vendor/github.com/go-kit/kit/examples/stringsvc3/instrumenting.go

   1 package main
   2
   3 import (
   4         "fmt"
   5         "time"
   6
   7         "github.com/go-kit/kit/metrics"
   8 )
   9
  10 func instrumentingMiddleware(
  11         requestCount metrics.Counter,
  12         requestLatency metrics.Histogram,
  13         countResult metrics.Histogram,
  14 ) ServiceMiddleware {
  15         return func(next StringService) StringService {
  16                 return instrmw{requestCount, requestLatency, countResult, next}
  17         }
  18 }
  19
  20 type instrmw struct {
  21         requestCount   metrics.Counter
  22         requestLatency metrics.Histogram
  23         countResult    metrics.Histogram
  24         StringService
  25 }
  26
  27 func (mw instrmw) Uppercase(s string) (output string, err error) {
  28         defer func(begin time.Time) {
  29                 lvs := []string{"method", "uppercase", "error", fmt.Sprint(err != nil)}
  30                 mw.requestCount.With(lvs...).Add(1)
  31                 mw.requestLatency.With(lvs...).Observe(time.Since(begin).Seconds())
  32         }(time.Now())
  33
  34         output, err = mw.StringService.Uppercase(s)
  35         return
  36 }
  37
  38 func (mw instrmw) Count(s string) (n int) {
  39         defer func(begin time.Time) {
  40                 lvs := []string{"method", "count", "error", "false"}
  41                 mw.requestCount.With(lvs...).Add(1)
  42                 mw.requestLatency.With(lvs...).Observe(time.Since(begin).Seconds())
  43                 mw.countResult.Observe(float64(n))
  44         }(time.Now())
  45
  46         n = mw.StringService.Count(s)
  47         return
  48 }