mirror of https://github.com/docker/cli.git
65 lines
2.6 KiB
Go
65 lines
2.6 KiB
Go
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package opentracing
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import "github.com/opentracing/opentracing-go/log"
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// A NoopTracer is a trivial, minimum overhead implementation of Tracer
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// for which all operations are no-ops.
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//
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// The primary use of this implementation is in libraries, such as RPC
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// frameworks, that make tracing an optional feature controlled by the
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// end user. A no-op implementation allows said libraries to use it
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// as the default Tracer and to write instrumentation that does
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// not need to keep checking if the tracer instance is nil.
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//
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// For the same reason, the NoopTracer is the default "global" tracer
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// (see GlobalTracer and SetGlobalTracer functions).
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//
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// WARNING: NoopTracer does not support baggage propagation.
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type NoopTracer struct{}
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type noopSpan struct{}
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type noopSpanContext struct{}
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var (
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defaultNoopSpanContext = noopSpanContext{}
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defaultNoopSpan = noopSpan{}
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defaultNoopTracer = NoopTracer{}
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)
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const (
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emptyString = ""
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)
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// noopSpanContext:
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func (n noopSpanContext) ForeachBaggageItem(handler func(k, v string) bool) {}
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// noopSpan:
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func (n noopSpan) Context() SpanContext { return defaultNoopSpanContext }
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func (n noopSpan) SetBaggageItem(key, val string) Span { return defaultNoopSpan }
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func (n noopSpan) BaggageItem(key string) string { return emptyString }
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func (n noopSpan) SetTag(key string, value interface{}) Span { return n }
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func (n noopSpan) LogFields(fields ...log.Field) {}
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func (n noopSpan) LogKV(keyVals ...interface{}) {}
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func (n noopSpan) Finish() {}
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func (n noopSpan) FinishWithOptions(opts FinishOptions) {}
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func (n noopSpan) SetOperationName(operationName string) Span { return n }
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func (n noopSpan) Tracer() Tracer { return defaultNoopTracer }
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func (n noopSpan) LogEvent(event string) {}
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func (n noopSpan) LogEventWithPayload(event string, payload interface{}) {}
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func (n noopSpan) Log(data LogData) {}
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// StartSpan belongs to the Tracer interface.
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func (n NoopTracer) StartSpan(operationName string, opts ...StartSpanOption) Span {
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return defaultNoopSpan
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}
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// Inject belongs to the Tracer interface.
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func (n NoopTracer) Inject(sp SpanContext, format interface{}, carrier interface{}) error {
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return nil
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}
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// Extract belongs to the Tracer interface.
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func (n NoopTracer) Extract(format interface{}, carrier interface{}) (SpanContext, error) {
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return nil, ErrSpanContextNotFound
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}
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