[Bug]: Error when connecting to OPCUA server with plc4go

[telmobarrena98]

What happened?

I am launching an OPCUA server through Docker running the following .py file:

import asyncio
import logging
import random
from asyncua import Server, ua

async def main():
    _logger = logging.getLogger("asyncua")
    # setup our server
    server = Server()
    await server.init()
    server.set_endpoint("opc.tcp://0.0.0.0:4840/freeopcua/server/")

    # setup our own namespace, not really necessary but should as spec
    uri = "http://examples.freeopcua.github.io"
    idx = await server.register_namespace(uri)
    ns = "ns=2;s=freeopcua.Tags.pressure"
    ns2 = "ns=2;s=freeopcua.Tags.temperature"

    min_val = -0.5
    max_val = 0.6

    # populating our address space
    # server.nodes, contains links to very common nodes like objects and root
    myobj = await server.nodes.objects.add_object(idx, "MyObject")
    pressure = await myobj.add_variable(ns, "MyVariable", 10.5)
    temperature = await myobj.add_variable(ns2, "MyVariable", 26.7)
    # Set MyVariable to be writable by clients
    await pressure.set_writable()
    await temperature.set_writable()
    opcs = [ pressure, temperature ]

    _logger.info("Starting server!")
    async with server:
        while True:
            await asyncio.sleep(100)
            random_counter = random.uniform(min_val, max_val)
            for opc in opcs:
                new_val = await opc.get_value() + random_counter
                if(new_val>100.0):
                    new_val=100.0
                elif(new_val<0.0):
                    new_val=0.0
                _logger.info("Set value of %s to %.1f", opc, new_val)
                await opc.write_value(new_val)

if __name__ == "__main__":
    logging.basicConfig(level=logging.DEBUG)
    asyncio.run(main(), debug=True)

. I am able to connect to it with UA Expert. However, when using the opcua driver of plc4go, i get this error in the server side: raise ua.UaError(f"Unsupported message type {header.MessageType}") asyncua.ua.uaerrors._base.UaError: Unsupported message type b'\x00\x00\x00 and this one on the .go file: Error connecting to PLC: Error during connection: timeout after 5s

Version

v1.23.1

Programming Languages

• [ ] plc4j
• [X] plc4go
• [ ] plc4c
• [ ] plc4net

Protocols

• [ ] AB-Ethernet
• [ ] ADS /AMS
• [ ] BACnet/IP
• [ ] CANopen
• [ ] DeltaV
• [ ] DF1
• [ ] EtherNet/IP
• [ ] Firmata
• [ ] KNXnet/IP
• [ ] Modbus
• [X] OPC-UA
• [ ] S7

[splatch]

Golang driver is not maintained and requires major effort to align it with java version. The encryption part for go is not implemented beyond initial handshake.

Are you sure you are using go, not python? :-)

[telmobarrena98]

Okey thanks @splatch , is plc4py working for OPC-UA? In the documentation I see that is not implemented.

[splatch]

I believe python currently covers modbus and umas, AFAIK it does not support python, but you can confirm that with @hutcheb and @ottlukas.

[hutcheb]

Yes, you are correct it isn’t implemented in plc4py.