Golang服务降级实现方法详解

ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
defer cancel()
result, err := externalService.Call(ctx)
if err != nil {
// 超时或错误，触发降级
return getFallbackData()
}
return result

var cb = &gobreaker.CircuitBreaker{
    StateMachine: gobreaker.NewStateMachine(gobreaker.Settings{
        Name:        "external-service",
        MaxRequests: 3,
        Interval:    10 * time.Second,
        Timeout:     30 * time.Second,
        ReadyToTrip: func(counts gobreaker.Counts) bool {
            return counts.ConsecutiveFailures > 5
        },
    }),
}
// 调用时
result, err := cb.Execute(func() (interface{}, error) {
return externalService.Call(context.Background())
})
if err != nil {
return getFallbackData() // 熔断期间直接降级
}

func getFallbackData() []UserData {
    if cached, ok := cache.Get("user_list"); ok {
        return cached.([]UserData)
    }
    return []UserData{} // 安全兜底
}

func DegradationMiddleware(cb *gobreaker.CircuitBreaker) gin.HandlerFunc {
    return func(c *gin.Context) {
        _, err := cb.Execute(func() (interface{}, error) {
            c.Next()
            return nil, nil
        })
        if err != nil {
            c.JSON(200, gin.H{"data": getDefaultResponse(), "msg": "service degraded"})
            c.Abort()
        }
    }
}