Module backend 

Core traits for interacting with backends

The core traits and types for backends, responsible for providing sources of tasks, handling their lifecycle, and exposing middleware for internal processing. The traits here abstract over different backend implementations, allowing for extensibility and interoperability.

Overview

• Backend: The primary trait representing a task source, defining methods for polling tasks, heartbeats, and middleware.
• TaskSink: An extension trait for backends that support pushing tasks.
• FetchById, Update, Reschedule: Additional traits for managing tasks.
• Vacuum, ResumeById, ResumeAbandoned: Traits for backend maintenance and task recovery.
• RegisterWorker, ListWorkers, ListTasks: Traits for worker management and task listing.
• WaitForCompletion: A trait for waiting on task completion and checking their status.

Default Implementations

The module includes several default backend implementations, such as:

• MemoryStorage: An in-memory backend for testing and lightweight use cases
• Pipe: A simple pipe-based backend for inter-thread communication
• CustomBackend: A flexible backend allowing custom functions for task management

Modules

codec

Utilities for encoding and decoding task arguments and results

custom

Custom Backend

guide

A guide to using the implementing a backend Guide for implementing backends

jsonjson

File based Backend using JSON

memory

In-memory backend based on channels

pipe

Pipe streams to backends

poll_strategy

Polling strategies for backends.

queue

Represents a queue in the backend

shared

Shared connection support for backends

Structs

Filter

Filter criteria for listing tasks

QueueInfo

Represents information about a specific queue in the backend

RunningWorker

Represents a worker currently registered with the backend

Statistic

Represents an overview of the backend including queues, workers, and statistics

TaskResult

Represents the result of a task execution

Enums

StatType

Statistics type

TaskSinkError

Error type for TaskSink operations

Traits

Backend

The Backend trait defines how workers get and manage tasks from a backend.

ConfigExt

Extension trait for accessing queue configuration

Expose

Allows exposing additional functionality from the backend

FetchById

Allows fetching a task by its ID

ListAllTasks

Allows listing tasks across all queues with optional filtering

ListQueues

Allows listing all queues available in the backend

ListTasks

Allows listing tasks with optional filtering

ListWorkers

Allows listing all workers registered with the backend

Metrics

Allows collecting metrics from the backend

RegisterWorker

Allows registering a worker with the backend

Reschedule

Allows rescheduling a task for later execution

ResumeAbandoned

Allows fetching multiple tasks by their IDs

ResumeById

Allows resuming a task by its ID

TaskSink

Extends Backend to allow pushing tasks into the backend

Update

Allows updating an existing task

Vacuum

Allows cleaning up resources in the backend

WaitForCompletion

Allows waiting for tasks to complete and checking their status

WeakTaskSink

Extends Backend to allow pushing tasks into the backend without requiring compile time constraints. By default the TaskSink trait requires TaskSink<Args>: Backend<Args> which can be restrictive in certain scenarios. This means you cannot push tasks of different argument types using the same backend instance. The WeakTaskSink trait relaxes this constraint, allowing pushing tasks of any argument type as long as they match the backend’s context and ID type. This is useful for dynamic task management scenarios where tasks of varying types need to be pushed into the same backend instance.

Type Aliases

TaskStream

Represents a stream for T.