Struct RollbackEngine 

pub struct RollbackEngine { /* private fields */ }

Rollback engine for workflow failure recovery.

The rollback engine implements the Saga compensation pattern using DAG backward traversal to selectively roll back dependent tasks.

Implementations

impl RollbackEngine

pub fn new() -> Self

Creates a new rollback engine.

pub fn find_rollback_set( &self, workflow: &Workflow, failed_task: &TaskId, strategy: RollbackStrategy, ) -> Result<Vec<TaskId>, RollbackError>

Finds the set of tasks to roll back based on failure and strategy.

Uses reverse graph traversal starting from the failed task to find all dependent tasks. The rollback order is reverse execution order.

Arguments

• workflow - The workflow to analyze
• failed_task - The task that failed (rollback origin)
• strategy - Rollback strategy to apply

Returns

• Ok(Vec<TaskId>) - Tasks in rollback order (reverse execution)
• Err(RollbackError) - If traversal fails

Example

let engine = RollbackEngine::new();
let rollback_set = engine.find_rollback_set(
    &workflow,
    &TaskId::new("task_d"),
    RollbackStrategy::AllDependent
)?;

pub async fn execute_rollback( &self, workflow: &Workflow, tasks: Vec<TaskId>, workflow_id: &str, audit_log: &mut AuditLog, compensation_registry: &CompensationRegistry, ) -> Result<RollbackReport, RollbackError>

Executes rollback for a set of tasks.

Executes compensation actions for each task in rollback order. Tasks without compensation are skipped. Failed compensations are logged.

Arguments

• workflow - The workflow being rolled back
• tasks - Tasks to roll back (in rollback order)
• workflow_id - Workflow ID for audit logging
• audit_log - Audit log for recording rollback events
• compensation_registry - Registry containing compensation actions

Returns

• Ok(RollbackReport) - Report of rollback execution
• Err(RollbackError) - If critical failure occurs

pub fn validate_compensation_coverage( &self, workflow: &Workflow, ) -> CompensationReport

Validates compensation coverage for all tasks in workflow.

Reports which tasks have compensation actions defined and which don’t.

Arguments

• workflow - The workflow to validate

Returns

Compensation coverage report

Trait Implementations

impl Default for RollbackEngine

fn default() -> Self

Returns the “default value” for a type.