+"""
+This example:
+
+1. Connects to the current model
+2. Resets it
+3. Deploys two charms and relates them
+4. Waits for units to be idle, then exits
+
+"""
+import asyncio
+import logging
+
+from juju.model import Model, ModelObserver
+from juju import loop
+
+
+class MyRemoveObserver(ModelObserver):
+ async def on_change(self, delta, old, new, model):
+ if delta.type == 'remove':
+ assert(new.latest() == new)
+ assert(new.next() is None)
+ assert(new.dead)
+ assert(new.current)
+ assert(new.connected)
+ assert(new.previous().dead)
+ assert(not new.previous().current)
+ assert(not new.previous().connected)
+
+
+class MyModelObserver(ModelObserver):
+ _shutting_down = False
+
+ async def on_change(self, delta, old, new, model):
+ if model.units and model.all_units_idle() and not self._shutting_down:
+ self._shutting_down = True
+ logging.debug('All units idle, disconnecting')
+ await model.reset(force=True)
+ await model.disconnect()
+
+
+async def main():
+ model = Model()
+ await model.connect_current()
+
+ model.add_observer(MyRemoveObserver())
+ await model.reset(force=True)
+ model.add_observer(MyModelObserver())
+
+ ubuntu_app = await model.deploy(
+ 'ubuntu',
+ application_name='ubuntu',
+ series='trusty',
+ channel='stable',
+ )
+ ubuntu_app.on_change(asyncio.coroutine(
+ lambda delta, old_app, new_app, model:
+ print('App changed: {}'.format(new_app.entity_id))
+ ))
+ ubuntu_app.on_remove(asyncio.coroutine(
+ lambda delta, old_app, new_app, model:
+ print('App removed: {}'.format(old_app.entity_id))
+ ))
+ ubuntu_app.on_unit_add(asyncio.coroutine(
+ lambda delta, old_unit, new_unit, model:
+ print('Unit added: {}'.format(new_unit.entity_id))
+ ))
+ ubuntu_app.on_unit_remove(asyncio.coroutine(
+ lambda delta, old_unit, new_unit, model:
+ print('Unit removed: {}'.format(old_unit.entity_id))
+ ))
+ unit_a, unit_b = await ubuntu_app.add_units(count=2)
+ unit_a.on_change(asyncio.coroutine(
+ lambda delta, old_unit, new_unit, model:
+ print('Unit changed: {}'.format(new_unit.entity_id))
+ ))
+ await model.deploy(
+ 'nrpe',
+ application_name='nrpe',
+ series='trusty',
+ channel='stable',
+ # subordinates must be deployed without units
+ num_units=0,
+ )
+ my_relation = await model.add_relation(
+ 'ubuntu',
+ 'nrpe',
+ )
+ my_relation.on_remove(asyncio.coroutine(
+ lambda delta, old_rel, new_rel, model:
+ print('Relation removed: {}'.format(old_rel.endpoints))
+ ))
+
+
+if __name__ == '__main__':
+ logging.basicConfig(level=logging.DEBUG)
+ ws_logger = logging.getLogger('websockets.protocol')
+ ws_logger.setLevel(logging.INFO)
+ loop.run(main())