Struct StreamContext 

pub struct StreamContext { /* private fields */ }

Per-delivery context for a Redis Streams delivery (RedisMessage).

Built once per delivery from the message. Read its fields by keys key off a ruststream::runtime::Context, or bind one as a handler parameter with the core Ctx<K> extractor. A body that repositions its group names this type as its context and needs nothing else: the keys::SeekHandle key carries the live handle.

Examples

use ruststream_fred::stream::prelude::*;

/// Skips the group past a region the producer marked poisoned, and logs where it was.
#[subscriber(RedisStream::new("orders").group("workers"))]
async fn work(order: &Order, ctx: &mut Context<'_, StreamContext>) -> HandlerOutcome {
    if order.id != 0 {
        return HandlerOutcome::ack();
    }
    tracing::warn!(entry = %ctx.context(keys::EntryId), "poison marker");
    match ctx.context(keys::SeekHandle).seek(RedisGroupPosition::end()).await {
        Ok(()) => HandlerOutcome::ack(),
        Err(_) => HandlerOutcome::retry(),
    }
}

Implementations

impl StreamContext

pub const fn entry_id(&self) -> EntryId

The stream entry id (for example 1700000000000-0) this delivery was read at.

pub const fn position(&self) -> RedisGroupPosition

The group cursor that redelivers this entry, as Positioned reports it: the cursor is exclusive, so it sits one id below the entry’s own.

pub fn consumer_group(&self) -> &str

The consumer group this delivery was read through.

pub const fn seeker(&self) -> &RedisGroupSeeker

The handle repositioning this delivery’s consumer group.

The cursor belongs to the group, so a seek through it moves every consumer of that group; see RedisGroupSeeker.

pub const fn pool(&self) -> &Pool

The broker’s connection pool, for a command whose answer the handler needs now.

Trait Implementations

impl BuildContext<RedisMessage> for StreamContext

fn build(msg: &RedisMessage) -> Self

Builds the context value by reading fields out of msg.

impl Clone for StreamContext

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 StreamContext

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

Formats the value using the given formatter.

impl Field<StreamContext> for FredPool

type Value<'a> = &'a Pool

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

fn get(self, src: &StreamContext) -> &Pool

Reads this key’s field out of src.

impl Field<StreamContext> for EntryId

type Value<'a> = EntryId

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

fn get(self, src: &StreamContext) -> EntryId

Reads this key’s field out of src.

impl Field<StreamContext> for Position

type Value<'a> = RedisGroupPosition

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

fn get(self, src: &StreamContext) -> RedisGroupPosition

Reads this key’s field out of src.

impl Field<StreamContext> for SeekHandle

type Value<'a> = &'a RedisGroupSeeker

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

fn get(self, src: &StreamContext) -> &RedisGroupSeeker

Reads this key’s field out of src.

impl Field<StreamContext> for ConsumerGroup

type Value<'a> = &'a str

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

fn get(self, src: &StreamContext) -> &str

Reads this key’s field out of src.

impl<State: Sync> FromContext<StreamContext, State> for Ctx<FredPool>

Ctx<keys::FredPool> beside a stream key: the handler’s context is StreamContext there.

type Rejection = !

The error returned when extraction fails. It is converted into a HandlerOutcome (the reflexive conversion makes HandlerOutcome itself a valid rejection, and Infallible works for an extractor that never fails) and the delivery is settled by that outcome, skipping the handler body.

fn from_context( ctx: &mut Context<'_, StreamContext, State>, ) -> impl Future<Output = Result<Self, Infallible>> + Send

Resolves the value from the delivery context. The context is borrowed mutably so an extractor may also read broker fields or take scratch a middleware left for it.