micro/debug/trace/trace.go
2020-01-24 21:44:48 +00:00

54 lines
1.1 KiB
Go

// Package trace provides an interface for distributed tracing
package trace
import (
"context"
"time"
)
// Trace is an interface for distributed tracing
type Trace interface {
// Start a trace
Start(ctx context.Context, name string) (context.Context, *Span)
// Finish the trace
Finish(*Span) error
// Read the traces
Read(...ReadOption) ([]*Span, error)
}
// Span is used to record an entry
type Span struct {
// Id of the trace
Trace string
// name of the span
Name string
// id of the span
Id string
// parent span id
Parent string
// Start time
Started time.Time
// Duration in nano seconds
Duration time.Duration
// associated data
Metadata map[string]string
}
type spanKey struct{}
var (
// Default tracer
DefaultTrace = NewTrace()
)
// FromContext returns a span from context
func FromContext(ctx context.Context) (*Span, bool) {
s, ok := ctx.Value(spanKey{}).(*Span)
return s, ok
}
// NewContext creates a new context with the span
func NewContext(ctx context.Context, s *Span) context.Context {
return context.WithValue(ctx, spanKey{}, s)
}