chore: events as OTEL events; wip custom events

dont-merge/fake-charm.py

@@ -25,6 +25,31 @@
 tracer = opentelemetry.trace.get_tracer(__name__)
 
 
+class DatabaseReadyEvent(ops.charm.EventBase):
+    """Event representing that the database is ready."""
+
+
+class DatabaseRequirerEvents(ops.framework.ObjectEvents):
+    """Container for Database Requirer events."""
+
+    ready = ops.charm.EventSource(DatabaseReadyEvent)
+
+
+class DatabaseRequirer(ops.framework.Object):
+    """Dummy docstring."""
+
+    on = DatabaseRequirerEvents()  # type: ignore
+
+    def __init__(self, charm: ops.CharmBase):
+        """Dummy docstring."""
+        super().__init__(charm, 'foo')
+        self.framework.observe(charm.on.start, self._on_db_changed)
+
+    def _on_db_changed(self, event: ops.StartEvent) -> None:
+        """Dummy docstring."""
+        self.on.ready.emit()
+
+
 class FakeCharm(ops.CharmBase):
     """Dummy docstring."""
 
@@ -33,13 +58,17 @@ def __init__(self, framework: ops.Framework):
         super().__init__(framework)
         self.framework.observe(self.on.start, self._on_start)
         self.framework.observe(self.on.collect_app_status, self._on_collect_app_status)
-        self.framework.observe(self.on.collect_unit_status, self._on_collect_unit_status)
+        self.db_requirer = DatabaseRequirer(self)
+        self.framework.observe(self.db_requirer.on.ready, self._on_db_ready)
 
     def _on_start(self, event: ops.StartEvent) -> None:
         """Dummy docstring."""
         ops.set_tracing_destination(url='http://localhost:4318/v1/traces')
         self.dummy_load(event, 0.0025)
 
+    def _on_db_ready(self, event: DatabaseReadyEvent) -> None:
+        self.dummy_load(event, 0.001)
+
     def _on_collect_app_status(self, event: ops.CollectStatusEvent) -> None:
         """Dummy docstring."""
         self.dummy_load(event)

ops/charm.py

@@ -1333,8 +1333,6 @@ def __init__(self, framework: ops.Framework):
         @property
         def on(self) -> CharmEvents: ...  # noqa
 
-    # FIXME not sure if this is needed
-    # may help to exclude `super().__init__(...)` from `UserCharm.__init__`
     @tracer.start_as_current_span('ops.CharmBase')  # type: ignore
     def __init__(self, framework: Framework):
         super().__init__(framework, None)
@@ -1391,8 +1389,6 @@ def config(self) -> model.ConfigData:
         return self.model.config
 
 
-# FIXME may or may not be useful
-@tracer.start_as_current_span('ops.charm._evaluate_status')  # type: ignore
 def _evaluate_status(charm: CharmBase):  # pyright: ignore[reportUnusedFunction]
     """Trigger collect-status events and evaluate and set the highest-priority status.
 
@@ -1565,7 +1561,6 @@ def __init__(
         }
 
     @staticmethod
-    @tracer.start_as_current_span('ops.CharmMeta.from_charm_root')  # type: ignore
     def from_charm_root(charm_root: Union[pathlib.Path, str]):
         """Initialise CharmMeta from the path to a charm repository root folder."""
         _charm_root = pathlib.Path(charm_root)
@@ -1925,8 +1920,6 @@ class ContainerMeta:
     resource is specified.
     """
 
-    # FIXME is this ever needed? maybe if there are really many mounts?
-    @tracer.start_as_current_span('ops.ContainerMeta')  # type: ignore
     def __init__(self, name: str, raw: Dict[str, Any]):
         self.name = name
         self._mounts: Dict[str, ContainerStorageMeta] = {}

ops/framework.py

@@ -603,7 +603,6 @@ class Framework(Object):
         @property
         def on(self) -> 'FrameworkEvents': ...  # noqa
 
-    @tracer.start_as_current_span('ops.Framework')  # type: ignore
     def __init__(
         self,
         storage: Union[SQLiteStorage, JujuStorage],
@@ -697,7 +696,6 @@ def _forget(self, obj: 'Serializable'):
         """Stop tracking the given object. See also _track."""
         self._objects.pop(obj.handle.path, None)
 
-    @tracer.start_as_current_span('ops.Framework.commit')  # type: ignore
     def commit(self) -> None:
         """Save changes to the underlying backends."""
         # Give a chance for objects to persist data they want to before a commit is made.
@@ -871,12 +869,16 @@ def _event_is_in_storage(
                 return True
         return False
 
-    @tracer.start_as_current_span('ops.Framework._emit')  # type: ignore
     def _emit(self, event: EventBase):
         """See BoundEvent.emit for the public way to call this."""
         saved = False
         event_path = event.handle.path
         event_kind = event.handle.kind
+        ops_event = event.__class__.__module__.startswith('ops.')
+        opentelemetry.trace.get_current_span().add_event(
+            f'{"ops." if ops_event else ""}{event.__class__.__name__}',
+            attributes={'deferred': event.deferred, 'kind': event_kind},
+        )
         parent = event.handle.parent
         assert isinstance(parent, Handle), 'event handle must have a parent'
         parent_path = parent.path
@@ -913,7 +915,6 @@ def _emit(self, event: EventBase):
         if saved:
             self._reemit(event_path)
 
-    @tracer.start_as_current_span('ops.Framework.reemit')  # type: ignore
     def reemit(self) -> None:
         """Reemit previously deferred events to the observers that deferred them.