Question: why is `blocking` missing as a lock() parameter?

[jenstroeger]

Just a question: considering that Lock sports a blocking parameter:

redis-py/redis/lock.py

Lines 66 to 67 in a3cfded

	def __init__(self, redis, name, timeout=None, sleep=0.1,
	blocking=True, blocking_timeout=None, thread_local=True):

why is that same parameter missing from the lock() function:

redis-py/redis/client.py

Lines 708 to 709 in b940d07

	def lock(self, name, timeout=None, sleep=0.1, blocking_timeout=None,
	lock_class=None, thread_local=True):

which defaults to creating a Lock instance? It would be nice to write

r = redis.StrictRedis()
with r.lock("my-lock", blocking=False):
    pass  # Do stuff.

which would either enter the with block if the lock was acquired, or not. In my case, I wouldn’t even need the LockError() here… (Now if with had an else it would be even more useful, alas 😉)

[andymccurdy]

There's two things here. I assume that it's an oversight that the blocking arg is missing from Redis.lock(). We could probably add that.

However, when using a Lock as a context manager, raising the LockError exception is the only way to ensure that the body of the context manager doesn't execute. Lock.__enter__ explicitly passes blocking=True to Lock.acquire() regardless of how the Lock instance is configured.

[jenstroeger]

We could probably add that.

That’d be great! And I agree with what you say about raising the exception.

As for the context manager, I agree. It’s a Python oddity that I have to write

try:
    with …
        pass  # do stuff
except:
    pass  # handle errors

instead of the context manager handling errors, e.g.

with …
    pass  # do stuff
except:  # or use `else` would also be nice.
    pass  # handle errors

But that’s for a PEP discussion, not for here. There may have been one already…

[github-actions]

This issue is marked stale. It will be closed in 30 days if it is not updated.

[jenstroeger]

I assume that it's an oversight that the blocking arg is missing from Redis.lock(). We could probably add that.

@andymccurdy, want a PR?

[WisdomPill]

Hello @jenstroeger!

Maybe @chayim could answer your question.

I am also interested and ready to step in if needed.

[chayim]

@jenstroeger Would ❤️ a PR of course! Are you still interested?

[jenstroeger]

@chayim, happy to provide a PR but that’ll have to wait until end of the month. I’m really busy at the moment…

[WisdomPill]

@jenstroeger Any news? Otherwise I am available to step in

[jenstroeger]

Aya… I’ve been really busy lately. I can try to add this to my list next week, but can’t promise I’ll get it done 😕

[chayim]

@dvora-h Think you can get this in to the upcoming minor? It would be a nice addition to asyncio!