Browse an OPC UA server and read a machine's variables (Python)

"""Browse an OPC UA server for a named object and print its variable values.

Usage:  python opcua_reader.py opc.tcp://192.168.0.20:4840/machine/ CNC-01
"""

import asyncio
import sys

from asyncua import Client


async def read_machine(url, object_name):
    async with Client(url=url) as client:
        objects = client.get_objects_node()
        children = await objects.get_children()

        target = None
        for child in children:
            name = (await child.read_browse_name()).Name
            if name == object_name:
                target = child
                break

        if target is None:
            names = [(await c.read_browse_name()).Name for c in children]
            sys.exit(f"'{object_name}' not found under Objects. Available: {names}")

        for var in await target.get_children():
            name = (await var.read_browse_name()).Name
            try:
                value = await var.read_value()
            except Exception as e:
                value = f"<not readable: {e}>"
            print(f"{name}: {value}")


def main():
    if len(sys.argv) < 3:
        sys.exit("Usage: python opcua_reader.py <endpoint-url> <object-name>")
    asyncio.run(read_machine(sys.argv[1], sys.argv[2]))


if __name__ == "__main__":
    main()