Writing a thread-safe class

Timothy Madden terminatorul at gmail.com
Sat Sep 12 01:26:34 CEST 2009


Hello

I would like to write a class with methods that can be accessed by many 
threads at the same time.

For this I have a lock attribute in my class obtained with 
threading.Lock(), in the constructor, and every method begins by 
acquiring the lock and ends by releasing it

My problem is that the lock is still an attribute of the class, and the 
very expression self.lock in the statement self.lock.acquire() is 
performed before locking, thus not being thread-safe.

If I am correct self is a dictionary of object attributes, and if 
another thread has the lock and creates a new attribute, or deletes one, 
in the same time with my lookup for self.lock, than the lookup is 
compromised.

How do people create thread-safe classes in python ?

Thank you,
Timothy Madden



More information about the Python-list mailing list