Circuit Breaker Pattern — References

Supporting implementation and monitoring references for the circuit-breaker-pattern skill.

Quick Navigation

Reading Strategy

Start with implementation-patterns.md to understand how to build or adopt a circuit breaker. Then read monitoring-metrics.md to learn how to observe it in production.

Recommended sequence:

1. implementation-patterns.md — core state machine code, then library usage
2. monitoring-metrics.md — metrics, dashboards, and alerting

File Descriptions

implementation-patterns.md — Full TypeScript state machine implementation for CLOSED/OPEN/HALF_OPEN states. Covers the opossum npm library for Node.js, a NestJS interceptor wrapping the breaker, how to compose retries with circuit breaker, and a health check endpoint that surfaces breaker state.

monitoring-metrics.md — Production observability. State-change event logging, Prometheus counter and gauge definitions, a Grafana dashboard JSON snippet for circuit breaker visualization, a /health endpoint returning breaker status, and Prometheus alerting rules for sustained OPEN state.

Cross-Reference Map

implementation-patterns.md
  └── opossum library        → https://nodeshift.dev/opossum/
  └── NestJS interceptors    → ../../../nestjs/references/ (if present)
  └── retry composition      → see result-pattern skill for error handling

monitoring-metrics.md
  └── Prometheus metrics     → complements any service observability setup
  └── Grafana dashboard      → imports as JSON into Grafana
  └── Health check endpoint  → pairs with Kubernetes liveness/readiness probes