Compensation

The process of handling failures in distributed workflows by emitting events that undo or mitigate effects of prior events.

When Compensation Occurs

1. Saga issues command to target aggregate
2. Target aggregate rejects the command
3. RejectionNotification sent to originating saga
4. Saga's source aggregate receives notification
5. Source aggregate emits compensation events

Flow Diagram

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│   Order     │     │    Saga     │     │  Inventory  │
│  Aggregate  │     │             │     │  Aggregate  │
└──────┬──────┘     └──────┬──────┘     └──────┬──────┘
       │                   │                   │
       │ OrderCreated      │                   │
       ├──────────────────►│                   │
       │                   │ ReserveStock     │
       │                   ├──────────────────►│
       │                   │                   │
       │                   │ REJECTED          │
       │                   │◄──────────────────┤
       │                   │                   │
       │ RejectionNotif    │                   │
       │◄──────────────────┤                   │
       │                   │                   │
       │ OrderCancelled    │                   │
       │ (compensation)    │                   │

SagaCommandOrigin

Tracks information needed for compensation routing:

• Saga name
• Triggering aggregate (domain, root)
• Triggering event sequence

Revocation

Response from compensation handlers indicating how to proceed:

• Continue with compensation
• Abort compensation flow
• Escalate to DLQ