Idempotent

Marker for steps that are safe to retry (idempotent operations).

When marked idempotent, the saga executor knows the step can be safely retried without side effects if execution fails and is restarted.

Idempotency

An operation is idempotent if it produces the same result when executed multiple times. Examples:

• Idempotent: Setting a value, deleting a resource, querying data

• Not idempotent: Incrementing a counter, creating a new resource, charging payment

Usage Example

@Idempotent
fun updateOrderStatus(orderId: String, status: String) {
    // This operation is idempotent - calling it multiple times
    // with the same parameters produces the same result
    orderRepository.setStatus(orderId, status)
}

saga.step("update-status") { context ->
    updateOrderStatus(context.orderId, "CONFIRMED")
}
.idempotent(true)  // Mark as idempotent at runtime

Runtime Marking

Steps can be marked idempotent at runtime using the idempotent() DSL method:

step("set-status") { context ->
    statusService.set(context.orderId, "PROCESSING")
}
.idempotent(true)