rustlavel-queue 0.1.0

rustlavel-queue: background jobs and scheduling.

Work that should not happen while someone is waiting for a response — sending mail, resizing an image, calling a slow API — goes on a queue and is run by a worker. Work that should happen at a particular time goes on a schedule.

// Define a job.
struct SendWelcomeEmail { user_id: i64 }

impl Job for SendWelcomeEmail {
    const NAME: &'static str = "send-welcome-email";

    fn payload(&self) -> Json {
        Json::object([("user_id", Json::from(self.user_id))])
    }

    fn from_payload(payload: &Json) -> Result<Self> {
        Ok(SendWelcomeEmail {
            user_id: payload.get("user_id").and_then(Json::as_i64).unwrap_or_default(),
        })
    }

    fn handle(&self) -> impl Future<Output = Result<()>> + Send {
        async move { Ok(()) }
    }
}

// Dispatch it from a handler.
queue.dispatch(&SendWelcomeEmail { user_id }).await?;

// Run it, in `queue:work`.
let mut jobs = JobRegistry::new();
jobs.register::<SendWelcomeEmail>();

let shutdown = Shutdown::new();
shutdown.on_ctrl_c();
run_pool(Worker::new(queue, Arc::new(jobs)), 4, shutdown).await?;

The one thing that is not like Laravel

Laravel serialises the job object and asks PHP to bring the class back. A compiled language cannot resurrect a type from a string, so the way back from a stored name to running code is stated once, at boot, in a [JobRegistry]. That is the only line of ceremony the design adds, and it buys a queue:work that fails to compile against a renamed job rather than failing at three in the morning against a class that is no longer there.

What is in here

• [Job] and [JobRegistry] — defining work and finding it again.
• [Queue] and [QueueExt] — the driver contract and its conveniences.
• [MemoryQueue], [DatabaseQueue], [FakeQueue] — the three drivers.
• [Worker], [run_pool], [Shutdown] — running jobs, and stopping well.
• [Scheduler] and [Cron] — running work at a time rather than on demand.
• [QueueDashboard] — the plugin that exposes it all over HTTP.

Everything the queue does is reported on rustlavel_core::events as queue.pushed, queue.processed and queue.failed, so Telescope shows jobs without this crate knowing Telescope exists.