modules/libjuju/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()
  44
  45     try:
  46         model.add_observer(MyRemoveObserver())
  47         await model.reset(force=True)
  48         model.add_observer(MyModelObserver())
  49
  50         ubuntu_app = await model.deploy(
  51             'ubuntu',
  52             application_name='ubuntu',
  53             series='trusty',
  54             channel='stable',
  55         )
  56         ubuntu_app.on_change(asyncio.coroutine(
  57             lambda delta, old_app, new_app, model:
  58                 print('App changed: {}'.format(new_app.entity_id))
  59         ))
  60         ubuntu_app.on_remove(asyncio.coroutine(
  61             lambda delta, old_app, new_app, model:
  62                 print('App removed: {}'.format(old_app.entity_id))
  63         ))
  64         ubuntu_app.on_unit_add(asyncio.coroutine(
  65             lambda delta, old_unit, new_unit, model:
  66                 print('Unit added: {}'.format(new_unit.entity_id))
  67         ))
  68         ubuntu_app.on_unit_remove(asyncio.coroutine(
  69             lambda delta, old_unit, new_unit, model:
  70                 print('Unit removed: {}'.format(old_unit.entity_id))
  71         ))
  72         unit_a, unit_b = await ubuntu_app.add_units(count=2)
  73         unit_a.on_change(asyncio.coroutine(
  74             lambda delta, old_unit, new_unit, model:
  75                 print('Unit changed: {}'.format(new_unit.entity_id))
  76         ))
  77         await model.deploy(
  78             'nrpe',
  79             application_name='nrpe',
  80             series='trusty',
  81             channel='stable',
  82             # subordinates must be deployed without units
  83             num_units=0,
  84         )
  85         my_relation = await model.add_relation(
  86             'ubuntu',
  87             'nrpe',
  88         )
  89         my_relation.on_remove(asyncio.coroutine(
  90             lambda delta, old_rel, new_rel, model:
  91                 print('Relation removed: {}'.format(old_rel.endpoints))
  92         ))
  93     finally:
  94         await model.disconnect()
  95
  96
  97 if __name__ == '__main__':
  98     logging.basicConfig(level=logging.INFO)
  99     ws_logger = logging.getLogger('websockets.protocol')
 100     ws_logger.setLevel(logging.INFO)
 101     loop.run(main())