Struct CustomBackend 

pub struct CustomBackend<Args, DB, Fetch, Sink, Config = ()> { /* private fields */ }

A highly customizable backend for integration with any persistence engine

This backend allows you to define how tasks are fetched from and persisted to your storage, meaning you can use it to integrate with existing systems.

Example

let backend = BackendBuilder::new()
    .database(my_db)
    .fetcher(my_fetcher_fn)
    .sink(my_sink_fn)
    .build()
    .unwrap();

Features

Feature	Status	Description
TaskSink	✅	Ability to push new tasks
Serialization	✅	Serialization support for arguments
FetchById	❌	Allow fetching a task by its ID
RegisterWorker	⚠️	Allow registering a worker with the backend
PipeExt	✅ ❗	Allow other backends to pipe to this backend
BackendFactory	⚠️	Share the same CustomBackend across multiple workers
Workflow	⚠️	Flexible enough to support workflows
WaitForCompletion	⚠️	Wait for tasks to complete without blocking
ResumeById	❌	Resume a task by its ID
ResumeAbandoned	❌	Resume abandoned tasks
ListWorkers	⚠️	List all workers registered with the backend
ListTasks	⚠️	List all tasks in the backend

Key: ✅ : Supported | ⚠️ : Not implemented | ❌ : Not Supported | ❗ Limited support

Tests:

Trait Implementations

impl<Args: 'static, DB, Fetch, S, E, Config> Backend for CustomBackend<Args, DB, Fetch, S, Config>

where Fetch: Stream<Item = Result<Option<Task<Args>>, E>> + Unpin + Send + 'static, S: Sink<Task<Args>, Error = E> + Unpin + Send + 'static, E: Into<BoxDynError>,

type Task = Task<Args>

The type of task the backend emits.

type Error = CustomBackendError

The error type returned by backend operations

fn poll_ready( &mut self, _: &mut Context<'_>, _: &WorkerContext, ) -> Poll<Result<(), Self::Error>>

Polls whether the backend is ready for the worker to request more work.

fn poll_next( &mut self, cx: &mut Context<'_>, worker: &WorkerContext, ) -> Poll<Option<Result<Self::Task, Self::Error>>>

Polls the backend for the next available task for this worker.

fn poll_close( &mut self, cx: &mut Context<'_>, _: &WorkerContext, ) -> Poll<Result<(), Self::Error>>

Flushes/releases any resources the backend holds (pending acks, open subscriptions, connections) before the worker fully shuts down.

impl<Args, DB, Fetch, S, Config, E> BackendConfig for CustomBackend<Args, DB, Fetch, S, Config>

where Fetch: Stream<Item = Result<Option<Task<Args>>, E>> + Unpin + Send + 'static, S: Sink<Task<Args>, Error = E> + Unpin + Send + 'static, E: Into<BoxDynError>, Args: 'static,

type Id = RandomId

The internal type of this Backend’s TaskId

type Args = Args

The type of argument this backend emits

type Kind = Ephemeral

This defines the kind of Backend

type Layer = Identity

The type representing backend middleware layer.

type Config = Config

The config for the backend

fn config(&self) -> &Self::Config

Returns the config associated with the backend.

fn middleware(&mut self, _: &mut WorkerContext) -> Self::Layer

Returns the backend’s middleware layer.

impl<Args, DB, Fetch, Sink, Config> Clone for CustomBackend<Args, DB, Fetch, Sink, Config>

where DB: Clone, Config: Clone,

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<Args, DB, Fetch, Sink, Config> Debug for CustomBackend<Args, DB, Fetch, Sink, Config>

where DB: Debug, Config: Debug,

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

Formats the value using the given formatter.

impl<Args, DB, Fetch, S, Config> Sink<Task<Args>> for CustomBackend<Args, DB, Fetch, S, Config>

where S: Sink<Task<Args>>, S::Error: Into<BoxDynError>,

type Error = CustomBackendError

The type of value produced by the sink when an error occurs.

fn poll_ready( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Result<(), Self::Error>>

Attempts to prepare the Sink to receive a value.

fn start_send(self: Pin<&mut Self>, item: Task<Args>) -> Result<(), Self::Error>

Begin the process of sending a value to the sink. Each call to this function must be preceded by a successful call to poll_ready which returned Poll::Ready(Ok(())).

fn poll_flush( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Result<(), Self::Error>>

Flush any remaining output from this sink.

fn poll_close( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Result<(), Self::Error>>

Flush any remaining output and close this sink, if necessary.

impl<'pin, Args, DB, Fetch, Sink, Config> Unpin for CustomBackend<Args, DB, Fetch, Sink, Config>

where PinnedFieldsOf<__CustomBackend<'pin, Args, DB, Fetch, Sink, Config>>: Unpin,