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Sentinel Plugin

lynx-sentinel brings flow control, circuit breaking, system protection, and built-in metrics into Lynx. The implementation is much richer than the old introductory doc: besides loading static rules, it exposes convenience APIs for guarded execution, dynamic rule updates, middleware/interceptor creation, and dashboard access.

Runtime facts​

ItemValue
Go modulegithub.com/go-lynx/lynx-sentinel
Config prefixlynx.sentinel
Runtime plugin namesentinel.flow_control
Main gettersGetSentinel(), GetMetrics(), GetDashboardURL()

What the implementation actually provides​

  • loads flow rules, circuit breaker rules, system rules, metrics, and dashboard configuration from lynx.sentinel
  • exposes convenience APIs such as Entry, EntryWithContext, Execute, ExecuteWithContext, and CheckFlow
  • supports runtime rule management through AddFlowRule, RemoveFlowRule, AddCircuitBreakerRule, RemoveCircuitBreakerRule, and ReloadRules
  • exposes monitoring helpers including GetMetrics, GetResourceStats, GetAllResourceStats, and GetCircuitBreakerState
  • can create framework-facing guards through CreateHTTPMiddleware() and CreateGRPCInterceptor()

Configuration​

lynx:
  sentinel:
    enabled: true
    app_name: "user-service"
    log_level: "info"
    log_dir: "./logs/sentinel"
    flow_rules:
      - resource: "/api/users"
        threshold: 100
        token_calculate_strategy: "direct"
        control_behavior: "reject"
        enabled: true
    circuit_breaker_rules:
      - resource: "/api/orders"
        strategy: "error_ratio"
        threshold: 0.5
        min_request_amount: 10
        retry_timeout_ms: 5000
        enabled: true
    system_rules:
      - metric_type: "load"
        threshold: 2.0
        strategy: "bbr"
        enabled: true
    metrics:
      enabled: true
      interval: "1s"
    dashboard:
      enabled: true
      port: 8719

What The Official Template Uses​

The official template does not enable Sentinel by default.

That matches the role of the plugin:

  • Sentinel is a runtime protection layer, not a minimum boot dependency
  • you normally add it after HTTP or gRPC resources and route names are stable
  • this page therefore needs to be read as "how to add guarded traffic control to a running service", not "what every new Lynx project starts with"

Usage​

import sentinel "github.com/go-lynx/lynx-sentinel"

func guarded() error {
    return sentinel.Execute("create-user", func() error {
        return doBusiness()
    })
}

HTTP middleware and gRPC interceptor are also first-class APIs:

middleware, err := sentinel.CreateHTTPMiddleware(func(req interface{}) string {
    return req.(*http.Request).URL.Path
})

interceptor, err := sentinel.CreateGRPCInterceptor()

Practical guidance​

  • define stable resource names first, otherwise rule tuning becomes noise
  • use dynamic rule APIs only if your team has clear ownership over protection policy changes
  • if you enable the dashboard, treat it as an operational endpoint rather than a public feature