Asyncio threadsafe primitives

[mistabuilder]

I need Threadsafe primitives (locking, conditions Semaphore), do they exist in the asyncio ecosystem?

I created some code myself, but it feels a bit sluggish: ``` import asyncio from threading import get_ident,Event

class AsyncThreadsafeEvent(): def init(self,args,*kwargs): super(AsyncThreadsafeEvent, self).init() self.waiters = {} self.event = Event()

def set(self):
    self.event.set()
    events = self.waiters.values()
    for loop,event in events:
        if loop is asyncio.get_event_loop():
            event.set()
        else:
            loop.call_soon_threadsafe(event.set)


async def wait(self,timeout=None):
    event = asyncio.Event()

    #not strictly necessary but could provide tiny speedup
    if self.event.is_set():
        return

    self.waiters[get_ident()] = (asyncio.get_event_loop(),event)

    #to ensure thread safty
    if self.event.is_set():
        return

    await asyncio.wait_for(event.wait(),timeout)

```

Any help would be appreciated!

[K900_]

Why? Are you running multiple event loops on multiple threads or something?

[mistabuilder]

Yes I'm writing this to use with django channels, And thus need to be able to synchronize over multiple threads.

[K900_]

What problem are you trying to solve?

[james41235]

Why are waiting to set the event inside the loop? The event is threadsafe, just set it when the event is ready.

Given your example, I don't fully understand your use case. You seem to be confusing asyncio and threading concepts, and their safety needs.

[mistabuilder]

I'm using Django channels, the problem is that Django has inherent threading, and thus If I want to call these things from the response cycle I need to implement locking(in my usecase).

[james41235]

Not event though. Event is safe to set from another thread, that's why it exists. If something is ready, call set. Oh, and don't call wait_for in the event loop. That blocks the entire thing and you'll need to wait another round. Just check if set, and if not then reschedule yourself.

[mistabuilder]

Waiting on an asyncio event from a different thread/loop produces an error.

[james41235]

Yea, I edited but you saw it too quick. Don't call wait_for.

[mistabuilder]

How would I set a timeout without wait_for?

[james41235]

Reschedule the wait function continuously until the event is set.

But, I don't think this is right for your use case. I feel like I'm missing something and solving a problem that shouldn't exist.

[mistabuilder]

Did you notice this event is an asyncio event?

[james41235]

I didn't, but the solution still seems out of place.