feat: Successfully validated the implementation of Phase 3

[edsonwade]

• Summary:

  1. Primary Request and Intent:
     The user asked to execute the skill phase-3-advanced-patterns.md at C:\Users\HP\.claude\projects\e-commerce-microservice\.claude\skills\refactoring\phase-3-advanced-patterns.md
     exactly as described. Key constraints:

     • Do NOT assume anything, do NOT resume without verification
     • Always test after changing or creating new features (unit, controller, integration, BDD Cucumber)
     • Do NOT create a custom plan — follow the skill exactly
     • Mandatory: Read and execute the related skills first: solid-principles, design-patterns, clean-code, java-code-review, test-quality
     • Code must follow all standard pattern skills or it will be rejected

  2. Key Technical Concepts:

     • Server-Sent Events (SSE): Spring SseEmitter, MediaType.TEXT_EVENT_STREAM_VALUE, @EventListener, ConcurrentHashMap for emitter registry
     • Spring Application Events: ApplicationEventPublisher.publishEvent(), @EventListener — intra-JVM, no serialization overhead
     • Choreography Saga: order-service status machine (REQUESTED → CONFIRMED/CANCELLED/TIMEOUT)
     • Saga Terminal States: CONFIRMED, CANCELLED, TIMEOUT — cause SSE stream to complete automatically
     • Gateway SSE routing: SSE route must appear BEFORE generic route; no circuit breaker or retry (both break long-lived SSE streams); metadata.response-timeout: 300000 (5 min);
       X-Accel-Buffering: no header
     • Outbox Pattern: OutboxEvent + OutboxEventPublisher for at-least-once Kafka delivery
     • Grafana + Prometheus: Saga visibility dashboard, alert rules for high failure rate / timeout spike / outbox backlog
     • Spring Cloud Config Server: all service configurations live in config-service/src/main/resources/configurations/
     • Multi-tenancy: TenantContext propagation across services
     • JUnit 5 + AssertJ + Mockito: test patterns used throughout
     • @RequiredArgsConstructor (Lombok): generates constructor from all final fields — adding a new field changes the constructor signature

  3. Files and Code Sections:

     • NEW: order-service/src/main/java/code/with/vanilson/orderservice/event/OrderStatusChangedEvent.java

       • Spring in-process event record published whenever saga updates an order status; consumed by SSE controller

       package code.with.vanilson.orderservice.event;
       import java.time.Instant;
       public record OrderStatusChangedEvent(
               String correlationId,
               String status,
               String orderReference,
               Instant occurredAt
       ) {}

     • MODIFIED: order-service/src/main/java/code/with/vanilson/orderservice/kafka/OrderSagaConsumer.java

       • Added ApplicationEventPublisher eventPublisher field (injected via @RequiredArgsConstructor)
       • Added import code.with.vanilson.orderservice.event.OrderStatusChangedEvent, org.springframework.context.ApplicationEventPublisher, java.time.Instant
       • After each orderService.updateStatus() call, publishes OrderStatusChangedEvent:
         • onPaymentAuthorized: publishes CONFIRMED event
         • onPaymentFailed: publishes CANCELLED event
         • onInventoryInsufficient: publishes INVENTORY_INSUFFICIENT, then CANCELLED

       private final OrderService             orderService;
       private final OrderProducer            orderProducer;
       private final MessageSource            messageSource;
       private final MeterRegistry            meterRegistry;
       private final ApplicationEventPublisher eventPublisher;
       // ...
       orderService.updateStatus(event.correlationId(), OrderStatus.CONFIRMED);
       eventPublisher.publishEvent(new OrderStatusChangedEvent(
               event.correlationId(), OrderStatus.CONFIRMED.name(),
               event.orderReference(), Instant.now()));

     • MODIFIED: order-service/src/main/java/code/with/vanilson/orderservice/scheduler/SagaTimeoutScheduler.java

       • Added ApplicationEventPublisher eventPublisher field
       • After orderRepository.save(order) and metric increment, publishes TIMEOUT event

       private final OrderRepository          orderRepository;
       private final MeterRegistry            meterRegistry;
       private final ApplicationEventPublisher eventPublisher;
       // ...
       order.setStatus(OrderStatus.TIMEOUT);
       orderRepository.save(order);
       meterRegistry.counter("saga.timeout.count").increment();
       eventPublisher.publishEvent(new OrderStatusChangedEvent(
               order.getCorrelationId(), OrderStatus.TIMEOUT.name(),
               order.getReference(), Instant.now()));

     • NEW: order-service/src/main/java/code/with/vanilson/orderservice/OrderStatusSseController.java

       • SSE streaming controller at same package level as OrderController
       • GET /api/v1/orders/{correlationId}/events → returns SseEmitter with 5-min timeout
       • @EventListener onOrderStatusChanged() → forwards event to connected emitter; completes on terminal status

