vendor files

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>
+`

vendor/golang.org/x/net/trace/histogram.go

@@ -0,0 +1,365 @@
+// 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
+
+// This file implements histogramming for RPC statistics collection.
+
+import (
+	"bytes"
+	"fmt"
+	"html/template"
+	"log"
+	"math"
+	"sync"
+
+	"golang.org/x/net/internal/timeseries"
+)
+
+const (
+	bucketCount = 38
+)
+
+// histogram keeps counts of values in buckets that are spaced
+// out in powers of 2: 0-1, 2-3, 4-7...
+// histogram implements timeseries.Observable
+type histogram struct {
+	sum          int64   // running total of measurements
+	sumOfSquares float64 // square of running total
+	buckets      []int64 // bucketed values for histogram
+	value        int     // holds a single value as an optimization
+	valueCount   int64   // number of values recorded for single value
+}
+
+// AddMeasurement records a value measurement observation to the histogram.
+func (h *histogram) addMeasurement(value int64) {
+	// TODO: assert invariant
+	h.sum += value
+	h.sumOfSquares += float64(value) * float64(value)
+
+	bucketIndex := getBucket(value)
+
+	if h.valueCount == 0 || (h.valueCount > 0 && h.value == bucketIndex) {
+		h.value = bucketIndex
+		h.valueCount++
+	} else {
+		h.allocateBuckets()
+		h.buckets[bucketIndex]++
+	}
+}
+
+func (h *histogram) allocateBuckets() {
+	if h.buckets == nil {
+		h.buckets = make([]int64, bucketCount)
+		h.buckets[h.value] = h.valueCount
+		h.value = 0
+		h.valueCount = -1
+	}
+}
+
+func log2(i int64) int {
+	n := 0
+	for ; i >= 0x100; i >>= 8 {
+		n += 8
+	}
+	for ; i > 0; i >>= 1 {
+		n += 1
+	}
+	return n
+}
+
+func getBucket(i int64) (index int) {
+	index = log2(i) - 1
+	if index < 0 {
+		index = 0
+	}
+	if index >= bucketCount {
+		index = bucketCount - 1
+	}
+	return
+}
+
+// Total returns the number of recorded observations.
+func (h *histogram) total() (total int64) {
+	if h.valueCount >= 0 {
+		total = h.valueCount
+	}
+	for _, val := range h.buckets {
+		total += int64(val)
+	}
+	return
+}
+
+// Average returns the average value of recorded observations.
+func (h *histogram) average() float64 {
+	t := h.total()
+	if t == 0 {
+		return 0
+	}
+	return float64(h.sum) / float64(t)
+}
+
+// Variance returns the variance of recorded observations.
+func (h *histogram) variance() float64 {
+	t := float64(h.total())
+	if t == 0 {
+		return 0
+	}
+	s := float64(h.sum) / t
+	return h.sumOfSquares/t - s*s
+}
+
+// StandardDeviation returns the standard deviation of recorded observations.
+func (h *histogram) standardDeviation() float64 {
+	return math.Sqrt(h.variance())
+}
+
+// PercentileBoundary estimates the value that the given fraction of recorded
+// observations are less than.
+func (h *histogram) percentileBoundary(percentile float64) int64 {
+	total := h.total()
+
+	// Corner cases (make sure result is strictly less than Total())
+	if total == 0 {
+		return 0
+	} else if total == 1 {
+		return int64(h.average())
+	}
+
+	percentOfTotal := round(float64(total) * percentile)
+	var runningTotal int64
+
+	for i := range h.buckets {
+		value := h.buckets[i]
+		runningTotal += value
+		if runningTotal == percentOfTotal {
+			// We hit an exact bucket boundary. If the next bucket has data, it is a
+			// good estimate of the value. If the bucket is empty, we interpolate the
