Firestore: Async callbacks on_snapshot

[NixBiks]

Problem

I am writing a bunch of python applications that listens to news on firestore using on_snapshot. Some of the callbacks have IO-bound tasks which blocks other callbacks and builds up a queue.

Here's a mockup demonstrating the issue

from google.cloud.firestore import Client
import time

def callback(col_snapshot, changes, read_time):
    print("Received updates")

    # mock IO-bound task
    time.sleep(1)
    print("Finished handling the updates")

Client().collection('news').on_snapshot(callback)

while True:
    pass

Solution

I'm no expert on this matter but I'm guessing that async is the right path. It would be great if something like this would be possible

from google.cloud.firestore import Client
import asyncio

async def callback(col_snapshot, changes, read_time):
    print("Received updates")

    # mock IO-bound task
    await asyncio.sleep(1)
    print("Finished handling the updates")

Client().collection('news').on_snapshot(callback)

while True:
    pass

** Alternatives **

I've also considered using multithreading but I think async is much preferred.

[BenWhitehead]

@crwilcox I'll have to defer to your knowledge here

[MaticConradi]

I'm looking forward to this. I'm using multiple snapshot listeners in my project where basically all operations are asynchronous, so this would be really handy

[therefromhere]

With google-api-core beginning to add AsyncIO support since version 1.18.0 it'd be awesome to get async support for firestore.

[NixBiks]

Any updates on this? I've noted that you've added some async and await code in v2 but I can't find anything about in the docs?

[crwilcox]

@mr-bjerre we did add a good amount of async surface to this client, though I don't believe we have made any changes to watch specifically. async_client, async_batch, async_collection, etc. Alongside their sync counter parts client, batch, async_collection, etc.

We had made #131 to track adding async watch support.

[craiglabenz]

Closing this as a duplicate of #131 (even though this came first).