Struct PoolContext 

pub struct PoolContext<DB: QueueDatabase> { /* private fields */ }

What every delivery of an InboxQueue subscription on DB lends: the context Ctx<keys::Pool<DB>> reads, and Ctx<keys::Attempt> after it.

It is built only for a handler whose first Ctx reads it, and copies the pool’s reference and the attempt.

Examples

use ruststream_sqlx::prelude::*;
use sqlx::Postgres;

// `keys::Pool` comes first, so the handler's context is `PoolContext<Postgres>`.
#[subscriber(InboxQueue::<Job>::new("uploads"))]
async fn scan(
    upload: &Upload,
    Ctx(pool): Ctx<keys::Pool<Postgres>>,
    Ctx(attempt): Ctx<keys::Attempt>,
) -> HandlerOutcome {
    let logged = sqlx::query("INSERT INTO scans (name, attempt) VALUES ($1, $2)")
        .bind(&upload.name)
        .bind(attempt.and_then(|attempt| i64::try_from(attempt).ok()))
        .execute(&pool)
        .await;
    if logged.is_ok() { HandlerOutcome::ack() } else { HandlerOutcome::retry() }
}

Trait Implementations

impl<DB, Row, Mode> BuildContext<InboxDelivery<DB, Row, Mode>> for PoolContext<DB>

where DB: QueueDatabase, Row: Events<DB>, Mode: InboxMode,

fn build(msg: &InboxDelivery<DB, Row, Mode>) -> Self

Builds the context value by reading fields out of msg.

impl<DB: QueueDatabase> Clone for PoolContext<DB>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<DB: QueueDatabase> Copy for PoolContext<DB>

impl<DB: QueueDatabase> Debug for PoolContext<DB>

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

Formats the value using the given formatter.

impl<S: Sync, DB: QueueDatabase> FromContext<PoolContext<DB>, S> for Ctx<Attempt>

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<'_, PoolContext<DB>, S>, ) -> 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.