+			// midpoint between the next bucket's boundary and the next non-zero
+			// bucket. If the remaining buckets are all empty, then we use the
+			// boundary for the next bucket as the estimate.
+			j := uint8(i + 1)
+			min := bucketBoundary(j)
+			if runningTotal < total {
+				for h.buckets[j] == 0 {
+					j++
+				}
+			}
+			max := bucketBoundary(j)
+			return min + round(float64(max-min)/2)
+		} else if runningTotal > percentOfTotal {
+			// The value is in this bucket. Interpolate the value.
+			delta := runningTotal - percentOfTotal
+			percentBucket := float64(value-delta) / float64(value)
+			bucketMin := bucketBoundary(uint8(i))
+			nextBucketMin := bucketBoundary(uint8(i + 1))
+			bucketSize := nextBucketMin - bucketMin
+			return bucketMin + round(percentBucket*float64(bucketSize))
+		}
+	}
+	return bucketBoundary(bucketCount - 1)
+}
+
+// Median returns the estimated median of the observed values.
+func (h *histogram) median() int64 {
+	return h.percentileBoundary(0.5)
+}
+
+// Add adds other to h.
+func (h *histogram) Add(other timeseries.Observable) {
+	o := other.(*histogram)
+	if o.valueCount == 0 {
+		// Other histogram is empty
+	} else if h.valueCount >= 0 && o.valueCount > 0 && h.value == o.value {
+		// Both have a single bucketed value, aggregate them
+		h.valueCount += o.valueCount
+	} else {
+		// Two different values necessitate buckets in this histogram
+		h.allocateBuckets()
+		if o.valueCount >= 0 {
+			h.buckets[o.value] += o.valueCount
+		} else {
+			for i := range h.buckets {
+				h.buckets[i] += o.buckets[i]
+			}
+		}
+	}
+	h.sumOfSquares += o.sumOfSquares
+	h.sum += o.sum
+}
+
+// Clear resets the histogram to an empty state, removing all observed values.
+func (h *histogram) Clear() {
+	h.buckets = nil
+	h.value = 0
+	h.valueCount = 0
+	h.sum = 0
+	h.sumOfSquares = 0
+}
+
+// CopyFrom copies from other, which must be a *histogram, into h.
+func (h *histogram) CopyFrom(other timeseries.Observable) {
+	o := other.(*histogram)
+	if o.valueCount == -1 {
+		h.allocateBuckets()
+		copy(h.buckets, o.buckets)
+	}
+	h.sum = o.sum
+	h.sumOfSquares = o.sumOfSquares
+	h.value = o.value
+	h.valueCount = o.valueCount
+}
+
+// Multiply scales the histogram by the specified ratio.
+func (h *histogram) Multiply(ratio float64) {
+	if h.valueCount == -1 {
+		for i := range h.buckets {
+			h.buckets[i] = int64(float64(h.buckets[i]) * ratio)
+		}
+	} else {
+		h.valueCount = int64(float64(h.valueCount) * ratio)
+	}
+	h.sum = int64(float64(h.sum) * ratio)
+	h.sumOfSquares = h.sumOfSquares * ratio
+}
+
+// New creates a new histogram.
+func (h *histogram) New() timeseries.Observable {
+	r := new(histogram)
+	r.Clear()
+	return r
+}
+
+func (h *histogram) String() string {
+	return fmt.Sprintf("%d, %f, %d, %d, %v",
+		h.sum, h.sumOfSquares, h.value, h.valueCount, h.buckets)
+}
+
+// round returns the closest int64 to the argument
+func round(in float64) int64 {
+	return int64(math.Floor(in + 0.5))
+}
+
+// bucketBoundary returns the first value in the bucket.
+func bucketBoundary(bucket uint8) int64 {
+	if bucket == 0 {
+		return 0
+	}
+	return 1 << bucket
+}
+
+// bucketData holds data about a specific bucket for use in distTmpl.
+type bucketData struct {
+	Lower, Upper       int64
+	N                  int64
+	Pct, CumulativePct float64
+	GraphWidth         int
+}
+
+// data holds data about a Distribution for use in distTmpl.
+type data struct {
