github.com/matrixorigin/matrixone@v1.2.0/pkg/util/trace/noop_trace.go (about) 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 // Portions of this file are additionally subject to the following 16 // copyright. 17 // 18 // Copyright (C) 2022 Matrix Origin. 19 // 20 // Modified the behavior and the interface of the step. 21 22 package trace 23 24 import ( 25 "context" 26 "go.uber.org/zap" 27 ) 28 29 var _ TracerProvider = &noopTracerProvider{} 30 var _ Tracer = &NoopTracer{} 31 var _ Span = &NoopSpan{} 32 33 type noopTracerProvider struct{} 34 35 func (n noopTracerProvider) Tracer(string, ...TracerOption) Tracer { 36 return NoopTracer{} 37 } 38 39 // NoopTracer is an implementation of Tracer that preforms no operations. 40 type NoopTracer struct{} 41 42 // Start carries forward a non-recording Span, if one is present in the context, otherwise it 43 // creates a no-op Span. 44 func (t NoopTracer) Start(ctx context.Context, name string, opts ...SpanStartOption) (context.Context, Span) { 45 span := SpanFromContext(ctx) 46 if _, ok := span.(NoopSpan); !ok { 47 // span is likely already a NoopSpan, but let's be sure 48 span = NoopSpan{} 49 return ContextWithSpan(ctx, span), span 50 } else if len(opts) > 0 { 51 var sc = SpanConfig{} 52 for _, opt := range opts { 53 opt.ApplySpanStart(&sc) 54 } 55 if sc.NewRoot { 56 span = NoopSpan{} 57 return ContextWithSpan(ctx, span), span 58 } 59 } 60 return ctx, span 61 } 62 63 func (t NoopTracer) Debug(ctx context.Context, name string, opts ...SpanStartOption) (context.Context, Span) { 64 return t.Start(ctx, name, opts...) 65 } 66 67 func (t NoopTracer) IsEnable(opts ...SpanStartOption) bool { return false } 68 69 // NoopSpan is an implementation of Span that preforms no operations. 70 type NoopSpan struct{} 71 72 var _ Span = NoopSpan{} 73 74 // SpanContext returns an empty span context. 75 func (NoopSpan) SpanContext() SpanContext { return SpanContext{} } 76 77 func (NoopSpan) ParentSpanContext() SpanContext { return SpanContext{} } 78 79 // End does nothing. 80 func (NoopSpan) End(...SpanEndOption) {} 81 82 func (NoopSpan) AddExtraFields(...zap.Field) {} 83 84 // SetName does nothing. 85 func (NoopSpan) SetName(string) {} 86 87 // TracerProvider returns a no-op TracerProvider. 88 func (NoopSpan) TracerProvider() TracerProvider { return noopTracerProvider{} } 89 90 // NonRecordingSpan keep SpanContext{TraceID, SpanID} 91 type NonRecordingSpan struct { 92 NoopSpan 93 sc SpanContext 94 } 95 96 func (s *NonRecordingSpan) SpanContext() SpanContext { return s.sc } 97 func (s *NonRecordingSpan) ParentSpanContext() SpanContext { return SpanContext{} }