| // 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 ( |
| "net/http" |
| |
| "go.opencensus.io/tag" |
| ) |
| |
| // WithRouteTag returns an http.Handler that records stats with the |
| // http_server_route tag set to the given value. |
| func WithRouteTag(handler http.Handler, route string) http.Handler { |
| return taggedHandlerFunc(func(w http.ResponseWriter, r *http.Request) []tag.Mutator { |
| addRoute := []tag.Mutator{tag.Upsert(KeyServerRoute, route)} |
| ctx, _ := tag.New(r.Context(), addRoute...) |
| r = r.WithContext(ctx) |
| handler.ServeHTTP(w, r) |
| return addRoute |
| }) |
| } |
| |
| // taggedHandlerFunc is a http.Handler that returns tags describing the |
| // processing of the request. These tags will be recorded along with the |
| // measures in this package at the end of the request. |
| type taggedHandlerFunc func(w http.ResponseWriter, r *http.Request) []tag.Mutator |
| |
| func (h taggedHandlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request) { |
| tags := h(w, r) |
| if a, ok := r.Context().Value(addedTagsKey{}).(*addedTags); ok { |
| a.t = append(a.t, tags...) |
| } |
| } |
| |
| type addedTagsKey struct{} |
| |
| type addedTags struct { |
| t []tag.Mutator |
| } |