100 lines
2.1 KiB
Go
100 lines
2.1 KiB
Go
// Package trace provides an interface for distributed tracing
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package trace
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import (
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"context"
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"time"
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"github.com/micro/go-micro/v2/metadata"
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)
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// Tracer is an interface for distributed tracing
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type Tracer interface {
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// Start a trace
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Start(ctx context.Context, name string) (context.Context, *Span)
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// Finish the trace
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Finish(*Span) error
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// Read the traces
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Read(...ReadOption) ([]*Span, error)
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}
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// SpanType describe the nature of the trace span
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type SpanType int
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const (
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// SpanTypeRequestInbound is a span created when serving a request
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SpanTypeRequestInbound SpanType = iota
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// SpanTypeRequestOutbound is a span created when making a service call
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SpanTypeRequestOutbound
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)
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// Span is used to record an entry
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type Span struct {
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// Id of the trace
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Trace string
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// name of the span
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Name string
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// id of the span
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Id string
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// parent span id
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Parent string
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// Start time
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Started time.Time
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// Duration in nano seconds
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Duration time.Duration
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// associated data
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Metadata map[string]string
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// Type
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Type SpanType
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}
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const (
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traceIDKey = "Micro-Trace-Id"
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spanIDKey = "Micro-Span-Id"
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)
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// FromContext returns a span from context
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func FromContext(ctx context.Context) (traceID string, parentSpanID string, isFound bool) {
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traceID, traceOk := metadata.Get(ctx, traceIDKey)
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microID, microOk := metadata.Get(ctx, "Micro-Id")
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if !traceOk && !microOk {
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isFound = false
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return
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}
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if !traceOk {
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traceID = microID
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}
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parentSpanID, ok := metadata.Get(ctx, spanIDKey)
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return traceID, parentSpanID, ok
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}
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// ToContext saves the trace and span ids in the context
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func ToContext(ctx context.Context, traceID, parentSpanID string) context.Context {
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return metadata.MergeContext(ctx, map[string]string{
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traceIDKey: traceID,
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spanIDKey: parentSpanID,
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}, true)
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}
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var (
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DefaultTracer Tracer = new(noop)
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)
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type noop struct{}
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func (n *noop) Init(...Option) error {
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return nil
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}
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func (n *noop) Start(ctx context.Context, name string) (context.Context, *Span) {
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return nil, nil
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}
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func (n *noop) Finish(*Span) error {
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return nil
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}
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func (n *noop) Read(...ReadOption) ([]*Span, error) {
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return nil, nil
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}
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