Struct CustomBackend 

pub struct CustomBackend<Args, DB, Fetch, Sink, IdType, Codec = IdentityCodec, 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
MakeShared	⚠️	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

Examples:

Trait Implementations

impl<Args, DB, Fetch, Sink, IdType: Clone, E, Ctx: Default, Encode, Config> Backend<Args> for CustomBackend<Args, DB, Fetch, Sink, IdType, Encode, Config>

where Fetch: Stream<Item = Result<Option<Task<Encode::Compact, Ctx, IdType>>, E>> + Send + 'static, Encode: Codec<Args> + Send + 'static, Encode::Error: Into<BoxDynError>, E: Into<BoxDynError>,

type IdType = IdType

The type used to uniquely identify tasks.

type Context = Ctx

Context associated with each task.

type Error = Box<dyn Error + Sync + Send>

The error type returned by backend operations

type Stream = Pin<Box<dyn Stream<Item = Result<Option<Task<Args, Ctx, IdType>>, Box<dyn Error + Sync + Send>>> + Send>>

A stream of tasks provided by the backend.

type Codec = Encode

The codec used for serialization/deserialization of tasks.

type Beat = Pin<Box<dyn Stream<Item = Result<(), <CustomBackend<Args, DB, Fetch, Sink, IdType, Encode, Config> as Backend<Args>>::Error>> + Send>>

A stream representing heartbeat signals.

type Layer = Identity

The type representing backend middleware layer.

fn heartbeat(&self, _: &WorkerContext) -> Self::Beat

Returns a heartbeat stream for the given worker.

fn middleware(&self) -> Self::Layer

Returns the backend’s middleware layer.

fn poll(self, worker: &WorkerContext) -> Self::Stream

Polls the backend for tasks for the given worker.

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

where DB: Debug, Config: Debug,

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

Formats the value using the given formatter.

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

where S: Sink<Task<Args, Ctx, IdType>>,

type Error = <S as Sink<Task<Args, Ctx, IdType>>>::Error

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, Ctx, IdType>, ) -> 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, IdType, Codec, Config> Unpin for CustomBackend<Args, DB, Fetch, Sink, IdType, Codec, Config>

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