SagaStep

Immutable descriptor of a saga step with forward and compensation logic.

Each saga step consists of:

• A unique step identifier (string or enum wrapped in TypedValue)

• A forward action that produces a result (suspend function for async operations)

• An optional compensation action that can undo the forward action (suspend function)

• An idempotency flag indicating if the step is safe to retry

• An optional timeout for the forward action

• An optional retry policy for handling transient failures

Forward and Compensation Actions

The forward action receives the saga context and produces a result. The compensation action receives the result from the forward action, allowing it to use information from the successful execution to perform the compensation.

Both forward and compensation actions are suspend functions, allowing for non-blocking asynchronous operations using Kotlin coroutines.

Timeout Support

Steps can specify a timeout duration. If the forward action exceeds this timeout, a TimeoutCancellationException is thrown and compensation runs.

Retry Support

Steps can specify a retry policy to handle transient failures with exponential backoff. Retries are applied before compensation.

Example

SagaStep(
    step = TypedValue.fromEnum(OrderSteps.CHARGE_PAYMENT),
    timeout = 5.seconds,  // Timeout after 5 seconds
    retryPolicy = RetryPolicy.CONSERVATIVE,  // Retry on transient failures
    forward = { context ->
        paymentService.charge(context.amount)  // Can be a suspend call
        // Returns transaction ID
    },
    compensation = { transactionId ->
        paymentService.refund(transactionId)  // Can be a suspend call
    },
    idempotent = true  // Safe to retry if execution fails
)

Parameters