| // Copyright 2018, OpenCensus Authors |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package ochttp |
| |
| import ( |
| "context" |
| "io" |
| "net/http" |
| "strconv" |
| "sync" |
| "time" |
| |
| "go.opencensus.io/stats" |
| "go.opencensus.io/tag" |
| ) |
| |
| // statsTransport is an http.RoundTripper that collects stats for the outgoing requests. |
| type statsTransport struct { |
| base http.RoundTripper |
| } |
| |
| // RoundTrip implements http.RoundTripper, delegating to Base and recording stats for the request. |
| func (t statsTransport) RoundTrip(req *http.Request) (*http.Response, error) { |
| ctx, _ := tag.New(req.Context(), |
| tag.Upsert(KeyClientHost, req.Host), |
| tag.Upsert(Host, req.Host), |
| tag.Upsert(KeyClientPath, req.URL.Path), |
| tag.Upsert(Path, req.URL.Path), |
| tag.Upsert(KeyClientMethod, req.Method), |
| tag.Upsert(Method, req.Method)) |
| req = req.WithContext(ctx) |
| track := &tracker{ |
| start: time.Now(), |
| ctx: ctx, |
| } |
| if req.Body == nil { |
| // TODO: Handle cases where ContentLength is not set. |
| track.reqSize = -1 |
| } else if req.ContentLength > 0 { |
| track.reqSize = req.ContentLength |
| } |
| stats.Record(ctx, ClientRequestCount.M(1)) |
| |
| // Perform request. |
| resp, err := t.base.RoundTrip(req) |
| |
| if err != nil { |
| track.statusCode = http.StatusInternalServerError |
| track.end() |
| } else { |
| track.statusCode = resp.StatusCode |
| if req.Method != "HEAD" { |
| track.respContentLength = resp.ContentLength |
| } |
| if resp.Body == nil { |
| track.end() |
| } else { |
| track.body = resp.Body |
| resp.Body = wrappedBody(track, resp.Body) |
| } |
| } |
| return resp, err |
| } |
| |
| // CancelRequest cancels an in-flight request by closing its connection. |
| func (t statsTransport) CancelRequest(req *http.Request) { |
| type canceler interface { |
| CancelRequest(*http.Request) |
| } |
| if cr, ok := t.base.(canceler); ok { |
| cr.CancelRequest(req) |
| } |
| } |
| |
| type tracker struct { |
| ctx context.Context |
| respSize int64 |
| respContentLength int64 |
| reqSize int64 |
| start time.Time |
| body io.ReadCloser |
| statusCode int |
| endOnce sync.Once |
| } |
| |
| var _ io.ReadCloser = (*tracker)(nil) |
| |
| func (t *tracker) end() { |
| t.endOnce.Do(func() { |
| latencyMs := float64(time.Since(t.start)) / float64(time.Millisecond) |
| respSize := t.respSize |
| if t.respSize == 0 && t.respContentLength > 0 { |
| respSize = t.respContentLength |
| } |
| m := []stats.Measurement{ |
| ClientSentBytes.M(t.reqSize), |
| ClientReceivedBytes.M(respSize), |
| ClientRoundtripLatency.M(latencyMs), |
| ClientLatency.M(latencyMs), |
| ClientResponseBytes.M(t.respSize), |
| } |
| if t.reqSize >= 0 { |
| m = append(m, ClientRequestBytes.M(t.reqSize)) |
| } |
| |
| stats.RecordWithTags(t.ctx, []tag.Mutator{ |
| tag.Upsert(StatusCode, strconv.Itoa(t.statusCode)), |
| tag.Upsert(KeyClientStatus, strconv.Itoa(t.statusCode)), |
| }, m...) |
| }) |
| } |
| |
| func (t *tracker) Read(b []byte) (int, error) { |
| n, err := t.body.Read(b) |
| t.respSize += int64(n) |
| switch err { |
| case nil: |
| return n, nil |
| case io.EOF: |
| t.end() |
| } |
| return n, err |
| } |
| |
| func (t *tracker) Close() error { |
| // Invoking endSpan on Close will help catch the cases |
| // in which a read returned a non-nil error, we set the |
| // span status but didn't end the span. |
| t.end() |
| return t.body.Close() |
| } |