Struct EventBus 

pub struct EventBus { /* private fields */ }

Event bus for broadcasting events to all subscribers.

The event bus uses a broadcast channel to deliver events to all connected receivers. Events are delivered asynchronously and in order.

WARNING: Synchronous subscribers (SubscriberRegistry) are shared across clones. Storing a cloned EventBus inside a synchronous subscriber will create a memory leak via an Arc reference cycle. If a synchronous subscriber needs to publish events, store a std::sync::Weak<EventBus> or communicate via a separate channel.

Implementations

impl EventBus

pub fn new() -> Self

Create a new event bus with default capacity.

pub fn with_capacity(capacity: usize) -> Self

Create a new event bus with specified capacity.

pub fn publish(&self, event: AstridEvent) -> usize

Publish an event to all subscribers.

This method broadcasts the event to all async subscribers and notifies all synchronous subscribers in the registry.

Returns the number of async receivers that received the event.

pub fn subscribe(&self) -> EventReceiver

Subscribe to events.

Returns a receiver that will receive all published events. The receiver’s lag is attributed to the "untagged" subscriber in [METRIC_BUS_RECEIVER_LAGGED_TOTAL]; use subscribe_as to give a long-lived consumer a stable label.

pub fn subscribe_as(&self, subscriber: &'static str) -> EventReceiver

Subscribe to all events, attributing this receiver’s lag to a stable subscriber label. Pass a fixed &'static str (never caller/remote text) so the lag-counter cardinality stays bounded.

pub fn subscribe_topic(&self, topic_pattern: impl Into<String>) -> EventReceiver

Subscribe to IPC events matching a specific topic pattern.

The pattern can be an exact match (e.g. astrid.cli.input) or end with a trailing * (e.g. astrid.v1.request.*) which matches one or more remaining dot-separated segments up to a maximum depth of 20. Middle wildcards (e.g. astrid.*.event) match exactly one segment.

Lag is attributed to "untagged"; use subscribe_topic_as for a long-lived consumer.

pub fn subscribe_topic_as( &self, topic_pattern: impl Into<String>, subscriber: &'static str, ) -> EventReceiver

Topic subscription that attributes this receiver’s lag to a stable subscriber label. Pass a fixed &'static str (never the topic pattern itself, which can be capsule-supplied) so the lag-counter cardinality stays bounded.

pub fn subscribe_topic_routed( &self, capsule_uuid: Uuid, topic_pattern: impl Into<String>, capsule_id_label: impl Into<String>, subscriber: &'static str, ) -> RoutedEventReceiver

Subscribe with publish-side per-(capsule, topic, principal) routing.

Allocates a [RouteEntry] in the bus’s routes table and returns a RoutedEventReceiver that drains its own queues with deficit-round-robin fairness across principals. Two receivers of the same (capsule_uuid, topic_pattern) get distinct routes — each receives its own copy of every matching event, unlike the broadcast channel which shares one queue.

Dropping the receiver removes its route from the bus.

pub fn subscribe_topic_routed_scoped( &self, capsule_uuid: Uuid, topic_pattern: impl Into<String>, capsule_id_label: impl Into<String>, subscriber: &'static str, scope: Option<PrincipalKey>, ) -> RoutedEventReceiver

Routed subscription self-scoped to a single publisher principal.

Identical to subscribe_topic_routed except the route only ever admits events whose publisher PrincipalKey equals scope; foreign-principal events are dropped at enqueue so they never enter this route’s byte budget (see RouteEntry::accepts). Pass scope == None for the unscoped, all-principals behaviour — subscribe_topic_routed is exactly that delegation.

The scope is the authorization seam for capability-gated firehose topics (e.g. the audit feed): a non-privileged subscriber is scoped to its own principal so it can never observe another principal’s events, while a privileged firehose holder subscribes with scope == None.

Dropping the receiver removes its route from the bus.

pub fn routed_subscription_count(&self) -> usize

Number of active routed subscriptions (diagnostic).

pub fn subscriber_count(&self) -> usize

Get the current number of active subscribers (both async and synchronous).

pub fn capacity(&self) -> usize

Get the channel capacity.

Trait Implementations

impl Clone for EventBus

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for EventBus

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for EventBus

fn default() -> Self

Returns the “default value” for a type.