Struct NetworkEventBus 

pub struct NetworkEventBus {
    pub config: EventBusConfig,
    pub subscriptions: HashMap<u64, NebSubscription>,
    pub replay_buffer: VecDeque<NebNetworkEvent>,
    pub next_event_id: u64,
    pub next_sub_id: u64,
    pub total_published: u64,
    pub total_delivered: u64,
}

Synchronous, in-process publish-subscribe bus for network events.

Thread safety

NetworkEventBus is intentionally not Send or Sync. If you need to share it across threads, wrap it in Arc<Mutex<NetworkEventBus>>.

Example

use ipfrs_network::{
    NebNetworkEvent, NebSubscription,
    EventBusConfig, EventFilter, EventTopic, NetworkEventBus,
};

let mut bus = NetworkEventBus::new(EventBusConfig::default());

// Subscribe to peer-connection events only.
let sub_id = bus.subscribe(EventFilter::TopicIn(vec![EventTopic::PeerConnected]));

// Publish an event.
let _event_id = bus
    .publish(
        EventTopic::PeerConnected,
        b"hello".to_vec(),
        Some("peer-abc".to_string()),
        1_000,
    )
    .expect("publish failed");

// Retrieve matching events for the subscriber.
let events = bus.drain_events_for(sub_id).expect("drain failed");
assert_eq!(events.len(), 1);

Fields

config: EventBusConfig

Configuration that governs limits and buffer sizes.

subscriptions: HashMap<u64, NebSubscription>

Live subscriptions, keyed by their numeric id.

replay_buffer: VecDeque<NebNetworkEvent>

Ring buffer of recent events available for replay.

next_event_id: u64

Counter used to assign unique ids to new events.

next_sub_id: u64

Counter used to assign unique ids to new subscriptions.

total_published: u64

Total number of events that have been successfully published.

total_delivered: u64

Total number of (subscriber, event) delivery pairs.

Implementations

impl NetworkEventBus

pub fn new(config: EventBusConfig) -> Self

Create a new bus with the supplied configuration.

pub fn matches_filter(filter: &EventFilter, event: &NebNetworkEvent) -> bool

Returns true if event satisfies filter.

pub fn subscribe(&mut self, filter: EventFilter) -> SubscriberId

Register a new subscriber with the given filter.

Returns the assigned SubscriberId. If the bus is already at capacity, SubscriberId(0) is returned as a sentinel (no subscription is created).

pub fn unsubscribe(&mut self, id: SubscriberId) -> bool

Remove the subscription identified by id.

Returns true if the subscription existed and was removed, false if no subscription with that id was found.

pub fn subscriber_stats(&self, id: SubscriberId) -> Option<&NebSubscription>

Return an immutable reference to the NebSubscription for id, or None if no such subscription exists.

pub fn publish( &mut self, topic: EventTopic, payload: Vec<u8>, source_peer: Option<String>, now: u64, ) -> Result<u64, BusError>

Publish an event to the bus.

Errors

• BusError::PayloadTooLarge – payload.len() > config.max_payload_bytes.

Returns

The assigned event id (monotonically increasing).

pub fn replay_for_subscriber( &self, id: SubscriberId, since_event_id: u64, ) -> Result<Vec<&NebNetworkEvent>, BusError>

Return all buffered events with id > since_event_id that match the subscriber’s filter.

Errors

• BusError::SubscriberNotFound if id does not correspond to an active subscription.

pub fn drain_events_for( &mut self, id: SubscriberId, ) -> Result<Vec<NebNetworkEvent>, BusError>

Clone all buffered events that match the subscriber’s filter and return them. The replay buffer is not modified.

Errors

• BusError::SubscriberNotFound if id does not correspond to an active subscription.

pub fn event_bus_stats(&self) -> EventBusStats

Return a snapshot of bus-wide statistics.

Trait Implementations

impl Default for NetworkEventBus

fn default() -> Self

Returns the “default value” for a type.