Operation Handlers

Operation handlers perform side effects and return typed results. They do not own workflow routing.

reserve.implement(
  (operation, order) => reservationService.reserve(
    order,
    idempotencyKey: operation.context.idempotencyKey,
  ),
);

A class may implement OperationHandler<I, O>, or an Operation may bind a concise callback through implement. Handlers belong in the product module, not in workflow code.

Rules

• Use context.idempotencyKey for every external write.
• Heartbeat long work; the lease is the liveness indicator.
• Classify failures as retryable or permanent.
• Do not start other workflows or respond to work from a handler. Return a result and let the workflow decide.

Retries

The runtime creates the next attempt. Manual retry through the service API creates a new attempt and keeps the idempotency key. Exhausted work appears in the dead-letter list.

See Also

• Operations
• Idempotency
• OperationHandler API