taskworker

A taskworker is a component in a software system that executes discrete units of work asynchronously. It typically runs in the background as a separate thread, process, or container, and consumes tasks from a queue or scheduler. Each task represents a small unit of work with a defined payload and objective, such as sending an email, resizing an image, or processing a data record.

In operation, a taskworker continually polls or is notified of available tasks, retrieves one or more tasks, and performs the required computation. After completion, it reports the result and acknowledges the task to the queue. Taskworkers are often part of a larger task queue or job queue system and can be deployed in groups to scale horizontally. Concurrency, retry behavior, and timeouts are common configuration aspects. Many implementations support pre- and post-processing hooks, monitoring, and metrics.

Reliability and delivery semantics are important considerations. Tasks may be delivered at-least-once or exactly-once, depending on the system’s guarantees. Features such as retry with backoff, dead-letter queues for failed tasks, and visibility timeouts help manage failures and prevent duplicate work. Idempotency—that is, ensuring repeated executions have the same effect as a single execution—is frequently recommended.

Scalability and deployment patterns favor stateless taskworkers that can be added or removed to match load. They are commonly used to handle long-running or CPU- or IO-intensive work without blocking the main application flow. Popular environments include Python with Celery, Ruby with Sidekiq, Java with various executors, and cloud-based queues that dispatch tasks to workers. Design considerations include language limitations, task design, and observability.