Saga Client - Server

A Saga ensures that either all steps in a process complete successfully or, if one fails, the system executes compensating transactions to undo the previous successful steps. Microservices.io Happy Path right arrow right arrow right arrow Failure Path right arrow Step B (fails) right arrow Compensate A right arrow Rollback state. Microservices.io Implementation Models

: A central "orchestrator" service coordinates all steps and handles failures in one place. saga client server

| Challenge | Description | Solution | | :--- | :--- | :--- | | | Client cannot see intermediate progress | Provide a GET /saga/id/status endpoint with current step | | Long-running locks | A flight seat held for hours while user pays | Implement "Timeout" steps in Saga. If timeout expires, auto-compensate | | Orchestrator failure | The Saga Server crashes mid-transaction | Persist state before each command. Upon restart, recover pending Sagas | | Poison messages | A Worker service always fails | Dead-letter queue + manual intervention endpoint for client | | Distributed tracing | Debugging cross-service calls | Pass TraceId from Client -> Saga Server -> Worker Services | A Saga ensures that either all steps in

To understand the Client-Server dynamic, you must choose your coordination style: | Challenge | Description | Solution | |

@RestController @RequestMapping("/saga") public class SagaController @PostMapping("/order") public ResponseEntity<SagaResponse> startSaga(@RequestBody OrderRequest request, @RequestHeader("Idempotency-Key") String idempKey) // 1. Check if already processed SagaInstance saga = sagaRepo.findByIdempKey(idempKey); if (saga != null) return ResponseEntity.ok(new SagaResponse(saga.getStatus()));

In modern server-side architectures, the Saga Pattern is a way to maintain data consistency in distributed systems . It breaks one large business transaction into a sequence of smaller "local transactions".

A Saga Client Server is an architectural pattern that enables communication between a client and a server in a distributed system. The term "Saga" was coined by Hector Garcia-Molina and Kenneth Salem in their 1987 paper "Sagas" [1]. The pattern is inspired by the concept of a saga, which refers to a long-running business process that consists of multiple, coordinated transactions.