Struct Subscriber 

pub struct Subscriber { /* private fields */ }

A Subscriber client for the Cloud Pub/Sub API.

Use this client to receive messages from a pull subscription on a topic.

Example

let client = Subscriber::builder().build().await?;
let mut stream = client
    .subscribe("projects/my-project/subscriptions/my-subscription")
    .build();
while let Some((m, h)) = stream.next().await.transpose()? {
    println!("Received message m={m:?}");
    h.ack();
}

Ordered Delivery

The subscriber returns messages in order if ordered delivery is enabled on the subscription. The client provides the same guarantees as the service.

For more details on how the service works, see:

• Considerations when using ordered delivery
• Google Cloud Pub/Sub Ordered Delivery

Exactly-once Delivery

The subscriber does not support exactly-once delivery yet.

If you subscribe to a subscription with exactly-once delivery enabled, the subscriber will deliver you messages with at-least-once semantics. There is no way for you to confirm the acknowledgements from the server. Messages may get redelivered.

Adding support for exactly-once delivery is planned. You can track the progress in google-cloud-rust#3964.

Configuration

To configure a Subscriber use the with_* methods in the type returned by builder(). The default configuration should work for most applications. Common configuration changes include:

• with_endpoint(): by default this client uses the global default endpoint (https://pubsub.googleapis.com). Applications using regional endpoints or running in restricted networks (e.g. a network configured with Private Google Access with VPC Service Controls) may want to override this default.
• with_credentials(): by default this client uses Application Default Credentials. Applications using custom authentication may need to override this default.

Pooling and Cloning

Subscriber holds a connection pool internally, it is advised to create one and then reuse it. You do not need to wrap Subscriber in an Rc or Arc to reuse it, because it already uses an Arc internally.

Implementations

impl Subscriber

pub fn builder() -> ClientBuilder

Returns a builder for Subscriber.

Example

let client = Subscriber::builder().build().await?;

pub fn subscribe<T>(&self, subscription: T) -> Subscribe

where T: Into<String>,

Receive messages from a subscription.

The subscription is the full name, in the format of projects/*/subscriptions/*.

Example

let mut stream = client
    .subscribe("projects/my-project/subscriptions/my-subscription")
    .build();
while let Some((m, h)) = stream.next().await.transpose()? {
    println!("Received message m={m:?}");
    h.ack();
}

Trait Implementations

impl Clone for Subscriber

fn clone(&self) -> Subscriber

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Subscriber

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

Formats the value using the given formatter.