别再只盯着CPU和内存了：用Prometheus + Grafana把业务真正跑起来的样子画出来

package main

import (
    "net/http"
    "time"

    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/promhttp"
)

var (
    orderTotal = prometheus.NewCounterVec(
        prometheus.CounterOpts{
            Name: "business_order_total",
            Help: "下单请求总数",
        },
        []string{"status", "channel"},
    )

    orderDuration = prometheus.NewHistogramVec(
        prometheus.HistogramOpts{
            Name:    "business_order_duration_seconds",
            Help:    "下单接口耗时",
            Buckets: []float64{0.05, 0.1, 0.2, 0.5, 1, 2, 5},
        },
        []string{"status"},
    )

    paymentSuccess = prometheus.NewCounter(
        prometheus.CounterOpts{
            Name: "business_payment_success_total",
            Help: "支付成功次数",
        },
    )
)

func init() {
    prometheus.MustRegister(orderTotal, orderDuration, paymentSuccess)
}

func createOrderHandler(w http.ResponseWriter, r *http.Request) {
    start := time.Now()
    status := "success"
    channel := r.URL.Query().Get("channel")
    if channel == "" {
        channel = "app"
    }

    // 模拟业务逻辑
    // ... 校验库存、创建订单、调用支付 ...

    // 假设支付成功
    paymentSuccess.Inc()

    orderTotal.WithLabelValues(status, channel).Inc()
    orderDuration.WithLabelValues(status).Observe(time.Since(start).Seconds())

    w.Write([]byte(`{"code":0,"msg":"ok"}`))
}

func main() {
    http.Handle("/metrics", promhttp.Handler())
    http.HandleFunc("/order/create", createOrderHandler)
    http.ListenAndServe(":8080", nil)
}

global:
  scrape_interval: 15s

scrape_configs:
  - job_name: 'business-order'
    static_configs:
      - targets: ['order-service-1:8080', 'order-service-2:8080']
    metrics_path: /metrics
    relabel_configs:
      - source_labels: [__address__]
        target_label: instance

sum(rate(business_payment_success_total[5m])) 
/ 
sum(rate(business_order_total{status="success"}[5m]))