1// Copyright 2019 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5// Package core provides support for event based telemetry. 6package core 7 8import ( 9 "fmt" 10 "time" 11 12 "golang.org/x/tools/internal/event/label" 13) 14 15// Event holds the information about an event of note that occurred. 16type Event struct { 17 at time.Time 18 19 // As events are often on the stack, storing the first few labels directly 20 // in the event can avoid an allocation at all for the very common cases of 21 // simple events. 22 // The length needs to be large enough to cope with the majority of events 23 // but no so large as to cause undue stack pressure. 24 // A log message with two values will use 3 labels (one for each value and 25 // one for the message itself). 26 27 static [3]label.Label // inline storage for the first few labels 28 dynamic []label.Label // dynamically sized storage for remaining labels 29} 30 31// eventLabelMap implements label.Map for a the labels of an Event. 32type eventLabelMap struct { 33 event Event 34} 35 36func (ev Event) At() time.Time { return ev.at } 37 38func (ev Event) Format(f fmt.State, r rune) { 39 if !ev.at.IsZero() { 40 fmt.Fprint(f, ev.at.Format("2006/01/02 15:04:05 ")) 41 } 42 for index := 0; ev.Valid(index); index++ { 43 if l := ev.Label(index); l.Valid() { 44 fmt.Fprintf(f, "\n\t%v", l) 45 } 46 } 47} 48 49func (ev Event) Valid(index int) bool { 50 return index >= 0 && index < len(ev.static)+len(ev.dynamic) 51} 52 53func (ev Event) Label(index int) label.Label { 54 if index < len(ev.static) { 55 return ev.static[index] 56 } 57 return ev.dynamic[index-len(ev.static)] 58} 59 60func (ev Event) Find(key label.Key) label.Label { 61 for _, l := range ev.static { 62 if l.Key() == key { 63 return l 64 } 65 } 66 for _, l := range ev.dynamic { 67 if l.Key() == key { 68 return l 69 } 70 } 71 return label.Label{} 72} 73 74func MakeEvent(static [3]label.Label, labels []label.Label) Event { 75 return Event{ 76 static: static, 77 dynamic: labels, 78 } 79} 80 81// CloneEvent event returns a copy of the event with the time adjusted to at. 82func CloneEvent(ev Event, at time.Time) Event { 83 ev.at = at 84 return ev 85} 86