oppi.li
bnewbold.net
+99
util/svcutil/metrics_middleware.go
+99
util/svcutil/metrics_middleware.go
···
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package svcutil
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import (
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"errors"
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"net/http"
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"strconv"
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"time"
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"github.com/labstack/echo/v4"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/client_golang/prometheus/promauto"
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)
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var reqSz = promauto.NewHistogramVec(prometheus.HistogramOpts{
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Name: "http_request_size_bytes",
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Help: "A histogram of request sizes for requests.",
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Buckets: prometheus.ExponentialBuckets(100, 10, 8),
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}, []string{"code", "method", "path"})
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var reqDur = promauto.NewHistogramVec(prometheus.HistogramOpts{
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Name: "http_request_duration_seconds",
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Help: "A histogram of latencies for requests.",
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Buckets: prometheus.ExponentialBuckets(0.001, 2, 15),
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}, []string{"code", "method", "path"})
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var reqCnt = promauto.NewCounterVec(prometheus.CounterOpts{
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Name: "http_requests_total",
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Help: "A counter for requests to the wrapped handler.",
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}, []string{"code", "method", "path"})
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var resSz = promauto.NewHistogramVec(prometheus.HistogramOpts{
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Name: "http_response_size_bytes",
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Help: "A histogram of response sizes for requests.",
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Buckets: prometheus.ExponentialBuckets(100, 10, 8),
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}, []string{"code", "method", "path"})
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// MetricsMiddleware defines handler function for metrics middleware
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func MetricsMiddleware(next echo.HandlerFunc) echo.HandlerFunc {
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return func(c echo.Context) error {
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path := c.Path()
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if path == "/metrics" || path == "/_health" {
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return next(c)
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}
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start := time.Now()
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requestSize := computeApproximateRequestSize(c.Request())
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err := next(c)
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status := c.Response().Status
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if err != nil {
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var httpError *echo.HTTPError
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if errors.As(err, &httpError) {
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status = httpError.Code
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}
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if status == 0 || status == http.StatusOK {
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status = http.StatusInternalServerError
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}
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}
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elapsed := float64(time.Since(start)) / float64(time.Second)
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statusStr := strconv.Itoa(status)
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method := c.Request().Method
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responseSize := float64(c.Response().Size)
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reqDur.WithLabelValues(statusStr, method, path).Observe(elapsed)
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reqCnt.WithLabelValues(statusStr, method, path).Inc()
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reqSz.WithLabelValues(statusStr, method, path).Observe(float64(requestSize))
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resSz.WithLabelValues(statusStr, method, path).Observe(responseSize)
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return err
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}
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}
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func computeApproximateRequestSize(r *http.Request) int {
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s := 0
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if r.URL != nil {
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s = len(r.URL.Path)
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}
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s += len(r.Method)
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s += len(r.Proto)
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for name, values := range r.Header {
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s += len(name)
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for _, value := range values {
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s += len(value)
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}
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}
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s += len(r.Host)
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// N.B. r.Form and r.MultipartForm are assumed to be included in r.URL.
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if r.ContentLength != -1 {
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s += int(r.ContentLength)
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}
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return s
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}