Hi Nickolai,

Thanks for your suggestions, especially for the file system lock: We don't have often locks, but we must be sure it's locked.

For 1) and 4) suggestions, in fact we have several systems to sync and also a PostgreSQL transaction, the request must be treated by the same worker from beginning to end and the other systems aren't idempotent at all, it's "old-school" proprietary systems, good luck to change that ;-)

Ludovic Gasc (GMLudo)

2018-04-17 12:46 GMT+02:00 Nickolai Novik <nickolainovik@gmail.com>:
Hi, redis lock has own limitations and depending on your use case it may or may not be suitable [1]. If possible I would redefine problem and also considered:
1) create worker per specific resource type to avoid locking
2) optimistic locking
3) File system lock like in twisted, but not sure about performance and edge cases there

On Tue, 17 Apr 2018 at 13:01 Ludovic Gasc <gmludo@gmail.com> wrote:
Hi Roberto,

Thanks for the pointer, it's exactly the type of feedbacks I'm looking for: Ideas that are out-of-box of my confort zone.
However, in our use case, we are using gunicorn, that uses forks instead of multiprocessing to my knowledge, I can't use multiprocessing without to remove gunicorn.

If somebody is using aioredlock in his project, I'm interested by feedbacks.

Have a nice week.

Ludovic Gasc (GMLudo)

2018-04-17 7:19 GMT+02:00 Roberto Martínez <robertomartinezp@gmail.com>:


I don't know if there is a third party solution for this.

I think the closest you can get today using the standard library is using a multiprocessing.manager().Lock (which can be shared among processes) and call the lock.acquire() function with asyncio.run_in_executor(), using a ThreadedPoolExecutor to avoid blocking the asyncio event loop.

Best regards,

El mar., 17 abr. 2018 a las 0:05, Ludovic Gasc (<gmludo@gmail.com>) escribió:

I'm looking for a equivalent of asyncio.Lock (https://docs.python.org/3/library/asyncio-sync.html#asyncio.Lock) but shared between several processes on the same server, because I'm migrating a daemon from mono-worker to multi-worker pattern.

For now, the closest solution in term of API seems aioredlock: https://github.com/joanvila/aioredlock#aioredlock
But I'm not a big fan to use polling nor with a timeout because the lock I need is very critical, I prefer to block the code than unlock with timeout.

Do I miss a new awesome library or do you have an easier approach ?

Thanks for your responses.
Ludovic Gasc (GMLudo)