       @Slf4j
       @RestController
       @RequestMapping("/api/v1/orders")
       @Tag(name = "Order SSE API", ...)
       public class OrderStatusSseController {
           private static final long SSE_TIMEOUT_MS = 300_000L;
           private static final Set<String> TERMINAL_STATUSES = Set.of("CONFIRMED", "CANCELLED", "TIMEOUT");
           private final Map<String, SseEmitter> emitters = new ConcurrentHashMap<>();
       
           @PreAuthorize("isAuthenticated()")
           @GetMapping(value = "/{correlationId}/events", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
           public SseEmitter streamOrderStatus(@PathVariable String correlationId) {
               SseEmitter emitter = new SseEmitter(SSE_TIMEOUT_MS);
               emitters.put(correlationId, emitter);
               emitter.onCompletion(() -> emitters.remove(correlationId));
               emitter.onTimeout(() -> emitters.remove(correlationId));
               emitter.onError(ex -> emitters.remove(correlationId));
               return emitter;
           }
       
           @EventListener
           public void onOrderStatusChanged(OrderStatusChangedEvent event) {
               SseEmitter emitter = emitters.get(event.correlationId());
               if (emitter == null) return;
               try {
                   emitter.send(SseEmitter.event().name("status-update").data(event));
                   if (TERMINAL_STATUSES.contains(event.status())) {
                       emitter.complete();
                   }
               } catch (IOException e) {
                   emitters.remove(event.correlationId());
               }
           }
       }

     • MODIFIED: order-service/src/main/java/code/with/vanilson/orderservice/config/OrderSecurityConfig.java

       • Added explicit SSE endpoint matcher before anyRequest().authenticated()

       .requestMatchers("/api/v1/orders/*/events").authenticated()
       .anyRequest().authenticated()

     • MODIFIED: config-service/src/main/resources/configurations/gateway-service.yml

       • Added order-service-sse route BEFORE generic order-service route (predicate specificity matters)
       • No circuit breaker, no retry — both break SSE streams
       • metadata.response-timeout: 300000 (5 min), connect-timeout: 5000
       • Headers: Cache-Control: no-cache, X-Accel-Buffering: no

       - id: order-service-sse
         uri: lb://ORDER-SERVICE
         predicates:
           - Path=/api/v1/orders/*/events
         metadata:
           response-timeout: 300000
           connect-timeout: 5000
         filters:
           - AddResponseHeader=API-Version, v1
           - AddResponseHeader=Cache-Control, no-cache
           - AddResponseHeader=X-Accel-Buffering, no

     • NEW: config-service/src/main/resources/grafana/dashboards/saga-visibility.json

       • 7-panel Grafana dashboard for saga choreography visibility
       • Panels: Saga Success Rate (gauge), Step Rate success vs failure (time series), Saga Timeouts 5m (stat), Outbox Queue Depth (time series with threshold at 100), Outbox Publish
         Rate (time series), Customer Snapshot Coverage (gauge), Saga Timeouts Over Time (time series)
       • Metrics used: saga_step_completed_total, saga_timeout_count_total, outbox_queue_depth, outbox_publish_count_total, customer_resolve_count_total
       • Dashboard UID: saga-visibility-v1, refresh 30s, tagged saga, order-service, observability

     • MODIFIED: config-service/src/main/resources/prometheus/alert.rules.yml

       • Added saga alert group with 3 rules:

         - alert: SagaHighFailureRate    # >5% failure rate for 5m, severity: warning
         - alert: SagaTimeoutSpike       # >10 timeouts in 5m window, severity: warning
         - alert: OutboxQueueBacklog     # outbox_queue_depth > 100 for > 2m, severity: critical

     • NEW: order-service/src/test/java/code/with/vanilson/orderservice/sse/OrderStatusSseControllerTest.java

       • 8 unit tests (no Spring context needed — plain instantiation)
       • StreamOrderStatus nested class: returns non-null emitter, distinct emitters per correlationId, replaces on reconnect
       • OnOrderStatusChanged nested class: sends without throwing, ignores unknown correlationId, completes on CONFIRMED/CANCELLED/TIMEOUT, allows subsequent events after
         non-terminal status

     • MODIFIED: order-service/src/test/java/code/with/vanilson/orderservice/kafka/OrderSagaConsumerTest.java

       • Added @Mock ApplicationEventPublisher eventPublisher
       • Added import OrderStatusChangedEvent, ApplicationEventPublisher
       • 3 new test methods:
         • shouldPublishConfirmedEvent() — captures OrderStatusChangedEvent, asserts correlationId=CORRELATION_ID, status=CONFIRMED, orderReference=ORD-001
         • shouldPublishCancelledEvent() — same for payment failed path
         • shouldPublishIntermediateAndTerminalEvents() — verifies times(2) publish with INVENTORY_INSUFFICIENT then CANCELLED

