lock-01.py

# -*- coding: utf-8 -*-
import os
try:
    from gevent import sleep
except:
    from time import sleep


class LockFail(Exception):
    pass


class Locker(object):
    def __init__(self, lockfile, retry=1, timesleep=1.0):
        """use physical file to handle lock"""
        self.lockfile = lockfile
        self.retry = retry
        self.timesleep = timesleep

    def __enter__(self):
        retry = self.retry
        last_lock_fail = None
        while retry > 0:
            retry -= 1
            try:
                if os.path.exists(self.lockfile):
                    raise LockFail('lockfile: `%s` is existed for another lock.' % self.lockfile)
                with open(self.lockfile, 'w+') as fp:
                    fp.write(str(os.getpid()))
                    self.last_lock_fail = None
                    break
            except LockFail as error:
                self.last_lock_fail = error
                sleep(self.timesleep)

        if last_lock_fail:
            raise last_lock_fail

        return self

    def __exit__(self, exc_type, exc_value, traceback):
        os.remove(self.lockfile)


if __name__ == '__main__':
    import gevent
    with Locker('testlock', retry=3, timesleep=3) as lock:
        for i in range(0, 3):
            print i
            gevent.sleep(1)

lock-02.py

# -*- coding: utf-8 -*-
import contextlib
import os


class LockFail(Exception):
    pass


@contextlib.contextmanager
def lock(filepath):
    """use physical file to handle lock"""
    if os.path.exists(filepath):
        raise LockFail('lockfile: %s is existed for another lock.' % filepath)
    with open(filepath, 'w+') as fp:
        fp.write(str(os.getpid()))
    yield
    os.remove(filepath)


if __name__ == '__main__':
    import gevent


    def task():
        with lock('locktest'):
            for i in range(0, 10):
                gevent.sleep(1)
                print "sleep", os.getpid()
    glets = []
    for i in range(0, 10):
        #lock('locktest')
        glets.append(gevent.spawn(task))

    gevent.joinall(glets)