分布式锁-Redis方案

 #!/usr/bin/env python
 # coding=utf-8

 import time
 import redis

 class RedisLock(object):
     def __init__(self, key):
         self.rdcon = redis.Redis(host='', port=6379, password="", db=1)
         self._lock = 0
         self.lock_key = "%s_dynamic_test" % key

     @staticmethod
     def get_lock(cls, timeout=10):
         while cls._lock != 1:
             timestamp = time.time() + timeout + 1
             cls._lock = cls.rdcon.setnx(cls.lock_key, timestamp)
 　　　　　　　# 注意下方括号的范围
             if cls._lock == 1 or (time.time() > cls.rdcon.get(cls.lock_key) and time.time() > cls.rdcon.getset(cls.lock_key, timestamp)):
                 print "get lock"
                 break
             else:
                 time.sleep(0.3)

     @staticmethod
     def release(cls):
         if time.time() < cls.rdcon.get(cls.lock_key):
             print "release lock"
             cls.rdcon.delete(cls.lock_key)

 def deco(cls):
     def _deco(func):
         def __deco(*args, **kwargs):
             print "before %s called [%s]."%(func.__name__, cls)
             cls.get_lock(cls)
             try:
                 return func(*args, **kwargs)
             finally:
                 cls.release(cls)
         return __deco
     return _deco

 @deco(RedisLock(""))
 def myfunc():
     print "myfunc() called."
     time.sleep(20)

 if __name__ == "__main__":
     myfunc()

eg2:

 import redis
 import time, datetime

 def acquire_lock(conn, lockname, identifier, expire=10):
     if conn.setnx(lockname, identifier):
         conn.expire(lockname, expire)
         return identifier
     elif not conn.ttl(lockname):
         conn.expire(lockname, expire)

     return False

 def release_lock(conn, lockname, identifier):
     pipe = conn.pipeline(True)
     while True:
         try:
             pipe.watch(lockname)
             if pipe.get(lockname) == identifier:
                 pipe.multi()
                 pipe.delete(lockname)
                 pipe.execute()
                 return True
             pipe.unwatch()
             break
         except redis.exceptions.WatchError:
             pass

     # we lost the lock
     return False

 conn = redis.Redis(host='localhost', port=6379, db=0)

 # 1 identifier
 # 2 False
 # 11 True
 # 22 False
 # 33 barx2
 # 44 True

 ret = acquire_lock(conn, "lockname", "identifier", 3)
 print "", ret
 ret = acquire_lock(conn, "lockname", "identifier", 3)
 print "", ret
 ret = release_lock(conn, "lockname", "identifier")
 print "", ret
 ret = release_lock(conn, "lockname", "identifier")
 print "", ret

 ret = acquire_lock(conn, "footest", "bartest", 10)
 print "", ret