Question

How to lock django commands so it will not run twise in the same time?

Answer 1

Create a lock somewhere – I recently saw very simple lock implementation that used cache:

LOCK_EXPIRE = 60 * 5

lock_id = "%s-lock-%s" % (self.name, id_hexdigest) #computed earlier

is_locked = lambda: str(cache.get(lock_id)) == "true"
acquire_lock = lambda: cache.set(lock_id, "true", LOCK_EXPIRE)
release_lock = lambda: cache.set(lock_id, "nil", 1)

if not is_locked():
    aquire_lock()
    try:
        #do something
    finally:
        release_lock()

It’s just one of many possible implementations.

Edit: Corrected, I just pasted code without thinking. try...finally block is used to ensure that lock is always released, no matter what happens – but of course if statement is also necessary.