pidString)
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)
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def _write(self, pid):
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"""
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Store a PID in this PID file.
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@param pid: A PID to store.
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@type pid: L{int}
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@raise EnvironmentError: If this PID file cannot be written.
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"""
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self.filePath.setContent(self._format(pid=pid))
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def writeRunningPID(self):
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self._write(getpid())
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def remove(self):
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self.filePath.remove()
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def isRunning(self):
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try:
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pid = self.read()
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except NoPIDFound:
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return False
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if SYSTEM_NAME == "posix":
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return self._pidIsRunningPOSIX(pid)
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else:
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raise NotImplementedError(
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"isRunning is not implemented on {}".format(SYSTEM_NAME)
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)
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@staticmethod
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def _pidIsRunningPOSIX(pid):
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"""
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POSIX implementation for running process check.
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Determine whether there is a running process corresponding to the given
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PID.
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@return: True if the given PID is currently running; false otherwise.
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@rtype: L{bool}
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@raise EnvironmentError: If this PID file cannot be read.
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@raise InvalidPIDFileError: If this PID file's content is invalid.
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@raise StalePIDFileError: If this PID file's content refers to a PID
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for which there is no corresponding running process.
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"""
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try:
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kill(pid, 0)
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except OSError as e:
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if e.errno == errno.ESRCH: # No such process
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raise StalePIDFileError(
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"PID file refers to non-existing process"
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)
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elif e.errno == errno.EPERM: # Not permitted to kill
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return True
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else:
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raise
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else:
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return True
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def __enter__(self):
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try:
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if self.isRunning():
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raise AlreadyRunningError()
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except StalePIDFileError:
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self._log.info("Replacing stale PID file: {log_source}")
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self.writeRunningPID()
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return self
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def __exit__(self, excType, excValue, traceback):
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self.remove()
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@implementer(IPIDFile)
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class NonePIDFile(object):
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"""
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PID file implementation that does nothing.
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This is meant to be used as a "active None" object in place of a PID file
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when no PID file is desired.
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"""
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def __init__(self):
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pass
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def read(self):
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raise NoPIDFound("PID file does not exist")
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def _write(self, pid):
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"""
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Store a PID in this PID file.
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@param pid: A PID to store.
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@type pid: L{int}
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@raise EnvironmentError: If this PID file cannot be written.
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@note: This implementation always raises an L{EnvironmentError}.
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"""
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raise OSError(errno.EPERM, "Operation not permitted")
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def writeRunningPID(self):
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self._write(0)
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def remove(self):
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raise OSError(errno.ENOENT, "No such file or directory")
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def isRunning(self):
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return False
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def __enter__(self):
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return self
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def __exit__(self, excType, excValue, traceback):
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pass
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nonePIDFile = NonePIDFile()
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class AlreadyRunningError(Exception):
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"""
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Process is already running.
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"""
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class InvalidPIDFileError(Exception):
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"""
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PID file contents are invalid.
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"""
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class StalePIDFileError(Exception):
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"""
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PID file contents are valid, but there is no process with the referenced
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PID.
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"""
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class NoPIDFound(Exception):
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"""
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No PID found in PID file.
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"""
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