redis_task_queue library

A small Redis-backed task queue for server-side Dart.

Enqueue work from your request path with QueueClient, immediately or scheduled for a future time, and process it in a separate Worker with retries, a dead-letter list, and weighted queues.

Classes

DeadLetter

A task that exhausted its retries and is parked on the dead-letter list, together with why it failed.

QueueClient

Enqueues tasks onto Redis. Safe to keep one client for the lifetime of your app and reuse it: enqueuing is a single LPUSH (a single ZADD for a scheduled task). A dropped connection doesn't end that lifetime either: the next call reconnects and retries once before giving up, so a Redis restart or failover doesn't permanently break a client that survives it.

QueueStats

A snapshot of how much work is sitting in the queue right now.

Task

A unit of work to run outside the request path.

TaskContext

What the worker knows about the run in progress, handed to a handler alongside the task.

Worker

Consumes tasks from Redis and runs their handlers.

Typedefs

TaskDeadLetterCallback = void Function(Task task, TaskContext context, Object error, StackTrace stackTrace)

Called when a task has exhausted its retries and been moved to the dead-letter list.

TaskErrorCallback = void Function(Task task, TaskContext context, Object error, StackTrace stackTrace)

Called each time a task handler throws, before the worker decides what to do next.

TaskHandler = FutureOr<void> Function(Task task, TaskContext context)

A handler processes one task type. Throwing signals failure, which triggers a retry (up to the envelope's maxRetries); returning normally marks it done.

Exceptions / Errors

TaskQueueConnectionException

Redis could not be reached, or the connection died mid-command.

TaskQueueException

The base type for every failure this package reports.

TaskQueueServerException

Redis received the command and answered with an error.