How to use the ops.framework.EventSource function in ops
To help you get started, we’ve selected a few ops examples, based on popular ways it is used in public projects.
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canonical / operator / test / test_framework.py View on Github 
def test_defer_and_reemit(self):
framework = self.create_framework()
class MyEvent(EventBase):
pass
class MyNotifier1(Object):
a = EventSource(MyEvent)
b = EventSource(MyEvent)
class MyNotifier2(Object):
c = EventSource(MyEvent)
class MyObserver(Object):
def __init__(self, parent, key):
super().__init__(parent, key)
self.seen = []
self.done = {}
def on_any(self, event):
self.seen.append(event.handle.kind)
if not self.done.get(event.handle.kind):
event.defer()
pub1 = MyNotifier1(framework, "1")
pub2 = MyNotifier2(framework, "1")
obs1 = MyObserver(framework, "1")
obs2 = MyObserver(framework, "2")def test_defer_and_reemit(self):
framework = self.create_framework()
class MyEvent(EventBase):
pass
class MyNotifier1(Object):
a = EventSource(MyEvent)
b = EventSource(MyEvent)
class MyNotifier2(Object):
c = EventSource(MyEvent)
class MyObserver(Object):
def __init__(self, parent, key):
super().__init__(parent, key)
self.seen = []
self.done = {}
def on_any(self, event):
self.seen.append(event.handle.kind)
if not self.done.get(event.handle.kind):
event.defer()framework = self.create_framework()
class MyEvent(EventBase):
def __init__(self, handle, n):
super().__init__(handle)
self.my_n = n
def snapshot(self):
return {"My N!": self.my_n}
def restore(self, snapshot):
super().restore(snapshot)
self.my_n = snapshot["My N!"] + 1
class MyNotifier(Object):
foo = EventSource(MyEvent)
class MyObserver(Object):
def __init__(self, parent, key):
super().__init__(parent, key)
self.seen = []
def _on_foo(self, event):
self.seen.append("on_foo:{}={}".format(event.handle.kind, event.my_n))
event.defer()
pub = MyNotifier(framework, "1")
obs = MyObserver(framework, "1")
framework.observe(pub.foo, obs._on_foo)
pub.foo.emit(1)def test_weak_observer(self):
framework = self.create_framework()
observed_events = []
class MyEvent(EventBase):
pass
class MyEvents(ObjectEvents):
foo = EventSource(MyEvent)
class MyNotifier(Object):
on = MyEvents()
class MyObserver(Object):
def _on_foo(self, event):
observed_events.append("foo")
pub = MyNotifier(framework, "1")
obs = MyObserver(framework, "2")
framework.observe(pub.on.foo, obs._on_foo)
pub.on.foo.emit()
self.assertEqual(observed_events, ["foo"])
# Now delete the observer, and note that when we emit the event, it
# doesn't update the local slice againos.environ.clear()
os.environ.update(env)
self.addCleanup(restore_env, os.environ.copy())
os.environ['PATH'] = "{}:{}".format(Path(__file__).parent / 'bin', os.environ['PATH'])
os.environ['JUJU_UNIT_NAME'] = 'local/0'
self.tmpdir = Path(tempfile.mkdtemp())
self.addCleanup(shutil.rmtree, str(self.tmpdir))
self.meta = CharmMeta()
class CustomEvent(EventBase):
pass
class TestCharmEvents(CharmEvents):
custom = EventSource(CustomEvent)
# Relations events are defined dynamically and modify the class attributes.
# We use a subclass temporarily to prevent these side effects from leaking.
CharmBase.on = TestCharmEvents()
def cleanup():
CharmBase.on = CharmEvents()
self.addCleanup(cleanup)def test_bad_sig_observer(self):
class MyEvent(EventBase):
pass
class MyNotifier(Object):
foo = EventSource(MyEvent)
bar = EventSource(MyEvent)
baz = EventSource(MyEvent)
qux = EventSource(MyEvent)
class MyObserver(Object):
def _on_foo(self):
assert False, 'should not be reached'
def _on_bar(self, event, extra):
assert False, 'should not be reached'
def _on_baz(self, event, extra=None, *, k):
assert False, 'should not be reached'
def _on_qux(self, event, extra=None):
assert False, 'should not be reached'Called when new storage is available for the charm to use.
"""
class StorageDetachingEvent(StorageEvent):
"""Represents the `storage-detaching` hook from Juju.
