Import of https://github.com/ciena/voltctl at commit 40d61fbf3f910ed4017cf67c9c79e8e1f82a33a5
Change-Id: I8464c59e60d76cb8612891db3303878975b5416c
diff --git a/vendor/golang.org/x/net/trace/events.go b/vendor/golang.org/x/net/trace/events.go
new file mode 100644
index 0000000..c646a69
--- /dev/null
+++ b/vendor/golang.org/x/net/trace/events.go
@@ -0,0 +1,532 @@
+// Copyright 2015 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 trace
+
+import (
+ "bytes"
+ "fmt"
+ "html/template"
+ "io"
+ "log"
+ "net/http"
+ "runtime"
+ "sort"
+ "strconv"
+ "strings"
+ "sync"
+ "sync/atomic"
+ "text/tabwriter"
+ "time"
+)
+
+const maxEventsPerLog = 100
+
+type bucket struct {
+ MaxErrAge time.Duration
+ String string
+}
+
+var buckets = []bucket{
+ {0, "total"},
+ {10 * time.Second, "errs<10s"},
+ {1 * time.Minute, "errs<1m"},
+ {10 * time.Minute, "errs<10m"},
+ {1 * time.Hour, "errs<1h"},
+ {10 * time.Hour, "errs<10h"},
+ {24000 * time.Hour, "errors"},
+}
+
+// RenderEvents renders the HTML page typically served at /debug/events.
+// It does not do any auth checking. The request may be nil.
+//
+// Most users will use the Events handler.
+func RenderEvents(w http.ResponseWriter, req *http.Request, sensitive bool) {
+ now := time.Now()
+ data := &struct {
+ Families []string // family names
+ Buckets []bucket
+ Counts [][]int // eventLog count per family/bucket
+
+ // Set when a bucket has been selected.
+ Family string
+ Bucket int
+ EventLogs eventLogs
+ Expanded bool
+ }{
+ Buckets: buckets,
+ }
+
+ data.Families = make([]string, 0, len(families))
+ famMu.RLock()
+ for name := range families {
+ data.Families = append(data.Families, name)
+ }
+ famMu.RUnlock()
+ sort.Strings(data.Families)
+
+ // Count the number of eventLogs in each family for each error age.
+ data.Counts = make([][]int, len(data.Families))
+ for i, name := range data.Families {
+ // TODO(sameer): move this loop under the family lock.
+ f := getEventFamily(name)
+ data.Counts[i] = make([]int, len(data.Buckets))
+ for j, b := range data.Buckets {
+ data.Counts[i][j] = f.Count(now, b.MaxErrAge)
+ }
+ }
+
+ if req != nil {
+ var ok bool
+ data.Family, data.Bucket, ok = parseEventsArgs(req)
+ if !ok {
+ // No-op
+ } else {
+ data.EventLogs = getEventFamily(data.Family).Copy(now, buckets[data.Bucket].MaxErrAge)
+ }
+ if data.EventLogs != nil {
+ defer data.EventLogs.Free()
+ sort.Sort(data.EventLogs)
+ }
+ if exp, err := strconv.ParseBool(req.FormValue("exp")); err == nil {
+ data.Expanded = exp
+ }
+ }
+
+ famMu.RLock()
+ defer famMu.RUnlock()
+ if err := eventsTmpl().Execute(w, data); err != nil {
+ log.Printf("net/trace: Failed executing template: %v", err)
+ }
+}
+
+func parseEventsArgs(req *http.Request) (fam string, b int, ok bool) {
+ fam, bStr := req.FormValue("fam"), req.FormValue("b")
+ if fam == "" || bStr == "" {
+ return "", 0, false
+ }
+ b, err := strconv.Atoi(bStr)
+ if err != nil || b < 0 || b >= len(buckets) {
+ return "", 0, false
+ }
+ return fam, b, true
+}
+
+// An EventLog provides a log of events associated with a specific object.
+type EventLog interface {
+ // Printf formats its arguments with fmt.Sprintf and adds the
+ // result to the event log.
+ Printf(format string, a ...interface{})
+
+ // Errorf is like Printf, but it marks this event as an error.
+ Errorf(format string, a ...interface{})
+
+ // Finish declares that this event log is complete.
+ // The event log should not be used after calling this method.
