package main
import (
"time"
"github.com/go-kit/kit/examples/addsvc/server"
"github.com/go-kit/kit/log"
"github.com/go-kit/kit/metrics"
)
type pureAddService struct{}
func (pureAddService) Sum(a, b int) int { return a + b }
func (pureAddService) Concat(a, b string) string { return a + b }
type loggingMiddleware struct {
server.AddService
log.Logger
}
func (m loggingMiddleware) Sum(a, b int) (v int) {
defer func(begin time.Time) {
_ = m.Logger.Log(
"method", "sum",
"a", a,
"b", b,
"v", v,
"took", time.Since(begin),
)
}(time.Now())
v = m.AddService.Sum(a, b)
return
}
func (m loggingMiddleware) Concat(a, b string) (v string) {
defer func(begin time.Time) {
_ = m.Logger.Log(
"method", "concat",
"a", a,
"b", b,
"v", v,
"took", time.Since(begin),
)
}(time.Now())
v = m.AddService.Concat(a, b)
return
}
type instrumentingMiddleware struct {
server.AddService
requestDuration metrics.TimeHistogram
}
func (m instrumentingMiddleware) Sum(a, b int) (v int) {
defer func(begin time.Time) {
methodField := metrics.Field{Key: "method", Value: "sum"}
m.requestDuration.With(methodField).Observe(time.Since(begin))
}(time.Now())
v = m.AddService.Sum(a, b)
return
}
func (m instrumentingMiddleware) Concat(a, b string) (v string) {
defer func(begin time.Time) {
methodField := metrics.Field{Key: "method", Value: "concat"}
m.requestDuration.With(methodField).Observe(time.Since(begin))
}(time.Now())
v = m.AddService.Concat(a, b)
return
}