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Stability (Sentinel)

Goals: Flow limiting and Circuit breaking / Degrade.
Rules are centrally managed and delivered via Nacos.
Reads use short-TTL cache; writes fail fast (429/503) to avoid cascading failures.

1. Centralized Rule Governance

  • Rule source: delivered uniformly from Nacos Config Center; resource names match code for easy troubleshooting and rollback.
  • Guidance: apply short-TTL cache for read APIs; set fast-fail thresholds for write APIs to shorten recovery time.

2. Rate Limiting: Trigger Logs

  • When FlowException is triggered, log a clear blocked record including resource name / trigger origin, etc.
  • Gateway/core services can provide different fallbacks based on the resource name.

3. Rate Limiting: Test Results

  • Observe pass/reject QPS, concurrency, avg RT, and per-minute pass/reject metrics.
  • Verify that the load test method and thresholds meet expectations (don’t drag down the main flow).

4. Circuit Breaking / Degrade: Trigger Logs

  • Record the reason when DegradeException is triggered or a fallback executes to quickly locate the source.
  • Recommendation: isolate rollback/retry paths from the main flow to avoid avalanche effects.

5. Circuit Breaking: Test Results

  • For key resources, monitor degrade count/duration, avg RT, and success rate to ensure no spread, no amplification.
  • Convention: Fallback/BlockHandler for integration / task-dispatch APIs are aggregated in the Service layer (thin Controller).
  • Resource names follow a unified convention (consistent with rules); inject traceId into logs to enable trace ↔ log cross-checks.