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#! /usr/bin/env python |
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import sys |
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import os |
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import tempfile |
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class SingleInstanceException(BaseException): |
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pass |
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class SingleInstance: |
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""" |
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If you want to prevent your script from running in parallel just instantiate SingleInstance() class. |
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If is there another instance already running it will throw a `SingleInstanceException`. |
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>>> import tendo |
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... me = SingleInstance() |
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This option is very useful if you have scripts executed by crontab at small amounts of time. |
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Remember that this works by creating a lock file with a filename based on the full path to the script file. |
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Providing a flavor_id will augment the filename with the provided flavor_id, allowing you to create |
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multiple singleton instances from the same file. This is particularly useful if you want specific |
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functions to have their own singleton instances. |
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""" |
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def __init__(self, flavor_id=""): |
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import sys |
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self.initialized = False |
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basename = os.path.splitext(os.path.abspath(sys.argv[0]))[0].replace( |
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"/", "-").replace(":", "").replace("\\", "-") + '-%s' % flavor_id + '.lock' |
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# os.path.splitext(os.path.abspath(sys.modules['__main__'].__file__))[0].replace("/", "-"). |
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# replace(":", "").replace("\\", "-") + '-%s' % flavor_id + '.lock' |
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self.lockfile = os.path.normpath( |
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tempfile.gettempdir() + '/' + basename) |
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if sys.platform == 'win32': |
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try: |
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# file already exists, we try to remove (in case previous |
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# execution was interrupted) |
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if os.path.exists(self.lockfile): |
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os.unlink(self.lockfile) |
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self.fd = os.open( |
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self.lockfile, os.O_CREAT | os.O_EXCL | os.O_RDWR) |
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except OSError: |
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type, e, tb = sys.exc_info() |
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if e.errno == 13: |
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return |
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else: # non Windows |
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import fcntl |
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self.fp = open(self.lockfile, 'w') |
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self.fp.flush() |
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try: |
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fcntl.lockf(self.fp, fcntl.LOCK_EX | fcntl.LOCK_NB) |
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except IOError: |
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return |
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self.initialized = True |
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def __del__(self): |
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import sys |
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import os |
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if not self.initialized: |
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return |
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try: |
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if sys.platform == 'win32': |
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if hasattr(self, 'fd'): |
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os.close(self.fd) |
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os.unlink(self.lockfile) |
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else: |
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import fcntl |
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fcntl.lockf(self.fp, fcntl.LOCK_UN) |
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# os.close(self.fp) |
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if os.path.isfile(self.lockfile): |
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os.unlink(self.lockfile) |
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except Exception as e: |
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raise |
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def f(name): |
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# tmp = logger.level |
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# logger.setLevel(logging.CRITICAL) # we do not want to see the warning |
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try: |
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me2 = SingleInstance(flavor_id=name) # noqa |
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except SingleInstanceException: |
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sys.exit(-1) |
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# logger.setLevel(tmp) |
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pass |
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QTodoTxt /
QTodoTxt2
