alice.pds.demo.boltless.dev
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1package metrics
2
3import (
4 "fmt"
5 "net/http"
6 "time"
7
8 "github.com/go-chi/chi/v5"
9)
10
11type statusRecorder struct {
12 http.ResponseWriter
13 status int
14}
15
16func (r *statusRecorder) WriteHeader(status int) {
17 r.status = status
18 r.ResponseWriter.WriteHeader(status)
19}
20
21func Middleware(next http.Handler) http.Handler {
22 return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
23 rec := &statusRecorder{ResponseWriter: w, status: http.StatusOK}
24 start := time.Now()
25
26 next.ServeHTTP(rec, r)
27
28 // use the matched route pattern to avoid high cardinality
29 routePattern := chi.RouteContext(r.Context()).RoutePattern()
30 if routePattern == "" {
31 routePattern = "unknown"
32 }
33
34 status := fmt.Sprintf("%d", rec.status)
35 duration := time.Since(start).Seconds()
36
37 HttpRequestsTotal.WithLabelValues(r.Method, routePattern, status).Inc()
38 HttpRequestDuration.WithLabelValues(r.Method, routePattern, status).Observe(duration)
39 })
40}