Adding `async` and `await` support for Python 3.5

[gamesbrainiac]

Hi guys!

With the advent of async and await keywords in Python 3.5, I think we need to add some convenience methods to the connection object that is returned when we make a r.connect(... function call. This would not be difficult to do, because we can already do a yield r.connect anyways.

So, the proposal is to add an __await__ method to the connection object. This will not be hard to implement though, as you can see with aiohttp's await implementation:

@asyncio.coroutine
def __iter__(self):
    resp = yield from self._coro
    return resp
if PY_35:
    def __await__(self):
        resp = yield from self._coro
        return resp

[danielmewes]

👍

[Tryneus]

@gamesbrainiac - I'm not entirely sure what this issue is proposing. I tried out the existing asyncio implementation of the Python driver, and it appears to work correctly with async and await:

import rethinkdb as r
import asyncio

r.set_loop_type('asyncio')

async def run():
    conn = await r.connect('localhost')
    print('res: %d' % await r.expr(1).run(conn))
    await conn.close()

asyncio.get_event_loop().run_until_complete(run())

There is the possibility of extending the AsyncioCursor object to support __aiter__ according to PEP 0492. This would be fairly useful, as you currently cannot use cursors as iterators in any of the async backends for the Python driver.

[gamesbrainiac]

How does this work when neither Connection or ConnectionBase have a __await__ method inside of net_asyncio?

And yes, the idea was to implement both asynchronous iteration (__aiter__) as well as asynchronous context managers (__aenter__ and __aexit__) .

However, since doing nothing to the existing class worked, I'm curious to see of seeing if setting __await__ = __iter__ does the trick.

[XayOn]

Subscribing to this.

And yes, the idea was to implement both asynchronous iteration (aiter) as well as asynchronous context managers (aenter and aexit) .

That's really needed right now. I wonder how that'll behave with python3.4's decorated-style coroutines

However, since doing nothing to the existing class worked, I'm curious to see of seeing if setting await = iter does the trick.

I'd avoid this kind of things, they're obscure and make bugs hard to debug.

[dalanmiller]

AFAIRemember @gamesbrainiac my PR I linked below the await was working in the use case you described, but we held it back because the async for ... in ... and/or async with .... syntaxes were not complete and our Python tests were limited in testing the results properly. But you're welcome to try it out or give us a hand if this is your area of expertise!

Related to rethinkdb/rethinkdb#5354

[hansent]

👍

[foxx]

Really need this working, but it's not clear what the state of this feature is. rethinkdb/rethinkdb#5354 is waiting on a release according to @danielmewes. Are you accepting bug bounties to get this fixed sooner? If so, I can throw some cash at it. Or assistance with testing etc. Whatever is needed

[orokusaki]

Nudge.

I believe it's been about 4 months since I asked in the RethinkDB Slack channel. I was told, "that will be supported soon", and was sent here.

What's it going to take to get this feature added? Despite RethinkDB being a commercial company, I'm willing to donate $50 personally. @foxx mentioned a bug bounty. I'm sure there are others willing to pay to expedite this. I would offer a patch, but that's a paradox, because this feature is the thing holding me back from my first foray into RethinkDB (i.e., I know little about the source, etc.).

[foxx]

I'd happily throw $50 into this, maybe more if others don't step up

[danielmewes]

I'm moving this into the 2.3.x milestone, so that we can release it as a minor update before RethinkDB 2.4.

[dalanmiller]

@foxx @orokusaki would you guys mind testing out this branch here of the Python driver if you still have some time to give it a look?

rethinkdb/rethinkdb#5354

[orokusaki]

Awesome, thanks!

I just got into Europe for vacation (left my notebook home), but I will be testing this the moment I get back (toward end of month).

Sent from my iPhone

On Jul 9, 2016, at 12:24 AM, Daniel Alan Miller notifications@github.com wrote:

@foxx @orokusaki would you guys mind testing out this branch here of the Python driver if you still have some time to give it a look?

rethinkdb/rethinkdb#5354

—
You are receiving this because you were mentioned.
Reply to this email directly, view it on GitHub, or mute the thread.

[danielmewes]

@foxx @orokusaki Have you had a chance to try out the driver from branch dalanmiller_aiter_and_anext in the meantime?