+ Finish()
+}
+
+// NewEventLog returns a new EventLog with the specified family name
+// and title.
+func NewEventLog(family, title string) EventLog {
+ el := newEventLog()
+ el.ref()
+ el.Family, el.Title = family, title
+ el.Start = time.Now()
+ el.events = make([]logEntry, 0, maxEventsPerLog)
+ el.stack = make([]uintptr, 32)
+ n := runtime.Callers(2, el.stack)
+ el.stack = el.stack[:n]
+
+ getEventFamily(family).add(el)
+ return el
+}
+
+func (el *eventLog) Finish() {
+ getEventFamily(el.Family).remove(el)
+ el.unref() // matches ref in New
+}
+
+var (
+ famMu sync.RWMutex
+ families = make(map[string]*eventFamily) // family name => family
+)
+
+func getEventFamily(fam string) *eventFamily {
+ famMu.Lock()
+ defer famMu.Unlock()
+ f := families[fam]
+ if f == nil {
+ f = &eventFamily{}
+ families[fam] = f
+ }
+ return f
+}
+
+type eventFamily struct {
+ mu sync.RWMutex
+ eventLogs eventLogs
+}
+
+func (f *eventFamily) add(el *eventLog) {
+ f.mu.Lock()
+ f.eventLogs = append(f.eventLogs, el)
+ f.mu.Unlock()
+}
+
+func (f *eventFamily) remove(el *eventLog) {
+ f.mu.Lock()
+ defer f.mu.Unlock()
+ for i, el0 := range f.eventLogs {
+ if el == el0 {
+ copy(f.eventLogs[i:], f.eventLogs[i+1:])
+ f.eventLogs = f.eventLogs[:len(f.eventLogs)-1]
+ return
+ }
+ }
+}
+
+func (f *eventFamily) Count(now time.Time, maxErrAge time.Duration) (n int) {
+ f.mu.RLock()
+ defer f.mu.RUnlock()
+ for _, el := range f.eventLogs {
+ if el.hasRecentError(now, maxErrAge) {
+ n++
+ }
+ }
+ return
+}
+
+func (f *eventFamily) Copy(now time.Time, maxErrAge time.Duration) (els eventLogs) {
+ f.mu.RLock()
+ defer f.mu.RUnlock()
+ els = make(eventLogs, 0, len(f.eventLogs))
+ for _, el := range f.eventLogs {
+ if el.hasRecentError(now, maxErrAge) {
+ el.ref()
+ els = append(els, el)
+ }
+ }
+ return
+}
+
+type eventLogs []*eventLog
+
+// Free calls unref on each element of the list.
+func (els eventLogs) Free() {
+ for _, el := range els {
+ el.unref()
+ }
+}
+
+// eventLogs may be sorted in reverse chronological order.
+func (els eventLogs) Len() int { return len(els) }
+func (els eventLogs) Less(i, j int) bool { return els[i].Start.After(els[j].Start) }
+func (els eventLogs) Swap(i, j int) { els[i], els[j] = els[j], els[i] }
+
+// A logEntry is a timestamped log entry in an event log.
+type logEntry struct {
+ When time.Time
+ Elapsed time.Duration // since previous event in log
+ NewDay bool // whether this event is on a different day to the previous event
+ What string
+ IsErr bool
+}
+
+// WhenString returns a string representation of the elapsed time of the event.
+// It will include the date if midnight was crossed.
+func (e logEntry) WhenString() string {
+ if e.NewDay {
+ return e.When.Format("2006/01/02 15:04:05.000000")
+ }
+ return e.When.Format("15:04:05.000000")
+}
+
+// An eventLog represents an active event log.
+type eventLog struct {
+ // Family is the top-level grouping of event logs to which this belongs.
+ Family string
+
+ // Title is the title of this event log.
+ Title string
+
+ // Timing information.
+ Start time.Time
+
+ // Call stack where this event log was created.
+ stack []uintptr
+
+ // Append-only sequence of events.
+ //
+ // TODO(sameer): change this to a ring buffer to avoid the array copy
+ // when we hit maxEventsPerLog.
