examples/relate.py

   1 """
   2 This example:
   3
   4 1. Connects to the current model
   5 2. Resets it
   6 3. Deploys two charms and relates them
   7 4. Waits for units to be idle, then exits
   8
   9 """
  10 import asyncio
  11 import logging
  12
  13 from juju.model import Model, ModelObserver
  14 from juju import loop
  15
  16
  17 class MyRemoveObserver(ModelObserver):
  18     async def on_change(self, delta, old, new, model):
  19         if delta.type == 'remove':
  20             assert(new.latest() == new)
  21             assert(new.next() is None)
  22             assert(new.dead)
  23             assert(new.current)
  24             assert(new.connected)
  25             assert(new.previous().dead)
  26             assert(not new.previous().current)
  27             assert(not new.previous().connected)
  28
  29
  30 class MyModelObserver(ModelObserver):
  31     _shutting_down = False
  32
  33     async def on_change(self, delta, old, new, model):
  34         if model.units and model.all_units_idle() and not self._shutting_down:
  35             self._shutting_down = True
  36             logging.debug('All units idle, disconnecting')
  37             await model.reset(force=True)
  38             await model.disconnect()
  39
  40
  41 async def main():
  42     model = Model()
  43     await model.connect_current()
  44
  45     model.add_observer(MyRemoveObserver())
  46     await model.reset(force=True)
  47     model.add_observer(MyModelObserver())
  48
  49     ubuntu_app = await model.deploy(
  50         'ubuntu',
  51         application_name='ubuntu',
  52         series='trusty',
  53         channel='stable',
  54     )
  55     ubuntu_app.on_change(asyncio.coroutine(
  56         lambda delta, old_app, new_app, model:
  57             print('App changed: {}'.format(new_app.entity_id))
  58     ))
  59     ubuntu_app.on_remove(asyncio.coroutine(
  60         lambda delta, old_app, new_app, model:
  61             print('App removed: {}'.format(old_app.entity_id))
  62     ))
  63     ubuntu_app.on_unit_add(asyncio.coroutine(
  64         lambda delta, old_unit, new_unit, model:
  65             print('Unit added: {}'.format(new_unit.entity_id))
  66     ))
  67     ubuntu_app.on_unit_remove(asyncio.coroutine(
  68         lambda delta, old_unit, new_unit, model:
  69             print('Unit removed: {}'.format(old_unit.entity_id))
  70     ))
  71     unit_a, unit_b = await ubuntu_app.add_units(count=2)
  72     unit_a.on_change(asyncio.coroutine(
  73         lambda delta, old_unit, new_unit, model:
  74             print('Unit changed: {}'.format(new_unit.entity_id))
  75     ))
  76     await model.deploy(
  77         'nrpe',
  78         application_name='nrpe',
  79         series='trusty',
  80         channel='stable',
  81         # subordinates must be deployed without units
  82         num_units=0,
  83     )
  84     my_relation = await model.add_relation(
  85         'ubuntu',
  86         'nrpe',
  87     )
  88     my_relation.on_remove(asyncio.coroutine(
  89         lambda delta, old_rel, new_rel, model:
  90             print('Relation removed: {}'.format(old_rel.endpoints))
  91     ))
  92
  93
  94 if __name__ == '__main__':
  95     logging.basicConfig(level=logging.DEBUG)
  96     ws_logger = logging.getLogger('websockets.protocol')
  97     ws_logger.setLevel(logging.INFO)
  98     loop.run(main())