asyncua

library2.0.1pypypi✓ verified 23d ago

asyncua is a comprehensive, pure Python library providing both OPC-UA client and server capabilities, designed for asynchronous operations. It enables Python applications to communicate with industrial automation systems using the OPC-UA protocol. Currently at version 1.1.8, the library maintains an active development pace, with frequent bug fixes and feature enhancements, including recent beta releases for upcoming major versions.

http-networking workflow

pip install asyncua

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · ASYNCUA

asyncua

http-networkingpythonv2.0.1

Install

4.8s avg

Import

1785ms

Disk

74MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v2.0.1 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.910 runs

installs and imports cleanly · install 0.0s · import 1.861s · 72MB

glibc

py 3.10–3.910 runs

installs and imports cleanly · install 4.8s · import 1.709s · 72MB

74MB installed

● package 74MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Client

✓ from asyncua import Client

Server

✓ from asyncua import Server

✓ from asyncua import ua

✗ import asyncua.ua

Import `ua` directly for convenient access to OPC-UA data types like Variant, NodeId, etc.

Node

✓ from asyncua.common.node import Node

While Node objects are common, they are usually obtained from Client/Server methods rather than instantiated directly. Direct import is for type hinting or advanced scenarios.

This quickstart demonstrates how to establish a basic OPC-UA client connection, retrieve the root node, and gracefully disconnect. It uses an environment variable for the server URL, which is a common practice for flexible deployment. Remember that `asyncua` is built on `asyncio`, so all client/server operations must be `await`ed within an `async` function.

import asyncio from asyncua import Client, ua import os async def main(): # Replace with your OPC-UA server endpoint server_url = os.environ.get('OPCUA_SERVER_URL', 'opc.tcp://localhost:4840/freeopcua/server/') # Client connection example client = Client(url=server_url) try: await client.connect() print(f"Connected to OPC-UA server at {server_url}") # Get the root node root = client.get_root_node() print(f"Root node: {root}") # Example: Read a variable (replace with actual node ID) # For example, to read a variable under Objects/MyObject/MyVariable # node_id_str = "ns=2;i=1001" # Example NodeId # my_variable = await client.get_node(node_id_str) # value = await my_variable.read_value() # print(f"Value of {node_id_str}: {value}") # You can browse nodes, subscribe to data changes, write values, etc. except Exception as e: print(f"Error connecting or interacting with server: {e}") finally: print("Disconnecting from OPC-UA server...") await client.disconnect() if __name__ == '__main__': asyncio.run(main())

Debug

Known issues

breakingStarting with version 1.2.0 (currently in beta), asyncua removes support for Python versions older than 3.10. Users on Python 3.9 or earlier must upgrade their Python environment before migrating to asyncua 1.2.x or later.

fix

Upgrade your Python environment to 3.10 or newer. For projects requiring older Python versions, stick to asyncua version 1.1.x or earlier.

affects: >=1.2.0

gotchaasyncua is an asyncio-based library. All network operations (connect, read, write, subscribe, disconnect, etc.) are coroutines and must be properly `await`ed within an `async` function. Forgetting `await` will result in coroutine objects not being run, leading to unexpected behavior or resource leaks.

fix

Ensure all asyncua methods are called with `await`. For example, use `await client.connect()` instead of `client.connect()`.

affects: All

gotchaAlways ensure to call `await client.disconnect()` or use `async with Client(...)` for client connections to gracefully close the connection and release resources. Failing to do so can leave dangling connections and consume system resources unnecessarily.

fix

Wrap client connection logic in `try...finally` to ensure `await client.disconnect()` is called, or preferably, use `async with Client(...) as client:` which handles connection and disconnection automatically.

affects: All

gotchaWhen interacting with OPC-UA values, ensure correct handling of `asyncua.ua.Variant` and `asyncua.ua.VariantType`. Directly assigning Python types might work for simple cases, but explicit `ua.Variant` usage is often required for specific OPC-UA data types, especially when writing values.

fix

When writing values, explicitly construct `ua.Variant` objects with the correct `VariantType` if the default conversion is not sufficient, e.g., `await node.write_value(ua.Variant(123, ua.VariantType.Int32))`.

affects: All

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'asyncua'

The 'asyncua' module is not installed in the Python environment.

fix

Install the module using pip: 'pip install asyncua'.

ModuleNotFoundError: No module named 'asyncio'

The 'asyncio' module is not installed in the Python environment.

fix

Install the module using pip: 'pip install asyncio'.

ModuleNotFoundError: No module named 'pyee.asyncio'

The 'pyee.asyncio' module is not installed in the Python environment.

fix

Install the module using pip: 'pip install pyee'.

ModuleNotFoundError: No module named 'pyserial-asyncio'

The 'pyserial-asyncio' module is not installed in the Python environment.

fix

Install the module using pip: 'pip install pyserial-asyncio'.

ModuleNotFoundError: No module named 'nest-asyncio'

The 'nest-asyncio' module is not installed in the Python environment.

fix

Install the module using pip: 'pip install nest-asyncio'.

Upgrade

Version history

2.0.1latest on PyPI · released Jun 29, 2026

Audit

Dependencies

No dependency data recorded yet.

Agent activity

102 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/FreeOpcUa/opcua-asyncio ↗

packagehttps://pypi.org/project/asyncua/ ↗

homepagehttp://freeopcua.github.io/ ↗