EventDependency

class safir.dependencies.metrics.EventDependency(event_maker)

Bases: Generic[E]

Provides EventManager-managed events for apps to publish.

Parameters:

event_maker (TypeVar(E, bound= EventMaker)) – An instance of an implementation of EventMaker

Examples

myapp.dependencies.events_dependency

from safir.metrics import (
    EventMaker,
    EventManager,
    EventPayload,
    EventsDependency,
    MetricsConfigurationWithKafka,
)

class Event1(EventPayload):
    foo: str
    bar: str


class event2(EventPayload):
    baz: int
    buz: str


class Events(EventMaker):
    async def initialize(self, manager: EventManager) -> None:
        self.event1 = await manager.create_publisher("event1", Event1)
        self.event2 = await manager.create_publisher("event2", Event2)


dependency = EventsDependency(AppEvents())

myapp.main

from myapp.dependencies.events_dependency import dependency as ed

# In application init, maybe a lifecycle method in a FastAPI app
manager = MetricsConfigurationWithKafka().make_manager()
await manager.initialize()
await events.initialize(manager)

myapp.someservice

from myapp.dependencies.events_dependency import dependency as ed


events = ed()

# In app code
await events.event1.publish(Event1(foo="foo", bar="bar"))
await events.event2.publish(Event2(baz=123, buz="buz"))

Attributes Summary

events

Return the instantiated event maker.

Methods Summary

__call__()	Return the initialized event maker for use as a FastAPI dependency.
initialize(manager)	Initialize the event maker and set the attribute.

Attributes Documentation

events

Return the instantiated event maker.

Raises:

RuntimeError – If this EventsDependency hasn’t been intialized yet.

Methods Documentation

async __call__()

Return the initialized event maker for use as a FastAPI dependency.

Return type:

TypeVar(E, bound= EventMaker)

async initialize(manager)

Initialize the event maker and set the attribute.

Parameters:

manager (EventManager) – An EventManager to register and publish events.

Return type:

None