Trait BuiltInDialect

Source

pub trait BuiltInDialect: QueueDatabase {
    // Required method
    fn dialect(conn: &Self::Connection) -> Option<BuiltIn<Self>>;
}

Expand description

A database whose dialect is built into this crate, so SqlxBroker::new needs no dialect of the service’s own.

Postgres (feature postgres), MySQL with MariaDB (feature mysql) and SQLite (feature sqlite) have one, BuiltIn<DB>. Any (feature any) takes the dialect of the database its pool reaches, among those whose features are on, and the broker picks it when it connects. A row on an AnyPool holds only the types sqlx::Any carries, and no time is among them, so a table with locked_until, retry_after or processed_at is out of its reach.

§Examples

use ruststream_sqlx::prelude::*;
use serde::Deserialize;
use sqlx::AnyPool;

// The columns `sqlx::Any` carries: integers, text and bytes, no time.
#[derive(Inbox, sqlx::FromRow)]
#[inbox(table = "email_jobs")]
pub struct SendEmail {
    #[field(id, generated)]
    job_id: i64,
    #[field(group)]
    name: String,
    #[field(attempt, generated)]
    attempt: i32,
    #[field(payload)]
    payload: Vec<u8>,
}

#[derive(Deserialize)]
struct Email {
    to: String,
}

#[subscriber(InboxQueue::<SendEmail>::new("emails"))]
async fn send(email: &Email) -> HandlerOutcome {
    tracing::info!(to = %email.to, "sending");
    HandlerOutcome::ack()
}

// One build for every deployment: `Any` is a `BuiltInDialect`, and the broker takes the
// dialect of the database the URL names, Postgres or MySQL, when it connects. `main` installs
// sqlx's drivers (`sqlx::any::install_default_drivers`) before it builds the pool.
pub fn app(pool: AnyPool) -> RustStream {
    RustStream::new(AppInfo::new("mailer", "0.1.0")).with_broker(SqlxBroker::new(pool), |b| {
        b.include(send);
    })
}

Required Methods§

Source

fn dialect(conn: &Self::Connection) -> Option<BuiltIn<Self>>

The dialect that builds the statements of the database conn reaches, or None when no built-in dialect serves it: an AnyPool’s backend whose feature is off.

Postgres, MySQL and SQLite answer without reading conn; the broker asks with the connection it checks when it connects.