bluetooth : After timeout, reconnection is successful. (Peripherals are always powered off)

[63rabbits]

The other devise is turned off. However, after a timeout, when you retry, it appears to be connected. In reality, it has failed.

The solution is described below.I would like the fix code to be put in the correct place. Where can I report this?
I'm not a native speaker so sorry if my sentences are weird.

• Environment

  • Raspberry Pi Pico W with RP2040
  • MicroPython v1.24.0 on 2024-10-25
  • IDE:Thonny

• Steps to reproduce

  1. Power off the peripheral device.
  2. Timeout occurs when trying to connect.
  3. Retry and the connection succeeds. (It actually fails.)

• Code used for testing

from micropython import const
import asyncio
import aioble
# import test_aioble as aioble

import sys


_TARGET_DEVICE_ADDR = const("d7:de:4c:f4:56:e5")


async def gather(ai):
    ret=[]
    async for x in ai: ret.append(x)
    return ret


async def device_details(connection):

    if connection is None:
        return

    try:
        services = await gather(connection.services())
    except asyncio.TimeoutError as e:
        print("Timeout. (discovering services)")
        sys.print_exception(e)
    except Exception as e:
        print("Error (discovering services): {}".format(e))
        sys.print_exception(e)
    else:
        if services is None or len(services) <= 0:
            print("\n\"Service\" not found.")
            return
        
        for s in services:
            print("\t", s)


async def print_details(device):

    connection = None

    # connecting to device
    try:
        print("\nConnecting to {} ... ".format(device), end="")
        connection = await device.connect(timeout_ms=2000)
    except asyncio.TimeoutError as e:
        print("Timeout.")
        sys.print_exception(e)
    except Exception as e:
        print("Error: {}".format(e))
        sys.print_exception(e)
    else:
        print("Connected.")
        await device_details(connection)
        await connection.disconnect()


async def main():

    device = aioble.Device(aioble.ADDR_RANDOM, _TARGET_DEVICE_ADDR)

    while True:
        await print_details(device)
        r = input("\nenter return (to retry) / q(uit). > ").strip()
        if r.upper() == "Q":
            sys.exit(0)


asyncio.run(main())

• Output

MPY: soft reboot
MicroPython v1.24.0 on 2024-10-25; Raspberry Pi Pico W with RP2040

Type "help()" for more information.

>>> 

>>> %Run -c $EDITOR_CONTENT

MPY: soft reboot

Connecting to Device(ADDR_RANDOM, d7:de:4c:f4:56:e5) ... Timeout.
Traceback (most recent call last):
  File "<stdin>", line 47, in print_details
  File "aioble/device.py", line 149, in connect
  File "aioble/central.py", line 140, in _connect
  File "aioble/device.py", line 94, in __exit__
TimeoutError: 

enter return (to retry) / q(uit). > 

Connecting to Device(ADDR_RANDOM, d7:de:4c:f4:56:e5, CONNECTED) ... Connected.
Error (discovering services): can't convert NoneType to int
Traceback (most recent call last):
  File "<stdin>", line 24, in device_details
  File "<stdin>", line 14, in gather
  File "aioble/client.py", line 128, in __anext__
  File "aioble/client.py", line 120, in _start
  File "aioble/client.py", line 193, in _start_discovery
TypeError: can't convert NoneType to int

enter return (to retry) / q(uit). > 

• How to fix it
  I added exception handling because of the following problem. (It is not a good idea to fix it in this place.)
  • When the timeout occurs, the variable "_connection" in aioble is not in the correct state.
  • When the timeout occurs, the internal state of the module "bluetooth" seems to remain connected.

# https://github.com/micropython/micropython-lib/blob/master/micropython/bluetooth/aioble/aioble/central.py#L107

async def _connect(
    connection, timeout_ms, scan_duration_ms, min_conn_interval_us, max_conn_interval_us
):

                << Omitted >>

    try:
        with DeviceTimeout(None, timeout_ms):
            ble.gap_connect(
                device.addr_type,
                device.addr,
                scan_duration_ms,
                min_conn_interval_us,
                max_conn_interval_us,
            )

            # Wait for the connected IRQ.
            await connection._event.wait()
            assert connection._conn_handle is not None

            # Register connection handle -> device.
            DeviceConnection._connected[connection._conn_handle] = connection
    except:
        device._connection = None
        ble.gap_connect(None)
        raise
    finally:
        # After timeout, don't hold a reference and ignore future events.
        _connecting.remove(device)

[bidrohini]

I think it will be better if you create an 'issue' in the repo.

[63rabbits]

I will do so.
Sorry for the late reply.

[ekspla]

While I might be not quite sure of the intension of your code, I would suggest you to test the state by using
if connection.is_connected(): statement.

async def print_details(device):

    connection = None

    # connecting to device
    try:
        print("\nConnecting to {} ... ".format(device), end="")
        connection = await device.connect(timeout_ms=2000)
    except asyncio.TimeoutError as e:
        print("Timeout.")
        sys.print_exception(e)
    except Exception as e:
        print("Error: {}".format(e))
        sys.print_exception(e)
    else:
        if connection.is_connected():
            print("Connected.")
            await device_details(connection)
        else:
            print("Disconnected.")
        await connection.disconnect()

[63rabbits]

I tried it and it worked. This avoids the problem for now. Thank you very much.

I found out the following things this time.

• print(device)
  If the _connection object exists, “CONNECTED” is printed.
  https://github.com/micropython/micropython-lib/blob/master/micropython/bluetooth/aioble/aioble/device.py#L125

• connection.is_connected()
  True if the _conn_handle object exists.
  https://github.com/micropython/micropython-lib/blob/master/micropython/bluetooth/aioble/aioble/device.py#L267

In summary, it is understood that the following states are possible, whether good or bad.

#	connection obj	connection handle	print(device)	is_connected()
1	✔︎		"CONNECTED"	False
2	✔︎	✔︎	"CONNECTED"	True

I have created an “issue” below.
micropython/micropython-lib#950