With the advent of AI tools for coding, random side projects that used to live in my head finally see the light of day.

I’ve primarily been playing around with opencode for my personal use, an AI coding agent which by default has both a planning and building mode.

Rust and Python

For a while, I’ve been meaning to understand how to publish libraries for Python written in Rust. The significant speed-up provided by compute heavy libraries written in Rust such as pydantic, ruff, and uv has significantly changed the landscape of Python tools.

In a simple set up, both Python and Rust source code live in the same repository, in two separate folders. Rust is configured with Cargo.toml and Python with pyproject.toml.

Configuring the maturin build backend in pyproject.toml, and using pyo3 to provide bindings in the Rust code, compiling the Rust code and installing it into an existing virtual environment requires using just this commmand:

maturin develop

BACnet

Enter… a library for BACnet.

BACnet is an industrial protocol used primarily for communication with HVAC systems.

The current library widely used for BACnet communication is bacpypes and bacpypes3, and it is by far the most complete. However, I find the client initialisation clunky for use.

Implementation

I wanted the following design:

encoding-decoding portion of the library to be written in Rust
Rust portion should be Sans-IO
a light async wrapper in Python
use an async context manager for the client

This was designed and implemented with the help of opencode.

The result handles only BACnet/IP and can be found here.

A simple example of use is as follows:

import asyncio
from libbacnet import BacnetClient, BacnetAddr, ObjectIdentifier, PropertyIdentifier

async def main():
    async with BacnetClient(local_addr=("0.0.0.0", 47808)) as client:
        # Discover devices (3-second collection window)
        devices = await client.who_is(wait=3.0)
        print(f"Found {len(devices)} device(s)")

        for ev in devices:
            addr = BacnetAddr(ev.src.addr, ev.src.port)
            obj = ObjectIdentifier(object_type=8, instance=ev.message.device_id.instance)

            # Read the device object's description — returns a ReadPropertyResult
            result = await client.read_property(
                addr=addr,
                obj_id=obj,
                prop_id=PropertyIdentifier.DESCRIPTION,
            )
            print(f"  {addr} description: {result.value}")

asyncio.run(main())

Writing a Sans-IO Python library for BACnet in Rust

Rust and Python

BACnet

Implementation