mirror of
https://github.com/golang/go
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a90b7300be
Instead of tagging events with their type, instead we infer the type from the label pattern. The standard event creators all have a matching test that returns true if the the labels pattern matches the ones that would be built by the creator. Spans and logs already have a unique label pattern, other event types required a special label marker. This makes the system much more extensible, and also cleans up some the API. Change-Id: I1fbc9ec07aa84ead6c12bbd5ca65b13b605bfa4a Reviewed-on: https://go-review.googlesource.com/c/tools/+/229242 Run-TryBot: Ian Cottrell <iancottrell@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
118 lines
2.6 KiB
Go
118 lines
2.6 KiB
Go
// Copyright 2019 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package export
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import (
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"context"
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"fmt"
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"sync"
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"golang.org/x/tools/internal/event"
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"golang.org/x/tools/internal/event/core"
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"golang.org/x/tools/internal/event/keys"
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"golang.org/x/tools/internal/event/label"
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)
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type SpanContext struct {
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TraceID TraceID
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SpanID SpanID
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}
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type Span struct {
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Name string
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ID SpanContext
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ParentID SpanID
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mu sync.Mutex
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start core.Event
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finish core.Event
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events []core.Event
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}
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type contextKeyType int
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const (
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spanContextKey = contextKeyType(iota)
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labelContextKey
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)
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func GetSpan(ctx context.Context) *Span {
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v := ctx.Value(spanContextKey)
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if v == nil {
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return nil
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}
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return v.(*Span)
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}
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// Spans creates an exporter that maintains hierarchical span structure in the
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// context.
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// It creates new spans on start events, adds events to the current span on
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// log or label, and closes the span on end events.
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// The span structure can then be used by other exporters.
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func Spans(output event.Exporter) event.Exporter {
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return func(ctx context.Context, ev core.Event, lm label.Map) context.Context {
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switch {
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case event.IsLog(ev), event.IsLabel(ev):
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if span := GetSpan(ctx); span != nil {
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span.mu.Lock()
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span.events = append(span.events, ev)
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span.mu.Unlock()
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}
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case event.IsStart(ev):
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span := &Span{
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Name: keys.Start.Get(lm),
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start: ev,
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}
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if parent := GetSpan(ctx); parent != nil {
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span.ID.TraceID = parent.ID.TraceID
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span.ParentID = parent.ID.SpanID
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} else {
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span.ID.TraceID = newTraceID()
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}
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span.ID.SpanID = newSpanID()
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ctx = context.WithValue(ctx, spanContextKey, span)
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case event.IsEnd(ev):
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if span := GetSpan(ctx); span != nil {
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span.mu.Lock()
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span.finish = ev
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span.mu.Unlock()
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}
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case event.IsDetach(ev):
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ctx = context.WithValue(ctx, spanContextKey, nil)
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}
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return output(ctx, ev, lm)
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}
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}
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func (s *SpanContext) Format(f fmt.State, r rune) {
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fmt.Fprintf(f, "%v:%v", s.TraceID, s.SpanID)
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}
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func (s *Span) Start() core.Event {
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// start never changes after construction, so we dont need to hold the mutex
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return s.start
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}
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func (s *Span) Finish() core.Event {
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s.mu.Lock()
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defer s.mu.Unlock()
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return s.finish
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}
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func (s *Span) Events() []core.Event {
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s.mu.Lock()
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defer s.mu.Unlock()
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return s.events
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}
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func (s *Span) Format(f fmt.State, r rune) {
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s.mu.Lock()
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defer s.mu.Unlock()
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fmt.Fprintf(f, "%v %v", s.Name, s.ID)
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if s.ParentID.IsValid() {
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fmt.Fprintf(f, "[%v]", s.ParentID)
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}
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fmt.Fprintf(f, " %v->%v", s.start, s.finish)
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}
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