Called when storage a charm has been using is going away.
"""
class CharmEvents(ObjectEvents):
"""The events that are generated by Juju in response to the lifecycle of an application."""
install = EventSource(InstallEvent)
start = EventSource(StartEvent)
stop = EventSource(StopEvent)
remove = EventSource(RemoveEvent)
update_status = EventSource(UpdateStatusEvent)
config_changed = EventSource(ConfigChangedEvent)
upgrade_charm = EventSource(UpgradeCharmEvent)
pre_series_upgrade = EventSource(PreSeriesUpgradeEvent)
post_series_upgrade = EventSource(PostSeriesUpgradeEvent)
leader_elected = EventSource(LeaderElectedEvent)
leader_settings_changed = EventSource(LeaderSettingsChangedEvent)
collect_metrics = EventSource(CollectMetricsEvent)
class CharmBase(Object):
"""Base class that represents the Charm overall.
Usually this initialization is done by ops.main.main() rather than Charm authorsclass StorageDetachingEvent(StorageEvent):
"""Represents the `storage-detaching` hook from Juju.
Called when storage a charm has been using is going away.
"""
class CharmEvents(ObjectEvents):
"""The events that are generated by Juju in response to the lifecycle of an application."""
install = EventSource(InstallEvent)
start = EventSource(StartEvent)
stop = EventSource(StopEvent)
remove = EventSource(RemoveEvent)
update_status = EventSource(UpdateStatusEvent)
config_changed = EventSource(ConfigChangedEvent)
upgrade_charm = EventSource(UpgradeCharmEvent)
pre_series_upgrade = EventSource(PreSeriesUpgradeEvent)
post_series_upgrade = EventSource(PostSeriesUpgradeEvent)
leader_elected = EventSource(LeaderElectedEvent)
leader_settings_changed = EventSource(LeaderSettingsChangedEvent)
collect_metrics = EventSource(CollectMetricsEvent)
class CharmBase(Object):
"""Base class that represents the Charm overall.
Usually this initialization is done by ops.main.main() rather than Charm authors
directly instantiating a Charm.
"""
class StorageDetachingEvent(StorageEvent):
"""Represents the `storage-detaching` hook from Juju.
Called when storage a charm has been using is going away.
"""
class CharmEvents(ObjectEvents):
"""The events that are generated by Juju in response to the lifecycle of an application."""
install = EventSource(InstallEvent)
start = EventSource(StartEvent)
stop = EventSource(StopEvent)
remove = EventSource(RemoveEvent)
update_status = EventSource(UpdateStatusEvent)
config_changed = EventSource(ConfigChangedEvent)
upgrade_charm = EventSource(UpgradeCharmEvent)
pre_series_upgrade = EventSource(PreSeriesUpgradeEvent)
post_series_upgrade = EventSource(PostSeriesUpgradeEvent)
leader_elected = EventSource(LeaderElectedEvent)
leader_settings_changed = EventSource(LeaderSettingsChangedEvent)
collect_metrics = EventSource(CollectMetricsEvent)
class CharmBase(Object):
"""Base class that represents the Charm overall.
Usually this initialization is done by ops.main.main() rather than Charm authors
directly instantiating a Charm.Called when storage a charm has been using is going away.
"""
class CharmEvents(ObjectEvents):
"""The events that are generated by Juju in response to the lifecycle of an application."""
install = EventSource(InstallEvent)
start = EventSource(StartEvent)
stop = EventSource(StopEvent)
remove = EventSource(RemoveEvent)
update_status = EventSource(UpdateStatusEvent)
config_changed = EventSource(ConfigChangedEvent)
upgrade_charm = EventSource(UpgradeCharmEvent)
pre_series_upgrade = EventSource(PreSeriesUpgradeEvent)
post_series_upgrade = EventSource(PostSeriesUpgradeEvent)
leader_elected = EventSource(LeaderElectedEvent)
leader_settings_changed = EventSource(LeaderSettingsChangedEvent)
collect_metrics = EventSource(CollectMetricsEvent)
class CharmBase(Object):
"""Base class that represents the Charm overall.
Usually this initialization is done by ops.main.main() rather than Charm authors
directly instantiating a Charm.
Args:
framework: The framework responsible for managing the Model and events for this
Charm.
key: Ignored; will remove after deprecation period of the signature change.
