GooglePubSub

GooglePubSub names one subscription by short id or full resource name and carries its settings: topology, flow control, leases and batches.

GooglePubSub::new takes the subscription's name, and builder steps add the rest. create_with_topic creates the subscription and its topic at startup. max_outstanding caps the deliveries that may be unsettled at once. ack_extension and max_lease shape how the client keeps a delivery leased. batch_wait bounds how long a partial batch waits for the rest. A setting the descriptor leaves out keeps the client library's default.

The descriptor is plain data and holds no connection. It opens against the connected broker at startup, so the declaration a service ships is the one its tests run.

Example

The subscription orders-workers on the topic orders, with at most 100 orders unsettled at once.

Macros
Manual

examples/pubsub_subscriptions_descriptor.rs
/// The subscription `orders-workers` on the topic `orders`, with at most 100 orders unsettled.
#[subscriber(
    GooglePubSub::new("orders-workers")
        .create_with_topic("orders")
        .max_outstanding(100)
)]
async fn place(order: &Order) -> HandlerOutcome {
    tracing::info!(order.id, "order placed");
    HandlerOutcome::ack()
}

examples/manual/pubsub_subscriptions_descriptor.rs
/// The subscription `orders-workers` on the topic `orders`, with at most 100 orders unsettled.
fn orders() -> GooglePubSub {
    GooglePubSub::new("orders-workers")
        .create_with_topic("orders")
        .max_outstanding(100)
}

Example​

Example