vendor/github.com/go-kit/kit/examples/stringsvc2/instrumenting.go

   1 package main
   2
   3 import (
   4         "fmt"
   5         "time"
   6
   7         "github.com/go-kit/kit/metrics"
   8 )
   9
  10 type instrumentingMiddleware struct {
  11         requestCount   metrics.Counter
  12         requestLatency metrics.Histogram
  13         countResult    metrics.Histogram
  14         next           StringService
  15 }
  16
  17 func (mw instrumentingMiddleware) Uppercase(s string) (output string, err error) {
  18         defer func(begin time.Time) {
  19                 lvs := []string{"method", "uppercase", "error", fmt.Sprint(err != nil)}
  20                 mw.requestCount.With(lvs...).Add(1)
  21                 mw.requestLatency.With(lvs...).Observe(time.Since(begin).Seconds())
  22         }(time.Now())
  23
  24         output, err = mw.next.Uppercase(s)
  25         return
  26 }
  27
  28 func (mw instrumentingMiddleware) Count(s string) (n int) {
  29         defer func(begin time.Time) {
  30                 lvs := []string{"method", "count", "error", "false"}
  31                 mw.requestCount.With(lvs...).Add(1)
  32                 mw.requestLatency.With(lvs...).Observe(time.Since(begin).Seconds())
  33                 mw.countResult.Observe(float64(n))
  34         }(time.Now())
  35
  36         n = mw.next.Count(s)
  37         return
  38 }