cmd/bpa-operator/vendor/go.opencensus.io/plugin/ochttp/client_stats.go

   1 // Copyright 2018, OpenCensus Authors
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 //     http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15 package ochttp
  16
  17 import (
  18         "context"
  19         "io"
  20         "net/http"
  21         "strconv"
  22         "sync"
  23         "time"
  24
  25         "go.opencensus.io/stats"
  26         "go.opencensus.io/tag"
  27 )
  28
  29 // statsTransport is an http.RoundTripper that collects stats for the outgoing requests.
  30 type statsTransport struct {
  31         base http.RoundTripper
  32 }
  33
  34 // RoundTrip implements http.RoundTripper, delegating to Base and recording stats for the request.
  35 func (t statsTransport) RoundTrip(req *http.Request) (*http.Response, error) {
  36         ctx, _ := tag.New(req.Context(),
  37                 tag.Upsert(KeyClientHost, req.Host),
  38                 tag.Upsert(Host, req.Host),
  39                 tag.Upsert(KeyClientPath, req.URL.Path),
  40                 tag.Upsert(Path, req.URL.Path),
  41                 tag.Upsert(KeyClientMethod, req.Method),
  42                 tag.Upsert(Method, req.Method))
  43         req = req.WithContext(ctx)
  44         track := &tracker{
  45                 start: time.Now(),
  46                 ctx:   ctx,
  47         }
  48         if req.Body == nil {
  49                 // TODO: Handle cases where ContentLength is not set.
  50                 track.reqSize = -1
  51         } else if req.ContentLength > 0 {
  52                 track.reqSize = req.ContentLength
  53         }
  54         stats.Record(ctx, ClientRequestCount.M(1))
  55
  56         // Perform request.
  57         resp, err := t.base.RoundTrip(req)
  58
  59         if err != nil {
  60                 track.statusCode = http.StatusInternalServerError
  61                 track.end()
  62         } else {
  63                 track.statusCode = resp.StatusCode
  64                 if req.Method != "HEAD" {
  65                         track.respContentLength = resp.ContentLength
  66                 }
  67                 if resp.Body == nil {
  68                         track.end()
  69                 } else {
  70                         track.body = resp.Body
  71                         resp.Body = wrappedBody(track, resp.Body)
  72                 }
  73         }
  74         return resp, err
  75 }
  76
  77 // CancelRequest cancels an in-flight request by closing its connection.
  78 func (t statsTransport) CancelRequest(req *http.Request) {
  79         type canceler interface {
  80                 CancelRequest(*http.Request)
  81         }
  82         if cr, ok := t.base.(canceler); ok {
  83                 cr.CancelRequest(req)
  84         }
  85 }
  86
  87 type tracker struct {
  88         ctx               context.Context
  89         respSize          int64
  90         respContentLength int64
  91         reqSize           int64
  92         start             time.Time
  93         body              io.ReadCloser
  94         statusCode        int
  95         endOnce           sync.Once
  96 }
  97
  98 var _ io.ReadCloser = (*tracker)(nil)
  99
 100 func (t *tracker) end() {
 101         t.endOnce.Do(func() {
 102                 latencyMs := float64(time.Since(t.start)) / float64(time.Millisecond)
 103                 respSize := t.respSize
 104                 if t.respSize == 0 && t.respContentLength > 0 {
 105                         respSize = t.respContentLength
 106                 }
 107                 m := []stats.Measurement{
 108                         ClientSentBytes.M(t.reqSize),
 109                         ClientReceivedBytes.M(respSize),
 110                         ClientRoundtripLatency.M(latencyMs),
 111                         ClientLatency.M(latencyMs),
 112                         ClientResponseBytes.M(t.respSize),
 113                 }
 114                 if t.reqSize >= 0 {
 115                         m = append(m, ClientRequestBytes.M(t.reqSize))
 116                 }
 117
 118                 stats.RecordWithTags(t.ctx, []tag.Mutator{
 119                         tag.Upsert(StatusCode, strconv.Itoa(t.statusCode)),
 120                         tag.Upsert(KeyClientStatus, strconv.Itoa(t.statusCode)),
 121                 }, m...)
 122         })
 123 }
 124
 125 func (t *tracker) Read(b []byte) (int, error) {
 126         n, err := t.body.Read(b)
 127         t.respSize += int64(n)
 128         switch err {
 129         case nil:
 130                 return n, nil
 131         case io.EOF:
 132                 t.end()
 133         }
 134         return n, err
 135 }
 136
 137 func (t *tracker) Close() error {
 138         // Invoking endSpan on Close will help catch the cases
 139         // in which a read returned a non-nil error, we set the
 140         // span status but didn't end the span.
 141         t.end()
 142         return t.body.Close()
 143 }