1// Copyright 2019, OpenTelemetry 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 15package stdout 16 17import ( 18 "context" 19 "encoding/json" 20 "io" 21 "os" 22 23 export "go.opentelemetry.io/otel/sdk/export/trace" 24) 25 26// Options are the options to be used when initializing a stdout export. 27type Options struct { 28 // Writer is the destination. If not set, os.Stdout is used. 29 Writer io.Writer 30 31 // PrettyPrint will pretty the json representation of the span, 32 // making it print "pretty". Default is false. 33 PrettyPrint bool 34} 35 36// Exporter is an implementation of trace.Exporter that writes spans to stdout. 37type Exporter struct { 38 pretty bool 39 outputWriter io.Writer 40} 41 42func NewExporter(o Options) (*Exporter, error) { 43 if o.Writer == nil { 44 o.Writer = os.Stdout 45 } 46 return &Exporter{ 47 pretty: o.PrettyPrint, 48 outputWriter: o.Writer, 49 }, nil 50} 51 52// ExportSpan writes a SpanData in json format to stdout. 53func (e *Exporter) ExportSpan(ctx context.Context, data *export.SpanData) { 54 var jsonSpan []byte 55 var err error 56 if e.pretty { 57 jsonSpan, err = json.MarshalIndent(data, "", "\t") 58 } else { 59 jsonSpan, err = json.Marshal(data) 60 } 61 if err != nil { 62 // ignore writer failures for now 63 _, _ = e.outputWriter.Write([]byte("Error converting spanData to json: " + err.Error())) 64 return 65 } 66 // ignore writer failures for now 67 _, _ = e.outputWriter.Write(append(jsonSpan, byte('\n'))) 68} 69