How to combine python asyncio with threads?

Question

I have successfully built a RESTful microservice with Python asyncio and aiohttp that listens to a POST event to collect realtime events from various feeders.

It the

Answer 1

Another alternative is to use loop.call_soon_threadsafe along with an asyncio.Queue as the intermediate channel of communication.

The current documentation for Python 3 also has a section on Developing with asyncio - Concurrency and Multithreading:

import asyncio

# This method represents your blocking code
def blocking(loop, queue):
    import time
    while True:
        loop.call_soon_threadsafe(queue.put_nowait, 'Blocking A')
        time.sleep(2)
        loop.call_soon_threadsafe(queue.put_nowait, 'Blocking B')
        time.sleep(2)

# This method represents your async code
async def nonblocking(queue):
    await asyncio.sleep(1)
    while True:
        queue.put_nowait('Non-blocking A')
        await asyncio.sleep(2)
        queue.put_nowait('Non-blocking B')
        await asyncio.sleep(2)

# The main sets up the queue as the communication channel and synchronizes them
async def main():
    queue = asyncio.Queue()
    loop = asyncio.get_running_loop()

    blocking_fut = loop.run_in_executor(None, blocking, loop, queue)
    nonblocking_task = loop.create_task(nonblocking(queue))

    running = True  # use whatever exit condition
    while running:
        # Get messages from both blocking and non-blocking in parallel
        message = await queue.get()
        # You could send any messages, and do anything you want with them
        print(message)

asyncio.run(main())

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