Struct DatabaseQueue 

pub struct DatabaseQueue { /* private fields */ }

A queue backed by two database tables.

Survives a restart, and is shared by every process pointed at the same database — which is the whole reason to prefer it over the memory driver.

Implementations

impl DatabaseQueue

pub fn new(db: Database) -> Self

Use the conventional jobs and failed_jobs tables.

pub fn with_tables(db: Database, jobs: &str, failed: &str) -> Result<Self>

Use table names of your own. Validated and quoted here, once, for the database this queue is talking to — "jobs" on PostgreSQL and SQLite, `jobs` on MySQL, [jobs] on SQL Server. The shared quote_identifier helper always writes double quotes, which MySQL reads as a string literal rather than a table.

pub fn database(&self) -> &Database

pub async fn migrate(&self) -> Result<()>

Create the tables directly, for an application that would rather not register CreateQueueTables in its migration registry.

pub async fn drop_tables(&self) -> Result<()>

Drop the tables. Intended for tests and queue:fresh.

pub async fn reclaim_expired(&self, queue: &str) -> Result<u64>

Release jobs whose worker never came back.

A worker that is killed between reserving and finishing leaves reserved_at set forever. Once the job’s own retry_after has passed with no result, the job is assumed orphaned and goes back on the queue.

Called only when the queue looks empty, so the common path — a worker picking up one of many waiting jobs — pays nothing for it.

Trait Implementations

impl Clone for DatabaseQueue

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Queue for DatabaseQueue

fn driver(&self) -> &'static str

The driver’s name. It appears in queue.* events and error messages, which is how Telescope shows which backend handled a job.

fn push(&self, job: QueuedJob) -> BoxFuture<'_, Result<String>>

Store a job. Returns the driver’s identifier for it.

fn pop<'a>( &'a self, queue: &'a str, ) -> BoxFuture<'a, Result<Option<ReservedJob>>>

Reserve the next available job, or None when there is nothing ready.

fn size<'a>(&'a self, queue: &'a str) -> BoxFuture<'a, Result<u64>>

How many jobs are waiting on a queue, including delayed ones.

fn delete<'a>(&'a self, job: &'a ReservedJob) -> BoxFuture<'a, Result<()>>

Finish with a reserved job: it succeeded and is gone.

fn release<'a>( &'a self, job: &'a ReservedJob, delay: Duration, ) -> BoxFuture<'a, Result<()>>

Put a reserved job back, available again after delay.

fn fail<'a>( &'a self, job: &'a ReservedJob, error: &'a str, ) -> BoxFuture<'a, Result<()>>

Move a reserved job to the dead-letter store with the error that killed it. It must no longer be on the queue afterwards.

fn failed_jobs(&self) -> BoxFuture<'_, Result<Vec<FailedJob>>>

Everything in the dead-letter store, oldest first.

fn clear<'a>(&'a self, queue: &'a str) -> BoxFuture<'a, Result<u64>>

Throw away every job waiting on a queue. Returns how many went.

fn push_on<'a>( &'a self, queue: &'a str, job: QueuedJob, ) -> BoxFuture<'a, Result<String>>

Store a job on a named queue, whatever the job itself asked for.

fn later<'a>( &'a self, delay: Duration, job: QueuedJob, ) -> BoxFuture<'a, Result<String>>

Store a job that only becomes visible to a worker after delay.