Assistance with BAC0 Experiments and Address in Use Error

[tgc1979]

Hi,

I’m new to BAC0 and have been experimenting with it in a test environment. Here’s a brief overview of my setup and the issues I’m encountering:

Setup
I created a Linux VM with two network adapters configured as follows:

Adapter 1: 192.168.0.10 (used in tests/manual_test.py)
Adapter 2: 192.168.0.50 (used in tests/manual_test_create_device.py)
Below are code snippets from the test scripts where I made changes:

Below are code snippets from the existing test code in the repo where I made changes:

tests/manual_test_create_device

sync def main():
    # We'll use 3 devices plus our main instance
    devip = "192.168.0.50/24"
    async with BAC0.start(localObjName="bacnet",ip=devip) as bacnet:
        async with BAC0.start(port=47809, localObjName="App1",ip=devip) as device_app:
            async with BAC0.start(port=47810, localObjName="App2",ip=devip) as device30_app:
                async with BAC0.start(port=47811, localObjName="App3",ip=devip) as device300_app:

tests/manual_test

async def main():
    # Configuration
    # # Initialize BACnet
    print(BAC0.infos.__version__)

    async with BAC0.start(ip="192.168.0.10/24") as bacnet:

        await bacnet._discover()
        lst = await bacnet._devices(_return_list=True)
        print(lst)

I am monitoring the traffic using Wireshark. When I start manual_test_create_device.py, I see BACnet communication from adapter 1 to adapter 1 on the specified ports. I believe the purpose of this test is not only to simulate devices but also to interact with them.

However, when I run manual_test.py, I expect to see "Who-Is" requests from adapter 2 to adapter 1, as both adapters are on the same subnet. Unfortunately, this does not happen because I encounter an "Address already in use" error.

Here’s the error traceback:

Exception in callback IPv4DatagramServer.set_broadcast_transport_protocol(<IPv4Address 192.168.0.10>)(<Task cancell...nit__.py:150>>)
handle: <Handle IPv4DatagramServer.set_broadcast_transport_protocol(<IPv4Address 192.168.0.10>)(<Task cancell...nit__.py:150>>)>
Traceback (most recent call last):
  File "/home/vboxuser/PycharmProjects/PythonProject/.venv/lib/python3.12/site-packages/bacpypes3/ipv4/__init__.py", line 159, in retrying_create_datagram_endpoint
    return await loop.create_datagram_endpoint(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/asyncio/base_events.py", line 1423, in create_datagram_endpoint
    raise exceptions[0]
  File "/usr/lib/python3.12/asyncio/base_events.py", line 1407, in create_datagram_endpoint
    sock.bind(local_address)
OSError: [Errno 98] Address already in use

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.12/asyncio/events.py", line 88, in _run
    self._context.run(self._callback, *self._args)
  File "/home/vboxuser/PycharmProjects/PythonProject/.venv/lib/python3.12/site-packages/bacpypes3/ipv4/__init__.py", line 207, in set_broadcast_transport_protocol
    transport, protocol = task.result()
                          ^^^^^^^^^^^^^
  File "/home/vboxuser/PycharmProjects/PythonProject/.venv/lib/python3.12/site-packages/bacpypes3/ipv4/__init__.py", line 167, in retrying_create_datagram_endpoint
    await asyncio.sleep(BACPYPES_ENDPOINT_RETRY_INTERVAL)
  File "/usr/lib/python3.12/asyncio/tasks.py", line 665, in sleep
    return await future
           ^^^^^^^^^^^^
asyncio.exceptions.CancelledError

My Observations and Questions
Address Already in Use

• I’m using two different IP addresses (192.168.0.10 and 192.168.0.50) on the same subnet, so I don’t expect a collision. Am I misunderstanding how the adapters or ports are being bound in BAC0?

Discovery Without _discover()

• In manual_test_create_device.py, the device named "bacnet" is somehow able to discover other devices without explicitly calling _discover().
• I added breakpoints in the "Who-Is" code but never hit them. How is discovery happening in this scenario?

Additional Information
I am using the latest version of BAC0 from the master branch.
Python version: 3.12
I would greatly appreciate your help in resolving these issues and understanding what might be wrong with my setup or logic.

Thank you!