| // Copyright 2019 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package export |
| |
| import ( |
| "context" |
| "fmt" |
| "time" |
| |
| "golang.org/x/tools/internal/telemetry/event" |
| ) |
| |
| type SpanContext struct { |
| TraceID TraceID |
| SpanID SpanID |
| } |
| |
| type Span struct { |
| Name string |
| ID SpanContext |
| ParentID SpanID |
| Start time.Time |
| Finish time.Time |
| Tags event.TagSet |
| Events []event.Event |
| } |
| |
| type contextKeyType int |
| |
| const ( |
| spanContextKey = contextKeyType(iota) |
| ) |
| |
| func GetSpan(ctx context.Context) *Span { |
| v := ctx.Value(spanContextKey) |
| if v == nil { |
| return nil |
| } |
| return v.(*Span) |
| } |
| |
| // ContextSpan is an exporter that maintains hierarchical span structure in the |
| // context. |
| // It creates new spans on EventStartSpan, adds events to the current span on |
| // EventLog or EventTag, and closes the span on EventEndSpan. |
| // The span structure can then be used by other exporters. |
| func ContextSpan(ctx context.Context, ev event.Event) (context.Context, event.Event) { |
| switch { |
| case ev.IsLog(), ev.IsLabel(): |
| if span := GetSpan(ctx); span != nil { |
| span.Events = append(span.Events, ev) |
| } |
| case ev.IsStartSpan(): |
| span := &Span{ |
| Name: ev.Message, |
| Start: ev.At, |
| Tags: ev.Tags, |
| } |
| if parent := GetSpan(ctx); parent != nil { |
| span.ID.TraceID = parent.ID.TraceID |
| span.ParentID = parent.ID.SpanID |
| } else { |
| span.ID.TraceID = newTraceID() |
| } |
| span.ID.SpanID = newSpanID() |
| ctx = context.WithValue(ctx, spanContextKey, span) |
| case ev.IsEndSpan(): |
| if span := GetSpan(ctx); span != nil { |
| span.Finish = ev.At |
| } |
| case ev.IsDetach(): |
| return context.WithValue(ctx, spanContextKey, nil), ev |
| } |
| return ctx, ev |
| } |
| |
| func (s *SpanContext) Format(f fmt.State, r rune) { |
| fmt.Fprintf(f, "%v:%v", s.TraceID, s.SpanID) |
| } |
| |
| func (s *Span) Format(f fmt.State, r rune) { |
| fmt.Fprintf(f, "%v %v", s.Name, s.ID) |
| if s.ParentID.IsValid() { |
| fmt.Fprintf(f, "[%v]", s.ParentID) |
| } |
| fmt.Fprintf(f, " %v->%v", s.Start, s.Finish) |
| } |