+ mu sync.RWMutex
+ events []logEntry
+ LastErrorTime time.Time
+ discarded int
+
+ refs int32 // how many buckets this is in
+}
+
+func (el *eventLog) reset() {
+ // Clear all but the mutex. Mutexes may not be copied, even when unlocked.
+ el.Family = ""
+ el.Title = ""
+ el.Start = time.Time{}
+ el.stack = nil
+ el.events = nil
+ el.LastErrorTime = time.Time{}
+ el.discarded = 0
+ el.refs = 0
+}
+
+func (el *eventLog) hasRecentError(now time.Time, maxErrAge time.Duration) bool {
+ if maxErrAge == 0 {
+ return true
+ }
+ el.mu.RLock()
+ defer el.mu.RUnlock()
+ return now.Sub(el.LastErrorTime) < maxErrAge
+}
+
+// delta returns the elapsed time since the last event or the log start,
+// and whether it spans midnight.
+// L >= el.mu
+func (el *eventLog) delta(t time.Time) (time.Duration, bool) {
+ if len(el.events) == 0 {
+ return t.Sub(el.Start), false
+ }
+ prev := el.events[len(el.events)-1].When
+ return t.Sub(prev), prev.Day() != t.Day()
+
+}
+
+func (el *eventLog) Printf(format string, a ...interface{}) {
+ el.printf(false, format, a...)
+}
+
+func (el *eventLog) Errorf(format string, a ...interface{}) {
+ el.printf(true, format, a...)
+}
+
+func (el *eventLog) printf(isErr bool, format string, a ...interface{}) {
+ e := logEntry{When: time.Now(), IsErr: isErr, What: fmt.Sprintf(format, a...)}
+ el.mu.Lock()
+ e.Elapsed, e.NewDay = el.delta(e.When)
+ if len(el.events) < maxEventsPerLog {
+ el.events = append(el.events, e)
+ } else {
+ // Discard the oldest event.
+ if el.discarded == 0 {
+ // el.discarded starts at two to count for the event it
+ // is replacing, plus the next one that we are about to
+ // drop.
+ el.discarded = 2
+ } else {
+ el.discarded++
+ }
+ // TODO(sameer): if this causes allocations on a critical path,
+ // change eventLog.What to be a fmt.Stringer, as in trace.go.
+ el.events[0].What = fmt.Sprintf("(%d events discarded)", el.discarded)
+ // The timestamp of the discarded meta-event should be
+ // the time of the last event it is representing.
+ el.events[0].When = el.events[1].When
+ copy(el.events[1:], el.events[2:])
+ el.events[maxEventsPerLog-1] = e
+ }
+ if e.IsErr {
+ el.LastErrorTime = e.When
+ }
+ el.mu.Unlock()
+}
+
+func (el *eventLog) ref() {
+ atomic.AddInt32(&el.refs, 1)
+}
+
+func (el *eventLog) unref() {
+ if atomic.AddInt32(&el.refs, -1) == 0 {
+ freeEventLog(el)
+ }
+}
+
+func (el *eventLog) When() string {
+ return el.Start.Format("2006/01/02 15:04:05.000000")
+}
+
+func (el *eventLog) ElapsedTime() string {
+ elapsed := time.Since(el.Start)
+ return fmt.Sprintf("%.6f", elapsed.Seconds())
+}
+
+func (el *eventLog) Stack() string {
+ buf := new(bytes.Buffer)
+ tw := tabwriter.NewWriter(buf, 1, 8, 1, '\t', 0)
+ printStackRecord(tw, el.stack)
+ tw.Flush()
+ return buf.String()
+}
+
+// printStackRecord prints the function + source line information
+// for a single stack trace.
+// Adapted from runtime/pprof/pprof.go.
+func printStackRecord(w io.Writer, stk []uintptr) {
+ for _, pc := range stk {
+ f := runtime.FuncForPC(pc)
+ if f == nil {
+ continue
+ }
+ file, line := f.FileLine(pc)
+ name := f.Name()
+ // Hide runtime.goexit and any runtime functions at the beginning.
+ if strings.HasPrefix(name, "runtime.") {
+ continue
+ }
+ fmt.Fprintf(w, "# %s\t%s:%d\n", name, file, line)
+ }
+}
+
+func (el *eventLog) Events() []logEntry {
+ el.mu.RLock()
+ defer el.mu.RUnlock()
+ return el.events
+}
+
+// freeEventLogs is a freelist of *eventLog
+var freeEventLogs = make(chan *eventLog, 1000)
+
+// newEventLog returns a event log ready to use.
