Upstream Health Check and Circuit Breaker

Overview

Toron includes an Active Health Checker and 3-State Circuit Breaker (pkg/proxy) to protect gateway proxy routes from dispatching traffic to offline or degraded upstream microservices.

Circuit Breaker States

• Closed (Healthy): Target is operating normally. Requests and health probes succeed.
• Open (Tripped): Target has reached $N$ consecutive failures. Requests immediately skip this target.
• HalfOpen (Probing Recovery): After cooldown_period elapses, trial probes test target recovery. If successful, state resets to Closed.

Configuration in routes.yaml

routes:
  - type: "upstream"
    prefix: "/api"
    algorithm: "round_robin"
    targets:
      - "http://localhost:9001"
      - "http://localhost:9002"
    health_check_path: "/health"
    health_check_interval: 5s
    consecutive_failures: 3
    cooldown_period: 10s