#!/usr/bin/python3.5

import asyncio
import logging

from juju import loop
from juju.model import Model, ModelObserver

class ModelWatcher(ModelObserver):

    async def on_machine_add(self, delta, old, new, model):
        self._print("ADD", delta.data)

    async def on_machine_change(self, delta, old, new, model):
        self._print("CHANGE", delta.data)

    def _print(self, label, data):
        machine_id = data["id"]
        status = data.get("instance-status", {})
        print("machine {} {}: {} ({})".format(
            machine_id,
            label,
            status["current"],
            status["message"]))


async def setup():
    model = Model()
    await model.connect_current()
    model.add_observer(ModelWatcher())

logging.basicConfig(level=logging.WARNING)
loop = asyncio.get_event_loop()
loop.run_until_complete(setup())
loop.run_forever()