1 // Copyright The 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 15 // Package noop provides an implementation of the OpenTelemetry trace API that 16 // produces no telemetry and minimizes used computation resources. 17 // 18 // Using this package to implement the OpenTelemetry trace API will effectively 19 // disable OpenTelemetry. 20 // 21 // This implementation can be embedded in other implementations of the 22 // OpenTelemetry trace API. Doing so will mean the implementation defaults to 23 // no operation for methods it does not implement. 24 package noop // import "go.opentelemetry.io/otel/trace/noop" 25 26 import ( 27 "context" 28 29 "go.opentelemetry.io/otel/attribute" 30 "go.opentelemetry.io/otel/codes" 31 "go.opentelemetry.io/otel/trace" 32 "go.opentelemetry.io/otel/trace/embedded" 33 ) 34 35 var ( 36 // Compile-time check this implements the OpenTelemetry API. 37 38 _ trace.TracerProvider = TracerProvider{} 39 _ trace.Tracer = Tracer{} 40 _ trace.Span = Span{} 41 ) 42 43 // TracerProvider is an OpenTelemetry No-Op TracerProvider. 44 type TracerProvider struct{ embedded.TracerProvider } 45 46 // NewTracerProvider returns a TracerProvider that does not record any telemetry. 47 func NewTracerProvider() TracerProvider { 48 return TracerProvider{} 49 } 50 51 // Tracer returns an OpenTelemetry Tracer that does not record any telemetry. 52 func (TracerProvider) Tracer(string, ...trace.TracerOption) trace.Tracer { 53 return Tracer{} 54 } 55 56 // Tracer is an OpenTelemetry No-Op Tracer. 57 type Tracer struct{ embedded.Tracer } 58 59 // Start creates a span. The created span will be set in a child context of ctx 60 // and returned with the span. 61 // 62 // If ctx contains a span context, the returned span will also contain that 63 // span context. If the span context in ctx is for a non-recording span, that 64 // span instance will be returned directly. 65 func (t Tracer) Start(ctx context.Context, _ string, _ ...trace.SpanStartOption) (context.Context, trace.Span) { 66 span := trace.SpanFromContext(ctx) 67 68 // If the parent context contains a non-zero span context, that span 69 // context needs to be returned as a non-recording span 70 // (https://github.com/open-telemetry/opentelemetry-specification/blob/3a1dde966a4ce87cce5adf464359fe369741bbea/specification/trace/api.md#behavior-of-the-api-in-the-absence-of-an-installed-sdk). 71 var zeroSC trace.SpanContext 72 if sc := span.SpanContext(); !sc.Equal(zeroSC) { 73 if !span.IsRecording() { 74 // If the span is not recording return it directly. 75 return ctx, span 76 } 77 // Otherwise, return the span context needs in a non-recording span. 78 span = Span{sc: sc} 79 } else { 80 // No parent, return a No-Op span with an empty span context. 81 span = Span{} 82 } 83 return trace.ContextWithSpan(ctx, span), span 84 } 85 86 // Span is an OpenTelemetry No-Op Span. 87 type Span struct { 88 embedded.Span 89 90 sc trace.SpanContext 91 } 92 93 // SpanContext returns an empty span context. 94 func (s Span) SpanContext() trace.SpanContext { return s.sc } 95 96 // IsRecording always returns false. 97 func (Span) IsRecording() bool { return false } 98 99 // SetStatus does nothing. 100 func (Span) SetStatus(codes.Code, string) {} 101 102 // SetAttributes does nothing. 103 func (Span) SetAttributes(...attribute.KeyValue) {} 104 105 // End does nothing. 106 func (Span) End(...trace.SpanEndOption) {} 107 108 // RecordError does nothing. 109 func (Span) RecordError(error, ...trace.EventOption) {} 110 111 // AddEvent does nothing. 112 func (Span) AddEvent(string, ...trace.EventOption) {} 113 114 // SetName does nothing. 115 func (Span) SetName(string) {} 116 117 // TracerProvider returns a No-Op TracerProvider. 118 func (Span) TracerProvider() trace.TracerProvider { return TracerProvider{} } 119