redis_task_queue 0.4.1

A small Redis-backed task queue for server-side Dart. Enqueue or schedule jobs and process them in a worker with retries, a dead-letter list, and weighted queues.

0.4.1

• Docs: replace the two README mermaid diagrams with rendered PNGs. pub.dev does not render mermaid, so the diagrams showed as raw source there; they now display as images on both pub.dev and GitHub.

0.4.0

• Add observability hooks to Worker.connect. onError fires on every handler failure, with the 1-based attempt number and whether a retry follows; onDeadLetter fires when a task is given up on after its retries. Both default to null and are isolated, so a throwing callback cannot take the worker down. Before this, a handler exception was swallowed silently, which is rarely what a production queue wants.
• Restore scheduled tasks (enqueue with processAt or processIn), which the 0.3.1 release removed by accident. 0.3.1 was published as a docs-only change but also dropped the 0.3.0 scheduling feature; if you schedule tasks for a future time, move to 0.4.0 (or pin 0.3.0) rather than 0.3.1.

0.3.0

• Scheduled tasks. enqueue takes an optional processAt (an absolute time) or processIn (a delay from now), set at most one, to hold a task until a future time.
• No new machinery: a scheduled task is scored into the same per-queue delayed sorted set the 0.2.0 retry backoff uses, and the same atomic Lua due-mover promotes it once due. The worker is unchanged.
• The inherited bounds apply: a due task starts up to about a second past its due time (the mover runs once per poll-loop pass), and only while a worker polling that queue is running.
• enqueue without either parameter behaves exactly as in 0.2.0.

0.2.0

• Exponential backoff for retries. A failed task is no longer re-enqueued immediately: it goes into a per-queue delayed sorted set (<prefix>:<queue>:delayed) scored with the time it becomes due, and waits min(cap, base * 2^(retry-1)) plus jitter before being retried.
• Configurable backoff on Worker.connect: backoffBase (default 1s), backoffCap (default 60s), and backoffJitter (default 0.1).
• The worker's poll loop now runs a due-mover each pass that promotes delayed tasks whose score has passed back onto their pending list. The move is a single atomic Redis Lua script (ZRANGEBYSCORE + ZREM + LPUSH), so a task can't be lost or duplicated, even with multiple workers.
• Dead-letter behaviour is unchanged; weighted-queue behaviour is unchanged.

0.1.0

• Initial release.
• Enqueue tasks from a producer, process them in a worker.
• Retries with a dead-letter list after maxRetries.
• Weighted queues to avoid starvation.