Struct JetStreamContext 

pub struct JetStreamContext { /* private fields */ }

Native JetStream per-delivery metadata, built once per delivery from the broker message.

Read its fields by the compile-time keys (for example keys::STREAM_SEQUENCE). On a core (non-JetStream) delivery there is no such metadata, so the context is empty and every key reads None; the same handler therefore works on both kinds of subscription.

The context owns its fields (it copies them out of the delivery), so it does not borrow the message: numbers are a stack copy and the stream/consumer names are cloned once per delivery.

Examples

use ruststream::schemars::JsonSchema;
use ruststream_nats::context::{JetStreamContext, keys};
use ruststream_nats::prelude::*;
use serde::Deserialize;

#[derive(Deserialize, JsonSchema)]
struct Order {
    id: u64,
}

struct Ledger;

impl Handle<Order, (), (), JetStreamContext> for Ledger {
    async fn handle(
        &self,
        order: &Order,
        _outs: &(),
        ctx: &mut Context<'_, JetStreamContext>,
    ) -> Result<(), HandlerOutcome> {
        if let Some(sequence) = ctx.context(keys::STREAM_SEQUENCE) {
            tracing::info!(order.id, sequence, "entered in the ledger");
        }
        Ok(())
    }
}

#[ruststream::app]
fn app() -> impl App {
    RustStream::new(AppInfo::new("ledger", "0.1.0")).with_broker(
        NatsBroker::new("nats://localhost:4222"),
        |b| {
            b.include(subscriber(
                JetStreamSubject::new("orders.*", "ORDERS").durable("ledger"),
                Ledger,
            )
            .build());
        },
    )
}

Trait Implementations

impl BuildContext<NatsMessage> for JetStreamContext

fn build(msg: &NatsMessage) -> Self

Builds the context value by reading fields out of msg.

impl Clone for JetStreamContext

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for JetStreamContext

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

Formats the value using the given formatter.

impl Default for JetStreamContext

fn default() -> Self

Returns the “default value” for a type.

impl Eq for JetStreamContext

impl Field<JetStreamContext> for StreamSequence

type Value<'a> = Option<u64>

The value read through this key, borrowed from the source for 'a.

fn get(self, cx: &JetStreamContext) -> Option<u64>

Reads this key’s field out of src.

impl Field<JetStreamContext> for ConsumerSequence

type Value<'a> = Option<u64>

The value read through this key, borrowed from the source for 'a.

fn get(self, cx: &JetStreamContext) -> Option<u64>

Reads this key’s field out of src.

impl Field<JetStreamContext> for Delivered

type Value<'a> = Option<i64>

The value read through this key, borrowed from the source for 'a.

fn get(self, cx: &JetStreamContext) -> Option<i64>

Reads this key’s field out of src.

impl Field<JetStreamContext> for Pending

type Value<'a> = Option<u64>

The value read through this key, borrowed from the source for 'a.

fn get(self, cx: &JetStreamContext) -> Option<u64>

Reads this key’s field out of src.

impl Field<JetStreamContext> for Stream

type Value<'a> = Option<&'a str>

The value read through this key, borrowed from the source for 'a.

fn get(self, cx: &JetStreamContext) -> Option<&str>

Reads this key’s field out of src.

impl Field<JetStreamContext> for Consumer

type Value<'a> = Option<&'a str>

The value read through this key, borrowed from the source for 'a.

fn get(self, cx: &JetStreamContext) -> Option<&str>

Reads this key’s field out of src.

impl PartialEq for JetStreamContext

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for JetStreamContext