Struct PostgresFlowTaskQueue 

pub struct PostgresFlowTaskQueue { /* private fields */ }

A3S ORM-backed PostgreSQL task queue for shared workers.

Pending and inflight tasks live in one table and are scoped by queue_name. Leasing uses an atomic FOR UPDATE SKIP LOCKED CTE, so multiple workers can lease concurrently without taking the same task. Heartbeats rotate fencing tokens; stale acknowledgements cannot delete a task owned by another worker.

Implementations

impl PostgresFlowTaskQueue

pub async fn connect(database_url: impl AsRef<str>) -> Result<Self>

Connects to PostgreSQL, migrates the schema, and uses the default queue.

pub async fn connect_verified(database_url: impl AsRef<str>) -> Result<Self>

Connects to PostgreSQL, verifies a separately migrated schema, and uses the default queue without acquiring DDL authority.

pub async fn connect_with_queue( database_url: impl AsRef<str>, queue_name: impl AsRef<str>, ) -> Result<Self>

Connect with the ORM’s bounded non-TLS pool and run Flow migrations.

Production hosts that require TLS or custom pool controls should create a configured PostgresExecutor and call Self::from_executor_with_queue.

pub async fn connect_verified_with_queue( database_url: impl AsRef<str>, queue_name: impl AsRef<str>, ) -> Result<Self>

Connect with the ORM’s bounded non-TLS pool and verify a separately migrated Flow schema for the named queue.

pub async fn from_executor(executor: PostgresExecutor) -> Result<Self>

Uses a configured executor, migrates the schema, and uses the default queue.

pub async fn from_executor_verified(executor: PostgresExecutor) -> Result<Self>

Uses a configured executor, verifies the Flow schema without mutation, and uses the default queue.

pub async fn from_executor_with_queue( executor: PostgresExecutor, queue_name: impl AsRef<str>, ) -> Result<Self>

Uses a configured executor and migrates the named queue schema.

pub async fn from_executor_verified_with_queue( executor: PostgresExecutor, queue_name: impl AsRef<str>, ) -> Result<Self>

Uses a configured executor and verifies the complete Flow schema for a named queue without applying migrations.

pub fn executor(&self) -> &PostgresExecutor

Returns the configured A3S ORM executor.

pub fn queue_name(&self) -> &str

Returns the logical queue name used to scope rows.

pub async fn inflight_len(&self) -> Result<usize>

Returns the number of currently leased tasks.

pub async fn dead_letter_len(&self) -> Result<usize>

Returns the number of dead-lettered tasks.

pub async fn dead_lettered_tasks(&self) -> Result<Vec<PostgresDeadLetteredTask>>

Loads dead-lettered tasks in durable insertion order.

pub async fn requeue_inflight_older_than( &self, cutoff: DateTime<Utc>, ) -> Result<usize>

Returns leases at or before cutoff to pending dispatch.

pub async fn dead_letter_inflight_older_than( &self, cutoff: DateTime<Utc>, reason: impl Into<String>, ) -> Result<usize>

Atomically moves leases at or before cutoff to the dead-letter table.

Trait Implementations

impl Clone for PostgresFlowTaskQueue

fn clone(&self) -> PostgresFlowTaskQueue

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PostgresFlowTaskQueue

fn fmt(&self, formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl FlowTaskQueue for PostgresFlowTaskQueue

fn enqueue<'life0, 'async_trait>( &'life0 self, task: FlowTask, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Appends one task to pending dispatch.

fn lease<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<Option<FlowTaskLease>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Leases the next pending task without acknowledging it.

fn heartbeat<'life0, 'life1, 'async_trait>( &'life0 self, lease_id: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<String>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Refreshes an active lease and returns its replacement fencing token.

fn ack<'life0, 'life1, 'async_trait>( &'life0 self, lease_id: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Acknowledges the active lease identified by its latest fencing token.

fn requeue_inflight<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<usize>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Returns inflight tasks to pending dispatch and reports the count.

fn len<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<usize>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Returns the number of tasks pending dispatch.

fn dequeue<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<Option<FlowTask>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Leases and immediately acknowledges the next pending task.

fn is_empty<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<bool>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Returns whether no tasks are pending dispatch.