Files
2026-07-14 10:24:10 +08:00

65 lines
1.8 KiB
Go

package middleware
import (
"strconv"
"time"
"github.com/gin-gonic/gin"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promauto"
)
// #18 Prometheus 指标。三个标配:
// - http_requests_total: 请求计数(按 method/route/status 维度)
// - http_request_duration_seconds: 请求耗时直方图(按 method/route 维度)
// - http_requests_in_flight: 当前在飞请求数
var (
httpRequestsTotal = promauto.NewCounterVec(
prometheus.CounterOpts{
Name: "http_requests_total",
Help: "HTTP 请求总数。",
},
[]string{"method", "route", "status"},
)
httpRequestDuration = promauto.NewHistogramVec(
prometheus.HistogramOpts{
Name: "http_request_duration_seconds",
Help: "HTTP 请求耗时(秒)。",
Buckets: prometheus.DefBuckets,
},
[]string{"method", "route"},
)
httpRequestsInFlight = promauto.NewGauge(
prometheus.GaugeOpts{
Name: "http_requests_in_flight",
Help: "正在处理的 HTTP 请求数。",
},
)
)
// Metrics Prometheus 指标中间件(#18)。记录请求计数、耗时、在飞数。
// route 标签用 c.FullPath()(路由模板,如 /api/v1/users/:id),避免高基数。
func Metrics() gin.HandlerFunc {
return func(c *gin.Context) {
httpRequestsInFlight.Inc()
defer httpRequestsInFlight.Dec() // M2 修复:defer 保证 panic 时也递减,不依赖 Recover 中间件顺序
start := time.Now()
c.Next()
elapsed := time.Since(start).Seconds()
status := strconv.Itoa(c.Writer.Status())
route := c.FullPath()
if route == "" {
route = "not_found"
}
method := c.Request.Method
httpRequestsTotal.WithLabelValues(method, route, status).Inc()
httpRequestDuration.WithLabelValues(method, route).Observe(elapsed)
}
}