vendor/github.com/go-kit/kit/examples/addsvc/pkg/addendpoint/middleware.go

   1 package addendpoint
   2
   3 import (
   4         "context"
   5         "fmt"
   6         "time"
   7
   8         "github.com/go-kit/kit/endpoint"
   9         "github.com/go-kit/kit/log"
  10         "github.com/go-kit/kit/metrics"
  11 )
  12
  13 // InstrumentingMiddleware returns an endpoint middleware that records
  14 // the duration of each invocation to the passed histogram. The middleware adds
  15 // a single field: "success", which is "true" if no error is returned, and
  16 // "false" otherwise.
  17 func InstrumentingMiddleware(duration metrics.Histogram) endpoint.Middleware {
  18         return func(next endpoint.Endpoint) endpoint.Endpoint {
  19                 return func(ctx context.Context, request interface{}) (response interface{}, err error) {
  20
  21                         defer func(begin time.Time) {
  22                                 duration.With("success", fmt.Sprint(err == nil)).Observe(time.Since(begin).Seconds())
  23                         }(time.Now())
  24                         return next(ctx, request)
  25
  26                 }
  27         }
  28 }
  29
  30 // LoggingMiddleware returns an endpoint middleware that logs the
  31 // duration of each invocation, and the resulting error, if any.
  32 func LoggingMiddleware(logger log.Logger) endpoint.Middleware {
  33         return func(next endpoint.Endpoint) endpoint.Endpoint {
  34                 return func(ctx context.Context, request interface{}) (response interface{}, err error) {
  35
  36                         defer func(begin time.Time) {
  37                                 logger.Log("transport_error", err, "took", time.Since(begin))
  38                         }(time.Now())
  39                         return next(ctx, request)
  40
  41                 }
  42         }
  43 }