Observability Event Bus¶

Runtime observability uses victor.core.events.ObservabilityBus. Its events are
MessagingEvent objects with a string topic and a data mapping. Subscriptions and
emission are asynchronous. The removed victor.observability.event_bus module and its
EventCategory enum are not current APIs.

This example owns a bus for its lifetime and unregisters the subscription on exit.
Topic patterns such as metric.* match related events.

import asyncio
from victor.core.events import MessagingEvent, ObservabilityBus

async def main():
    bus = ObservabilityBus()
    await bus.connect()

    received = asyncio.Event()

    async def on_metric(event: MessagingEvent):
        print(event.topic, event.data)
        received.set()

    handle = await bus.subscribe("metric.*", on_metric)
    try:
        await bus.emit("metric.latency", {"value": 42.5}, source="example")
        await asyncio.wait_for(received.wait(), timeout=1.0)
    finally:
        await bus.unsubscribe(handle)
        await bus.disconnect()

asyncio.run(main())

Shared application bus¶

Runtime integrations can obtain the configured bus with get_observability_bus()
from victor.core.events. The application owns that shared bus's lifetime: remove
your subscription when finished, and let the application manage connection shutdown.
Handlers receive MessagingEvent, not the removed event category/priority structure.

Delivery and failure behavior¶

Observability emission uses AT_MOST_ONCE delivery. emit() returns a boolean and
handles EventPublishError as an observability failure rather than crashing the
application. It is not a durable task queue. Reliable agent communication has a separate
AgentMessageBus; backend capabilities determine delivery guarantees.

Agent streams and exporters¶

Agent.stream() emits framework events (EventType), a separate surface intended
for application consumers. See Python API.
For event logging and the dashboard, see metrics. Exporters subscribe
to runtime topics; do not use an EventCategory filter copied from older examples.

Architecture¶

The event-bus boundary guide explains how
framework streams, instrumentation, and messaging relate. The earlier category-based
bus guide is retained in page history.

Event backends¶

The event backends diagram separates telemetry, messaging, and protocol adapters.