A Python library for Juju

Source code: https://github.com/juju/python-libjuju

Bug reports: https://github.com/juju/python-libjuju/issues

Documentation: https://pythonlibjuju.readthedocs.io/en/latest/

Requirements

• Python 3.9/3.10

Design Notes

• Asynchronous - Uses asyncio and async/await features of Python
• Websocket-level bindings are programmatically generated (indirectly) from the Juju golang code, ensuring full api coverage
• Provides an OO layer which encapsulates much of the websocket api and provides familiar nouns and verbs (e.g. Model.deploy(), Application.add_unit(), etc.)

Installation

pip3 install juju

Quickstart

Here's a simple example that shows basic usage of the library. The example connects to the currently active Juju model, deploys a single unit of the ubuntu charm, then exits:

#!/usr/bin/python3

import logging
import sys

from juju import asyncio
from juju.model import Model


async def deploy():
    # Create a Model instance. We need to connect our Model to a Juju api
    # server before we can use it.
    model = Model()

    # Connect to the currently active Juju model
    await model.connect()

    try:
        # Deploy a single unit of the ubuntu charm, using the latest revision
        # from the stable channel of the Charm Store.
        ubuntu_app = await model.deploy(
          'ubuntu',
          application_name='ubuntu',
        )

        if '--wait' in sys.argv:
            # optionally block until the application is ready
            await model.wait_for_idle(status = 'active')

    finally:
        # Disconnect from the api server and cleanup.
        await model.disconnect()


def main():
    logging.basicConfig(level=logging.INFO)

    # If you want to see everything sent over the wire, set this to DEBUG.
    ws_logger = logging.getLogger('websockets.protocol')
    ws_logger.setLevel(logging.INFO)

    # Run the deploy coroutine in an asyncio event loop, using a helper
    # that abstracts loop creation and teardown.
    asyncio.run(deploy())


if __name__ == '__main__':
    main()

More examples can be found in the docs, as well as in the examples/ directory of the source tree which can be run using tox. For example, to run examples/connect_current_model.py, use:

tox -e example -- examples/connect_current_model.py

REPL

To experiment with the library in a REPL, launch python in asyncio mode

$ python3 -m asyncio

and then, to connect to the current model and fetch status:

>>> from juju.model import Model
>>> model = Model()
>>> await model.connect_current()
>>> status = await model.get_status()

Versioning

Pylibjuju releases now track the Juju release cadence. New generated schemas will be updated per Juju releases.