+func newEventLog() *eventLog {
+ select {
+ case el := <-freeEventLogs:
+ return el
+ default:
+ return new(eventLog)
+ }
+}
+
+// freeEventLog adds el to freeEventLogs if there's room.
+// This is non-blocking.
+func freeEventLog(el *eventLog) {
+ el.reset()
+ select {
+ case freeEventLogs <- el:
+ default:
+ }
+}
+
+var eventsTmplCache *template.Template
+var eventsTmplOnce sync.Once
+
+func eventsTmpl() *template.Template {
+ eventsTmplOnce.Do(func() {
+ eventsTmplCache = template.Must(template.New("events").Funcs(template.FuncMap{
+ "elapsed": elapsed,
+ "trimSpace": strings.TrimSpace,
+ }).Parse(eventsHTML))
+ })
+ return eventsTmplCache
+}
+
+const eventsHTML = `
+<html>
+ <head>
+ <title>events</title>
+ </head>
+ <style type="text/css">
+ body {
+ font-family: sans-serif;
+ }
+ table#req-status td.family {
+ padding-right: 2em;
+ }
+ table#req-status td.active {
+ padding-right: 1em;
+ }
+ table#req-status td.empty {
+ color: #aaa;
+ }
+ table#reqs {
+ margin-top: 1em;
+ }
+ table#reqs tr.first {
+ {{if $.Expanded}}font-weight: bold;{{end}}
+ }
+ table#reqs td {
+ font-family: monospace;
+ }
+ table#reqs td.when {
+ text-align: right;
+ white-space: nowrap;
+ }
+ table#reqs td.elapsed {
+ padding: 0 0.5em;
+ text-align: right;
+ white-space: pre;
+ width: 10em;
+ }
+ address {
+ font-size: smaller;
+ margin-top: 5em;
+ }
+ </style>
+ <body>
+
+<h1>/debug/events</h1>
+
+<table id="req-status">
+ {{range $i, $fam := .Families}}
+ <tr>
+ <td class="family">{{$fam}}</td>
+
+ {{range $j, $bucket := $.Buckets}}
+ {{$n := index $.Counts $i $j}}
+ <td class="{{if not $bucket.MaxErrAge}}active{{end}}{{if not $n}}empty{{end}}">
+ {{if $n}}<a href="?fam={{$fam}}&b={{$j}}{{if $.Expanded}}&exp=1{{end}}">{{end}}
+ [{{$n}} {{$bucket.String}}]
+ {{if $n}}</a>{{end}}
+ </td>
+ {{end}}
+
+ </tr>{{end}}
+</table>
+
+{{if $.EventLogs}}
+<hr />
+<h3>Family: {{$.Family}}</h3>
+
+{{if $.Expanded}}<a href="?fam={{$.Family}}&b={{$.Bucket}}">{{end}}
+[Summary]{{if $.Expanded}}</a>{{end}}
+
+{{if not $.Expanded}}<a href="?fam={{$.Family}}&b={{$.Bucket}}&exp=1">{{end}}
+[Expanded]{{if not $.Expanded}}</a>{{end}}
+
+<table id="reqs">
+ <tr><th>When</th><th>Elapsed</th></tr>
+ {{range $el := $.EventLogs}}
+ <tr class="first">
+ <td class="when">{{$el.When}}</td>
+ <td class="elapsed">{{$el.ElapsedTime}}</td>
+ <td>{{$el.Title}}
+ </tr>
+ {{if $.Expanded}}
+ <tr>
+ <td class="when"></td>
+ <td class="elapsed"></td>
+ <td><pre>{{$el.Stack|trimSpace}}</pre></td>
+ </tr>
+ {{range $el.Events}}
+ <tr>
+ <td class="when">{{.WhenString}}</td>
+ <td class="elapsed">{{elapsed .Elapsed}}</td>
+ <td>.{{if .IsErr}}E{{else}}.{{end}}. {{.What}}</td>
+ </tr>
+ {{end}}
+ {{end}}
+ {{end}}
+</table>
+{{end}}
+ </body>
+</html>
+`