two_devices example does not work!

[Yaro-o]

The example provided for connecting to two devices does not work on my device.

import asyncio
from bleak import BleakClient
notify_uuid = "00002A37-0000-1000-8000-00805F9B34FB"

def callback(characteristic, data):
    print(characteristic, data)

async def connect_to_device(address):
    print("starting", address, "loop")
    async with BleakClient(address, timeout=5.0) as client:
        print("connect to", address)
        try:
            await client.start_notify(notify_uuid, callback)
            await asyncio.sleep(10.0)
            await client.stop_notify(notify_uuid)
        except Exception as e:
            print(e)

    print("disconnect from", address)

def main(addresses):
    return asyncio.gather(*(connect_to_device(address) for address in addresses))

if __name__ == "__main__":
    asyncio.run(main(["A0:9E:1A:B5:E1:03", "A0:9E:1A:B5:EE:10" ]))

This code throws an error:
ValueError: a coroutine was expected, got <_GatheringFuture pending>

If I change the code a bit to make sure the ascyn functions are happy, I get another error as follows:

import asyncio
from bleak import BleakClient
notify_uuid = "00002A37-0000-1000-8000-00805F9B34FB"

def callback(characteristic, data):
    print(characteristic, data)

async def connect_to_device(address):
    print("starting", address, "loop")
    async with BleakClient(address, timeout=5.0) as client:
        print("connect to", address)
        try:
            await client.start_notify(notify_uuid, callback)
            await asyncio.sleep(10.0)
            await client.stop_notify(notify_uuid)
        except Exception as e:
            print(e)

    print("disconnect from", address)

async def main(addresses):
    return await asyncio.gather(*(connect_to_device(address) for address in addresses))

if __name__ == "__main__":
    asyncio.run(main(["A0:9E:1A:B5:E1:03", "A0:9E:1A:B5:EE:10" ]))

error:
bleak.exc.BleakDBusError: [org.bluez.Error.InProgress] Operation already in progress

Is there a better example for connecting to multiple devices? Where does the operation already in progress error originates from and how can I avoid it?

[dlech]

Yeah, trying to connect to two devices at the same time is usually asking for trouble. Maybe something like this would be better?

async def connect_to_device(address, lock):
    print("starting", address, "loop")
    try:
        with lock:
            client = BleakClient(address, timeout=5.0)
            await client.connect()
        try:
            print("connected to", address)
            await client.start_notify(notify_uuid, callback)
            await asyncio.sleep(10.0)
        finally:
            await client.disconnect()
            print("disconnect from", address)
    except Exception as e:
        print(e)


async def main(addresses):
    lock = asyncio.Lock()
    return await asyncio.gather(
        *(connect_to_device(address, lock) for address in addresses)
    )

[Yaro-o]

Worked like a charm. With one minor change. the "with lock" statement should be "async with lock".
Thanks again for your help