Attribute Macro durable 

#[durable]

Makes an async function durable by wrapping it with checkpoint-based caching.

The macro automatically:

• Checks for existing checkpoint before execution
• Returns cached result if checkpoint exists
• Executes function and saves result as checkpoint if no cache

Requirements

• Function must be async
• First parameter is the idempotency key (any type that implements Display)
• Function must return Result<T, E> where T: Serialize + DeserializeOwned
• SDK must be registered via RuntaraSdk::init() before calling

Example

use runtara_sdk::durable;

#[durable]
pub async fn fetch_order(key: &str, order_id: &str) -> Result<Order, OrderError> {
    // The key determines caching - same key = same cached result
    db.fetch_order(order_id).await
}

// Usage:
fetch_order("order-123", "123").await