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Code Issues Projects Releases Wiki Activity

Move journal locking code into new monitor.JournalLock class

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This commit is contained in:
Athanasius 2021-03-05 12:03:54 +00:00
parent 872f380831
commit c0e7be98f8
2 changed files with 75 additions and 51 deletions
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57
EDMarketConnector.py
View File

@ -10,7 +10,6 @@ import sys
import webbrowser
from builtins import object, str
from os import chdir, environ
from os import getpid as os_getpid
from os.path import dirname, isdir, join
from sys import platform
from time import localtime, strftime, time
@ -34,6 +33,7 @@ if __name__ == '__main__':
# After the redirect in case config does logging setup
from config import appversion, appversion_nobuild, config, copyright
from EDMCLogging import edmclogger, logger, logging
from monitor import JournalLock
if __name__ == '__main__': # noqa: C901
# Command-line arguments
@ -79,23 +79,11 @@ if __name__ == '__main__': # noqa: C901
"""
logger.trace('Begin...')
locked = journal_lock.journaldir_obtain_lock()
if platform == 'win32':
logger.trace('win32, using msvcrt')
# win32 doesn't have fcntl, so we have to use msvcrt
import msvcrt
logger.trace(f'journal_dir_lockfile = {journal_dir_lockfile!r}')
locked = False
try:
msvcrt.locking(journal_dir_lockfile.fileno(), msvcrt.LK_NBLCK, 4096)
except Exception as e:
logger.info(f"Exception: Couldn't lock journal directory \"{journal_dir}\""
f", assuming another process running: {e!r}")
locked = True
if locked:
if not locked:
# Need to do the check for this being an edmc:// auth callback
import ctypes
from ctypes.wintypes import BOOL, HWND, INT, LPARAM, LPCWSTR, LPWSTR
@ -177,28 +165,6 @@ if __name__ == '__main__': # noqa: C901
return False # Another instance is running
else:
logger.trace('NOT win32, using fcntl')
try:
import fcntl
except ImportError:
logger.warning("Not on win32 and we have no fcntl, can't use a file lock!"
"Allowing multiple instances!")
return True # Lie about there being no other instances
try:
fcntl.flock(journal_dir_lockfile, fcntl.LOCK_EX | fcntl.LOCK_NB)
except Exception as e:
logger.info(f"Exception: Couldn't lock journal directory \"{journal_dir}\","
f"assuming another process running: {e!r}")
return False
journal_dir_lockfile.write(f"Path: {journal_dir}\nPID: {os_getpid()}\n")
journal_dir_lockfile.flush()
logger.trace('Done')
return True
def already_running_popup():
@ -224,20 +190,9 @@ if __name__ == '__main__': # noqa: C901
root.mainloop()
journal_dir: str = config.get('journaldir') or config.default_journal_dir
# This must be at top level to guarantee the file handle doesn't go out
# of scope and get cleaned up, removing the lock with it.
journal_dir_lockfile_name = join(journal_dir, 'edmc-journal-lock.txt')
try:
journal_dir_lockfile = open(journal_dir_lockfile_name, mode='w+', encoding='utf-8')
journal_lock = JournalLock()
# Linux CIFS read-only mount throws: OSError(30, 'Read-only file system')
# Linux no-write-perm directory throws: PermissionError(13, 'Permission denied')
except Exception as e: # For remote FS this could be any of a wide range of exceptions
logger.warning(f"Couldn't open \"{journal_dir_lockfile_name}\" for \"w+\""
f" Aborting duplicate process checks: {e!r}")
else:
if journal_lock.journal_dir_lockfile:
if not no_other_instance_running():
# There's a copy already running.

69
monitor.py
View File

@ -2,6 +2,7 @@ from collections import defaultdict, OrderedDict
import json
import re
import threading
from os import getpid as os_getpid
from os import listdir, SEEK_SET, SEEK_END
from os.path import basename, expanduser, isdir, join
from sys import platform
@ -1021,3 +1022,71 @@ class EDLogs(FileSystemEventHandler): # type: ignore # See below
# singleton
monitor = EDLogs()
class JournalLock:
"""Handle locking of journal directory."""
def __init__(self):
"""Initialise where the journal directory and lock file are."""
self.journal_dir: str = config.get('journaldir') or config.default_journal_dir
self.journal_dir_lock = None
self.journal_dir_lockfile_name: str = join(self.journal_dir, 'edmc-journal-lock.txt')
try:
self.journal_dir_lockfile = open(self.journal_dir_lockfile_name, mode='w+', encoding='utf-8')
# Linux CIFS read-only mount throws: OSError(30, 'Read-only file system')
# Linux no-write-perm directory throws: PermissionError(13, 'Permission denied')
except Exception as e: # For remote FS this could be any of a wide range of exceptions
logger.warning(f"Couldn't open \"{self.journal_dir_lockfile_name}\" for \"w+\""
f" Aborting duplicate process checks: {e!r}")
def journaldir_obtain_lock(self) -> bool:
"""
Attempt to obtain a lock on the journal directory.
:return: bool - True if we successfully obtained the lock
"""
logger.trace(f'journal_dir_lockfile = {self.journal_dir_lockfile!r}')
if platform == 'win32':
logger.trace('win32, using msvcrt')
# win32 doesn't have fcntl, so we have to use msvcrt
import msvcrt
try:
msvcrt.locking(self.journal_dir_lockfile.fileno(), msvcrt.LK_NBLCK, 4096)
except Exception as e:
logger.info(f"Exception: Couldn't lock journal directory \"{self.journal_dir}\""
f", assuming another process running: {e!r}")
return False
else:
logger.trace('NOT win32, using fcntl')
try:
import fcntl
except ImportError:
logger.warning("Not on win32 and we have no fcntl, can't use a file lock!"
"Allowing multiple instances!")
return True # Lie about being locked
try:
fcntl.flock(self.journal_dir_lockfile, fcntl.LOCK_EX | fcntl.LOCK_NB)
except Exception as e:
logger.info(f"Exception: Couldn't lock journal directory \"{self.journal_dir}\","
f"assuming another process running: {e!r}")
return False
self.journal_dir_lockfile.write(f"Path: {self.journal_dir}\nPID: {os_getpid()}\n")
self.journal_dir_lockfile.flush()
logger.trace('Done')
return True
def journaldir_release_lock(self) -> bool:
"""Release lock on journal directory."""
pass