68 lines
1.5 KiB
Go
68 lines
1.5 KiB
Go
// Package tracer provides an interface for distributed tracing
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package tracer
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import (
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"context"
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)
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type tracerKey struct{}
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// FromContext returns a tracer from context
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func FromContext(ctx context.Context) (Tracer, bool) {
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if ctx == nil {
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return nil, false
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}
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if tracer, ok := ctx.Value(tracerKey{}).(Tracer); ok {
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return tracer, true
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}
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return nil, false
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}
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// MustContext returns a tracer from context
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func MustContext(ctx context.Context) Tracer {
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t, ok := FromContext(ctx)
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if !ok {
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panic("missing tracer")
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}
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return t
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}
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// NewContext saves the tracer in the context
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func NewContext(ctx context.Context, tracer Tracer) context.Context {
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if ctx == nil {
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ctx = context.Background()
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}
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return context.WithValue(ctx, tracerKey{}, tracer)
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}
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type spanKey struct{}
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// SpanFromContext returns a span from context
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func SpanFromContext(ctx context.Context) (Span, bool) {
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if ctx == nil {
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return nil, false
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}
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if span, ok := ctx.Value(spanKey{}).(Span); ok {
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return span, true
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}
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return nil, false
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}
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// NewSpanContext saves the span in the context
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func NewSpanContext(ctx context.Context, span Span) context.Context {
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if ctx == nil {
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ctx = context.Background()
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}
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return context.WithValue(ctx, spanKey{}, span)
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}
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// SetOption returns a function to setup a context with given value
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func SetOption(k, v interface{}) Option {
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return func(o *Options) {
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if o.Context == nil {
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o.Context = context.Background()
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}
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o.Context = context.WithValue(o.Context, k, v)
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}
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}
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