Using a global dictionary with threads in Python

Question

Is accessing/changing dictionary values thread-safe?

I have a global dictionary foo and multiple threads with ids id1, id2, ..

Answer 1

Since I needed something similar, I landed here. I sum up your answers in this short snippet :

#!/usr/bin/env python3

import threading

class ThreadSafeDict(dict) :
    def __init__(self, * p_arg, ** n_arg) :
        dict.__init__(self, * p_arg, ** n_arg)
        self._lock = threading.Lock()

    def __enter__(self) :
        self._lock.acquire()
        return self

    def __exit__(self, type, value, traceback) :
        self._lock.release()

if __name__ == '__main__' :

    u = ThreadSafeDict()
    with u as m :
        m[1] = 'foo'
    print(u)

as such, you can use the with construct to hold the lock while fiddling in your dict()