     • MODIFIED: order-service/src/test/java/code/with/vanilson/orderservice/scheduler/SagaTimeoutSchedulerTest.java

       • Added @Mock ApplicationEventPublisher eventPublisher
       • Updated shouldDoNothingWhenNoStuckOrdersFound to also verify eventPublisher never called
       • Added shouldPublishTimeoutEventForEachStuckOrder():
         • Sets up 2 stuck orders with correlationIds corr-timeout-1, corr-timeout-2 and references ORD-T001, ORD-T002
         • Verifies eventPublisher called times(2), both with status TIMEOUT
         • Asserts correlationIds present in any order

     • MODIFIED: order-service/src/test/java/code/with/vanilson/orderservice/bdd/OrderSagaStepDefinitions.java

       • Fixed compilation error: added ApplicationEventPublisher mock to match updated constructor

       var eventPublisher = Mockito.mock(org.springframework.context.ApplicationEventPublisher.class);
       consumer = new OrderSagaConsumer(orderService, orderProducer, messageSource, meterRegistry, eventPublisher);

  4. Errors and Fixes:

     • Compilation error in OrderSagaStepDefinitions.java:
       • Error: constructor OrderSagaConsumer cannot be applied to given types; required: OrderService, OrderProducer, MessageSource, MeterRegistry, ApplicationEventPublisher; found: ...(4 args)
       • Root cause: OrderSagaConsumer uses @RequiredArgsConstructor (Lombok), so adding ApplicationEventPublisher as a 5th final field changed the constructor signature. The BDD
         step definition created OrderSagaConsumer manually with only 4 args.
       • Fix: Added var eventPublisher = Mockito.mock(org.springframework.context.ApplicationEventPublisher.class); and passed it as 5th arg to the constructor in
         OrderSagaStepDefinitions.setUp()

  5. Problem Solving:

     • SSE route ordering in gateway: SSE route must appear BEFORE the generic order-service route (Path=/api/v1/orders/**) otherwise the generic predicate matches first. Added
       as order-service-sse specifically before the generic route.
     • No circuit breaker/retry for SSE: Circuit breaker would interrupt long-lived SSE streams; retry would attempt to restart a streaming connection that's intentionally kept
       open. These were explicitly omitted from the SSE route.
     • No monitoring/ directory: The project stores Prometheus/Grafana configs inside config-service/src/main/resources/ not a top-level monitoring/ directory. Dashboard was
       created at config-service/src/main/resources/grafana/dashboards/saga-visibility.json.
     • Controller package placement: No presentation/ subdirectory exists in order-service — OrderController is at root package code.with.vanilson.orderservice.
       OrderStatusSseController was placed at the same root level.
     • orderReference availability: Confirmed that all three Kafka events (PaymentAuthorizedEvent, PaymentFailedEvent, InventoryInsufficientEvent) have orderReference
       field — no null needed.

  6. All User Messages:

     • Session start message: "Nice! skill phase-2-decouple-sync-calls.md builded with success. Next skill to execute is phase-3-advanced-patterns.md path
       C:\Users\HP\.claude\projects\e-commerce-microservice\.claude\skills\refactoring\phase-3-advanced-patterns.md. execute as it describe in skill follow all the insctruction mention in
       the skill. Do not assume, do not resume, Always test after changing or create new feature in the codebase (unit test, controller, integration and bdd cucumber). # Warning: Do not
       create your own plan. Follow the skill phase-2-decouple-sync-calls exactly as it describe, but read first the codebase to understand it before change. ## Mandatory Read always the
       Related Skills and execute in corrent building code. The code need allways follow and execute these standard pattern skill, otherwise will be rejected."

  7. Pending Tasks:

     • Phase 3 is now fully complete (79 tests, 0 failures).
     • No explicit next task was mentioned by the user beyond Phase 3.
     • Phase 4 (SaaS multi-tenancy) exists per project memory but was not requested.

  8. Current Work:
     Phase 3 — Advanced Patterns was fully implemented and verified:

     • All 4 steps executed per skill definition
     • Step 1 (SSE): 6 files created/modified, gateway route added
     • Step 2 (Dashboard): Grafana JSON + Prometheus alert rules added
     • Steps 3 & 4: Documentation-only, no code changes required
     • Final test run: 79 tests, 0 failures, 0 errors, 0 skipped
     • BDD compilation error found and fixed (missing ApplicationEventPublisher mock in step definitions)

  9. Optional Next Step:
     Phase 3 is complete. The user's message stated: "Next skill to execute is phase-3-advanced-patterns.md" — this work is done.