Go API 监控

使用 prometheus_client 暴露 API metrics,对接 promethues 之后可以很方便的监控 API 调用情况,调用耗时、状态码等等。因为 Prometheus 是 pull 的模式,所以服务很好解耦,不会依赖 promethues server。

prometheus/client_golang 是 Go 的客户端。对于 gin,你可以写一个中间件来完成 API 耗时统计:

var (
    APICalledLatency = prometheus.NewSummaryVec(
        prometheus.SummaryOpts{
            Namespace: "",
            Subsystem: "",
            Name: "api_called_latency",
            Help: "Latency in microseconds",
        },
        []string{"api", "method", "status_code"},
    )
)

func init() {
    prometheus.MustRegister(APICalledLatency)
}

func metricsExport() gin.HandlerFunc {
    return func(c *gin.Context) {
        start := time.Now()
        defer func() {
            cost := time.Since(start).Nanoseconds()
            api := c.Request.URL.Path
            method := c.Request.Method
            status := strconv.Itoa(c.Writer.Status())

            // set ignore itself in here
            if api == "/metrics" {
                return
            }

            APICalledLatency.WithLabelValues(api, method, status).Observe(float64(cost))
        }()

        c.Next()
    }
}

因为 gin 的 Handler 不是标准库的 ServeHTTP(ResponseWriter, *Request) ,但是它提供了一个转换函数,我们可以这样:

r.GET("/metrics", gin.WrapH(promhttp.Handler()))

First created: 2020-03-17 16:32:37
Last updated: 2021-11-15 Mon 10:18
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