+import asyncio
import logging
+from concurrent.futures import CancelledError
from .client import client
from .client import watcher
+from .client import connection
from .delta import get_entity_delta
log = logging.getLogger(__name__)
class ModelObserver(object):
- def __call__(self, delta, old, new, model):
+ async def __call__(self, delta, old, new, model):
if old is None and new is not None:
type_ = 'add'
else:
log.debug(
'Model changed: %s %s %s',
delta.entity, delta.type, delta.get_id())
- method(delta, old, new, model)
+ await method(delta, old, new, model)
- def on_change(self, delta, old, new, model):
+ async def on_change(self, delta, old, new, model):
pass
class Model(object):
- def __init__(self, connection):
+ def __init__(self, loop=None):
"""Instantiate a new connected Model.
- :param connection: `juju.client.connection.Connection` instance
+ :param loop: an asyncio event loop
"""
- self.connection = connection
+ self.loop = loop or asyncio.get_event_loop()
+ self.connection = None
self.observers = set()
self.state = dict()
- self._watching = False
+ self._watcher_task = None
+ self._watch_shutdown = asyncio.Event(loop=loop)
+ self._watch_received = asyncio.Event(loop=loop)
+
+ async def connect_current(self):
+ """Connect to the current Juju model.
+
+ """
+ self.connection = await connection.Connection.connect_current()
+ self._watch()
+ await self._watch_received.wait()
+
+ async def disconnect(self):
+ """Shut down the watcher task and close websockets.
+
+ """
+ self._stop_watching()
+ if self.connection and self.connection.is_open:
+ await self._watch_shutdown.wait()
+ log.debug('Closing model connection')
+ await self.connection.close()
+ self.connection = None
+
+ def all_units_idle(self):
+ """Return True if all units are idle.
+
+ """
+ for unit in self.units.values():
+ unit_status = unit.data['agent-status']['current']
+ if unit_status != 'idle':
+ return False
+ return True
+
+ async def reset(self, force=False):
+ """Reset the model to a clean state.
+
+ :param bool force: Force-terminate machines.
+
+ This returns only after the model has reached a clean state. "Clean"
+ means no applications or machines exist in the model.
+
+ """
+ for app in self.applications.values():
+ await app.destroy()
+ for machine in self.machines.values():
+ await machine.destroy(force=force)
+ await self.block_until(
+ lambda: len(self.machines) == 0
+ )
+
+ async def block_until(self, *conditions, timeout=None):
+ """Return only after all conditions are true.
+
+ """
+ async def _block():
+ while not all(c() for c in conditions):
+ await asyncio.sleep(.1)
+ await asyncio.wait_for(_block(), timeout)
@property
def applications(self):
+ """Return a map of application-name:Application for all applications
+ currently in the model.
+
+ """
return self.state.get('application', {})
+ @property
+ def machines(self):
+ """Return a map of machine-id:Machine for all machines currently in
+ the model.
+
+ """
+ return self.state.get('machine', {})
+
@property
def units(self):
- return self.state.get('unit', {})
+ """Return a map of unit-id:Unit for all units currently in
+ the model.
- def stop_watching(self):
- self.connection.cancel()
- self._watching = False
+ """
+ return self.state.get('unit', {})
def add_observer(self, callable_):
"""Register an "on-model-change" callback
Once a watch is started (Model.watch() is called), ``callable_``
will be called each time the model changes. callable_ should
- accept the following positional arguments:
+ be Awaitable and accept the following positional arguments:
delta - An instance of :class:`juju.delta.EntityDelta`
containing the raw delta data recv'd from the Juju
"""
self.observers.add(callable_)
- async def watch(self):
+ def _watch(self):
"""Start an asynchronous watch against this model.
See :meth:`add_observer` to register an onchange callback.
"""
- self._watching = True
- allwatcher = watcher.AllWatcher()
- allwatcher.connect(await self.connection.clone())
- while self._watching:
- results = await allwatcher.Next()
- for delta in results.deltas:
- delta = get_entity_delta(delta)
- old_obj, new_obj = self._apply_delta(delta)
- self._notify_observers(delta, old_obj, new_obj)
+ async def _start_watch():
+ self._watch_shutdown.clear()
+ try:
+ allwatcher = watcher.AllWatcher()
+ self._watch_conn = await self.connection.clone()
+ allwatcher.connect(self._watch_conn)
+ while True:
+ results = await allwatcher.Next()
+ for delta in results.deltas:
+ delta = get_entity_delta(delta)
+ old_obj, new_obj = self._apply_delta(delta)
+ # XXX: Might not want to shield at this level
+ # We are shielding because when the watcher is
+ # canceled (on disconnect()), we don't want all of
+ # its children (every observer callback) to be
+ # canceled with it. So we shield them. But this means
+ # they can *never* be canceled.
+ await asyncio.shield(
+ self._notify_observers(delta, old_obj, new_obj))
+ self._watch_received.set()
+ except CancelledError:
+ log.debug('Closing watcher connection')
+ await self._watch_conn.close()
+ self._watch_shutdown.set()
+ self._watch_conn = None
+
+ log.debug('Starting watcher task')
+ self._watcher_task = self.loop.create_task(_start_watch())
+
+ def _stop_watching(self):
+ """Stop the asynchronous watch against this model.
+
+ """
+ log.debug('Stopping watcher task')
+ if self._watcher_task:
+ self._watcher_task.cancel()
def _apply_delta(self, delta):
"""Apply delta to our model state and return the a copy of the
entity_class = delta.get_entity_class()
return entity_class(delta.data, self)
- def _notify_observers(self, delta, old_obj, new_obj):
+ async def _notify_observers(self, delta, old_obj, new_obj):
"""Call observing callbacks, notifying them of a change in model state
:param delta: The raw change from the watcher
"""
for o in self.observers:
- o(delta, old_obj, new_obj, self)
+ asyncio.ensure_future(o(delta, old_obj, new_obj, self))
def add_machine(
self, spec=None, constraints=None, disks=None, series=None,
pass
add_machines = add_machine
- def add_relation(self, relation1, relation2):
- """Add a relation between two services.
+ async def add_relation(self, relation1, relation2):
+ """Add a relation between two applications.
- :param str relation1: '<service>[:<relation_name>]'
- :param str relation2: '<service>[:<relation_name>]'
+ :param str relation1: '<application>[:<relation_name>]'
+ :param str relation2: '<application>[:<relation_name>]'
"""
- pass
+ app_facade = client.ApplicationFacade()
+ app_facade.connect(self.connection)
+
+ log.debug(
+ 'Adding relation %s <-> %s', relation1, relation2)
+
+ return await app_facade.AddRelation([relation1, relation2])
def add_space(self, name, *cidrs):
"""Add a new network space.
projects / osm / N2VC.git / blobdiff