1// Copyright 2017, 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 16package ocgrpc 17 18import ( 19 "time" 20 21 "golang.org/x/net/context" 22 23 "go.opencensus.io/tag" 24 "google.golang.org/grpc/grpclog" 25 "google.golang.org/grpc/stats" 26) 27 28// statsTagRPC gets the metadata from gRPC context, extracts the encoded tags from 29// it and creates a new tag.Map and puts them into the returned context. 30func (h *ServerHandler) statsTagRPC(ctx context.Context, info *stats.RPCTagInfo) context.Context { 31 startTime := time.Now() 32 if info == nil { 33 if grpclog.V(2) { 34 grpclog.Infof("opencensus: TagRPC called with nil info.") 35 } 36 return ctx 37 } 38 d := &rpcData{ 39 startTime: startTime, 40 method: info.FullMethodName, 41 } 42 propagated := h.extractPropagatedTags(ctx) 43 ctx = tag.NewContext(ctx, propagated) 44 ctx, _ = tag.New(ctx, tag.Upsert(KeyServerMethod, methodName(info.FullMethodName))) 45 return context.WithValue(ctx, rpcDataKey, d) 46} 47 48// extractPropagatedTags creates a new tag map containing the tags extracted from the 49// gRPC metadata. 50func (h *ServerHandler) extractPropagatedTags(ctx context.Context) *tag.Map { 51 buf := stats.Tags(ctx) 52 if buf == nil { 53 return nil 54 } 55 propagated, err := tag.Decode(buf) 56 if err != nil { 57 if grpclog.V(2) { 58 grpclog.Warningf("opencensus: Failed to decode tags from gRPC metadata failed to decode: %v", err) 59 } 60 return nil 61 } 62 return propagated 63} 64