Struct PushSubscription 

pub struct PushSubscription { /* private fields */ }

A push-based subscription handle.

Receives ChangeEvents as they are pushed by the Ring 1 dispatcher. Dropping this handle automatically cancels the subscription in the SubscriptionRegistry.

Works naturally with tokio::select! and while let:

tokio::select! {
    event = sub.recv() => handle(event),
    _ = shutdown.recv() => break,
}

Implementations

impl PushSubscription

pub fn new( id: SubscriptionId, receiver: Receiver<ChangeEvent>, registry: Arc<SubscriptionRegistry>, query: String, ) -> Self

Creates a new push subscription.

This is pub(crate) — external callers create subscriptions via the pipeline or engine API, which resolves the query to a source_id and registers in the SubscriptionRegistry.

pub async fn recv(&mut self) -> Result<ChangeEvent, PushSubscriptionError>

Receives the next change event.

Awaits until an event is available or the subscription is closed.

Errors

• PushSubscriptionError::Cancelled if the subscription was cancelled.
• PushSubscriptionError::Lagged if n events were missed due to slow consumption. The receiver skips ahead and subsequent recv() calls return newer events.
• PushSubscriptionError::Closed if all senders have been dropped.

pub fn try_recv(&mut self) -> Option<Result<ChangeEvent, PushSubscriptionError>>

Tries to receive without blocking.

Returns None if no event is immediately available. Returns Some(Err(...)) on lagged, closed, or cancelled.

pub fn pause(&self) -> bool

Pauses the subscription.

While paused, events are either buffered or dropped depending on the backpressure configuration. Returns true if the subscription was active and is now paused.

pub fn resume(&self) -> bool

Resumes a paused subscription.

Returns true if the subscription was paused and is now active.

pub fn cancel(&mut self)

Cancels the subscription.

After cancellation, recv() returns PushSubscriptionError::Cancelled. The subscription is removed from the registry.

pub fn id(&self) -> SubscriptionId

Returns the subscription ID.

pub fn query(&self) -> &str

Returns the query string for this subscription.

pub fn is_cancelled(&self) -> bool

Returns true if the subscription has been cancelled.

pub fn metrics(&self) -> Option<SubscriptionMetrics>

Returns subscription metrics from the registry.

Trait Implementations

impl Drop for PushSubscription

fn drop(&mut self)

Executes the destructor for this type.