Job attributes

#[proc_macro_derive(Job, attributes(job))]

Applies to any type that is also Serialize + DeserializeOwned + Send + Sync + 'static. Generic types are not supported.

`#[job(...)]`

Key	Type	Valid range	Default
`queue`	path expression	required; at least two segments, e.g. `AppQueues::Emails`	—
`name`	string literal	any	`concat!(module_path!(), "::", stringify!(Type))`
`retry(...)`	nested list	see below	omitted, so `Job::retry_policy()` stays `None` and the queue’s policy applies
`crate`	string literal (module path)	same rules as `#[queues(crate = ...)]`	auto-resolved

The queue path is split: the last segment becomes the constant Job::QUEUE, and everything before it becomes the associated type Job::Queue. That is why a single-segment path cannot work.

The `retry(...)` grammar

The same grammar in #[job(...)] and #[queue(...)].

retry(
    max_attempts = 3,          // u32 >= 1, default 3 (1 = no retries)
    backoff = "exponential",   // "none" | "fixed" | "exponential", default "exponential"
    delay = "1s",              // fixed ONLY, required when backoff = "fixed"
    base = "1s",               // exponential ONLY, default "1s", must be <= max
    factor = 2.0,              // exponential ONLY, default 2.0, finite and > 0
    max = "5m",                // exponential ONLY, default "5m"
    jitter = true,             // exponential ONLY, default true
)

retry() with an empty body is accepted and uses every default.

Key	Valid with	Default
`max_attempts`	every backoff	`3`
`backoff`	—	`"exponential"`
`delay`	`backoff = "fixed"` only, and required there	—
`base`	`backoff = "exponential"` only	`"1s"`
`factor`	`backoff = "exponential"` only	`2.0`
`max`	`backoff = "exponential"` only	`"5m"`
`jitter`	`backoff = "exponential"` only	`true`

factor accepts a float, a plain integer (2) and a negative literal, though a negative one is then rejected by the range check.

Duration literals

An integer followed by ms, s, m, h or d; a bare integer means seconds. Full rules and the rejected forms are in Queue attributes.

Compile errors

Mistake	Message
No `queue` key	#[derive(Job)] requires `#[job(queue = MyQueues::Variant)]`
A single-segment `queue` path	`queue` must be a path to an enum variant such as `AppQueues::Emails`
A generic job type	`generic job types are not supported`
An unknown key	lists `queue, name, retry, crate`
`max_attempts = 0`	`max_attempts` must be >= 1; 1 means no retries
An unknown backoff	unknown backoff `linear`, expected "none", "fixed" or "exponential"
`delay` with a non-fixed backoff	`delay` is only valid with `backoff = "fixed"`
`backoff = "fixed"` with no `delay`	`backoff = "fixed"` requires `delay = "..."`
`base`, `factor`, `max` or `jitter` with a non-exponential backoff	`<key>` is only valid with `backoff = "exponential"`
`base` greater than `max`	`base` must be <= `max`, spanned at whichever of the two you wrote
A non-finite or non-positive `factor`	`factor` must be a finite number greater than 0
`delay = "0s"`	`delay` must be greater than zero: express "no backoff" as `backoff = "none"` instead
An unknown `retry` key	lists `max_attempts, backoff, delay, base, factor, max, jitter`

Type errors from the binding

The derive is what makes these three cases fail to compile. All are covered by compile-fail tests:

Attempt	Error
Enqueueing a job from another queue set	`E0271` type mismatch on `<J as Job>::Queue == Q`
Registering a handler for a foreign job	the same, on `WorkerBuilder::handler`
Wrapping a foreign job in `FnHandler`	the same

See Jobs for the full error text.

What is generated

pub trait Job: Serialize + DeserializeOwned + Send + Sync + 'static {
    type Queue: QueueSet;
    const NAME: &'static str;
    const QUEUE: Self::Queue;
    fn retry_policy() -> Option<RetryPolicy> { None }
}

retry_policy() is only generated when the attribute has a retry(...). Without it, the default None means “use the queue’s policy”.