Struct SqliteOutboxWorkerBuilder 

pub struct SqliteOutboxWorkerBuilder { /* private fields */ }

Fluent builder for an OutboxWorker backed by SqliteOutboxStore.

See the module documentation for the single-worker concurrency model.

Pool sizing and acquire timeout

SQLite uses a single-writer model. A pool size of 1–2 connections is typical: the worker holds one connection per poll cycle while publishers take the other. To prevent a stuck writer from blocking acquire() indefinitely, set an acquire timeout on the pool:

use sqlx::sqlite::SqlitePoolOptions;
use std::time::Duration;

let pool = SqlitePoolOptions::new()
    .max_connections(2)
    // surface PoolTimeout instead of blocking indefinitely
    .acquire_timeout(Duration::from_secs(5))
    .connect("sqlite:outbox.db")
    .await?;

let worker = SqliteOutboxWorkerBuilder::new(pool).build()?;

When acquire_timeout expires, OutboxStore::acquire returns OutboxError::PoolTimeout instead of hanging. The worker logs the error and retries after OutboxWorkerConfig::poll_interval.

Implementations

impl SqliteOutboxWorkerBuilder

pub fn new(pool: SqlitePool) -> Self

Start a new builder for the given pool.

pub fn table_name(self, name: impl Into<String>) -> Self

Override the outbox table name (default "audit_outbox").

pub fn dead_letter_table(self, name: impl Into<String>) -> Self

Enable dead-letter persistence for poison messages.

pub fn register_handler<E, H>(self, handler: H) -> Self

where E: Event, H: Handler<E>,

Register a typed handler for the event type E.

Registering twice for the same event type silently replaces the previous handler.

pub fn shared_handler<E, H>(self, handler: Arc<H>) -> Self

where E: Event, H: Handler<E>,

Register a handler already shared behind an Arc.

pub fn poll_interval(self, d: Duration) -> Self

Override the poll interval (default 100 ms).

pub fn batch_size(self, n: usize) -> Self

Override the batch size per poll (default 10).

pub fn max_attempts(self, n: u32) -> Self

Override the maximum number of attempts per envelope (default 5).

pub fn retry_base_delay(self, d: Duration) -> Self

Override the base delay for exponential backoff (default 1 s).

pub fn retry_max_delay(self, d: Duration) -> Self

Override the maximum backoff delay (default 5 min).

pub fn jitter(self, enabled: bool) -> Self

Enable or disable full jitter on the backoff delay (default true).

pub fn dispatch_timeout(self, d: Duration) -> Self

Override the soft-lease duration for claimed envelopes (default 30 s).

SQLite has no FOR UPDATE SKIP LOCKED and therefore no competing-consumer claim, so this store is meant for a single worker (see the module documentation); running several workers against one database can still double-dispatch. The lease is recorded on claim alongside the attempt increment, but with a single writer it only affects when a crashed-and-restarted worker re-picks an in-flight row.

pub fn build(self) -> Result<OutboxWorker<SqliteOutboxStore>, OutboxError>

Consume the builder and produce an OutboxWorker ready to spawn.

Errors

Returns OutboxError::Internal if the configured table_name is not a valid identifier.