Struct async_nats::jetstream::message::Acker
source · pub struct Acker { /* private fields */ }
Expand description
A lightweight struct useful for decoupling message contents and the ability to ack it.
Implementations§
source§impl Acker
impl Acker
pub fn new(context: Context, reply: Option<Subject>) -> Self
sourcepub async fn ack(&self) -> Result<(), Error>
pub async fn ack(&self) -> Result<(), Error>
Acknowledges a message delivery by sending +ACK
to the server.
If AckPolicy is set to All
or Explicit
, messages has to be acked.
Otherwise redeliveries will occur and Consumer will not be able to advance.
§Examples
use async_nats::jetstream::consumer::PullConsumer;
use async_nats::jetstream::Message;
use futures::StreamExt;
let client = async_nats::connect("localhost:4222").await?;
let jetstream = async_nats::jetstream::new(client);
let consumer: PullConsumer = jetstream
.get_stream("events")
.await?
.get_consumer("pull")
.await?;
let mut messages = consumer.fetch().max_messages(100).messages().await?;
while let Some(message) = messages.next().await {
let (message, acker) = message.map(Message::split)?;
// Do something with the message. Ownership can be taken over `Message`
// while retaining ability to ack later.
println!("message: {:?}", message);
// Ack it. `Message` may be dropped already.
acker.ack().await?;
}
sourcepub async fn ack_with(&self, kind: AckKind) -> Result<(), Error>
pub async fn ack_with(&self, kind: AckKind) -> Result<(), Error>
Acknowledges a message delivery by sending a chosen AckKind variant to the server.
§Examples
use async_nats::jetstream::consumer::PullConsumer;
use async_nats::jetstream::AckKind;
use async_nats::jetstream::Message;
use futures::StreamExt;
let client = async_nats::connect("localhost:4222").await?;
let jetstream = async_nats::jetstream::new(client);
let consumer: PullConsumer = jetstream
.get_stream("events")
.await?
.get_consumer("pull")
.await?;
let mut messages = consumer.fetch().max_messages(100).messages().await?;
while let Some(message) = messages.next().await {
let (message, acker) = message.map(Message::split)?;
// Do something with the message. Ownership can be taken over `Message`.
// while retaining ability to ack later.
println!("message: {:?}", message);
// Ack it. `Message` may be dropped already.
acker.ack_with(AckKind::Nak(None)).await?;
}
sourcepub async fn double_ack(&self) -> Result<(), Error>
pub async fn double_ack(&self) -> Result<(), Error>
Acknowledges a message delivery by sending +ACK
to the server
and awaits for confirmation for the server that it received the message.
Useful if user wants to ensure exactly once
semantics.
If AckPolicy is set to All
or Explicit
, messages has to be acked.
Otherwise redeliveries will occur and Consumer will not be able to advance.
§Examples
use async_nats::jetstream::Message;
use futures::StreamExt;
let client = async_nats::connect("localhost:4222").await?;
let jetstream = async_nats::jetstream::new(client);
let consumer = jetstream
.get_stream("events")
.await?
.get_consumer("pull")
.await?;
let mut messages = consumer.fetch().max_messages(100).messages().await?;
while let Some(message) = messages.next().await {
let (message, acker) = message.map(Message::split)?;
// Do something with the message. Ownership can be taken over `Message`.
// while retaining ability to ack later.
println!("message: {:?}", message);
// Ack it. `Message` may be dropped already.
acker.double_ack().await?;
}
Auto Trait Implementations§
impl !Freeze for Acker
impl !RefUnwindSafe for Acker
impl Send for Acker
impl Sync for Acker
impl Unpin for Acker
impl !UnwindSafe for Acker
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more