Specifying `blocking` and `timeout` when acquiring lock as a context manager

[Neil D. Cerutti]

On 8/8/2014 9:25 AM, Ethan Furman wrote:
> On 08/08/2014 04:51 AM, cool-RR wrote:
>>
>> If I want to acquire a `threading.Lock` using the context manager
>> protocol,
>>  is it possible to specify the `blocking` and `timeout` arguments that
>>  `acquire` would usually take?
>
> Not that I know of, but why would you want to?  There's no built-in 'if'
> with a 'with' block -- how would your code know whether it ran or not?

Perhaps defer release, a la a common Go pattern:

with contextlib.ExitStack() as stack:
     acquired = lock.acquire(blocking=False)
     if acquired:
         stack.callback(lock.release)
         do_stuff

-- 
Neil Cerutti