+	Buckets                 []*bucketData
+	Count, Median           int64
+	Mean, StandardDeviation float64
+}
+
+// maxHTMLBarWidth is the maximum width of the HTML bar for visualizing buckets.
+const maxHTMLBarWidth = 350.0
+
+// newData returns data representing h for use in distTmpl.
+func (h *histogram) newData() *data {
+	// Force the allocation of buckets to simplify the rendering implementation
+	h.allocateBuckets()
+	// We scale the bars on the right so that the largest bar is
+	// maxHTMLBarWidth pixels in width.
+	maxBucket := int64(0)
+	for _, n := range h.buckets {
+		if n > maxBucket {
+			maxBucket = n
+		}
+	}
+	total := h.total()
+	barsizeMult := maxHTMLBarWidth / float64(maxBucket)
+	var pctMult float64
+	if total == 0 {
+		pctMult = 1.0
+	} else {
+		pctMult = 100.0 / float64(total)
+	}
+
+	buckets := make([]*bucketData, len(h.buckets))
+	runningTotal := int64(0)
+	for i, n := range h.buckets {
+		if n == 0 {
+			continue
+		}
+		runningTotal += n
+		var upperBound int64
+		if i < bucketCount-1 {
+			upperBound = bucketBoundary(uint8(i + 1))
+		} else {
+			upperBound = math.MaxInt64
+		}
+		buckets[i] = &bucketData{
+			Lower:         bucketBoundary(uint8(i)),
+			Upper:         upperBound,
+			N:             n,
+			Pct:           float64(n) * pctMult,
+			CumulativePct: float64(runningTotal) * pctMult,
+			GraphWidth:    int(float64(n) * barsizeMult),
+		}
+	}
+	return &data{
+		Buckets:           buckets,
+		Count:             total,
+		Median:            h.median(),
+		Mean:              h.average(),
+		StandardDeviation: h.standardDeviation(),
+	}
+}
+
+func (h *histogram) html() template.HTML {
+	buf := new(bytes.Buffer)
+	if err := distTmpl().Execute(buf, h.newData()); err != nil {
+		buf.Reset()
+		log.Printf("net/trace: couldn't execute template: %v", err)
+	}
+	return template.HTML(buf.String())
+}
+
+var distTmplCache *template.Template
+var distTmplOnce sync.Once
+
+func distTmpl() *template.Template {
+	distTmplOnce.Do(func() {
+		// Input: data
+		distTmplCache = template.Must(template.New("distTmpl").Parse(`
+<table>
+<tr>
+    <td style="padding:0.25em">Count: {{.Count}}</td>
+    <td style="padding:0.25em">Mean: {{printf "%.0f" .Mean}}</td>
+    <td style="padding:0.25em">StdDev: {{printf "%.0f" .StandardDeviation}}</td>
+    <td style="padding:0.25em">Median: {{.Median}}</td>
+</tr>
+</table>
+<hr>
+<table>
+{{range $b := .Buckets}}
+{{if $b}}
+  <tr>
+    <td style="padding:0 0 0 0.25em">[</td>
+    <td style="text-align:right;padding:0 0.25em">{{.Lower}},</td>
+    <td style="text-align:right;padding:0 0.25em">{{.Upper}})</td>
+    <td style="text-align:right;padding:0 0.25em">{{.N}}</td>
+    <td style="text-align:right;padding:0 0.25em">{{printf "%#.3f" .Pct}}%</td>
+    <td style="text-align:right;padding:0 0.25em">{{printf "%#.3f" .CumulativePct}}%</td>
+    <td><div style="background-color: blue; height: 1em; width: {{.GraphWidth}};"></div></td>
+  </tr>
+{{end}}
+{{end}}
+</table>
+`))
+	})
+	return distTmplCache
+}

vendor/golang.org/x/net/trace/histogram_test.go

@@ -0,0 +1,325 @@
+// 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 (
+	"math"
+	"testing"
+)
+
+type sumTest struct {
+	value        int64
+	sum          int64
+	sumOfSquares float64
+	total        int64
+}
+
+var sumTests = []sumTest{
+	{100, 100, 10000, 1},
+	{50, 150, 12500, 2},
+	{50, 200, 15000, 3},
+	{50, 250, 17500, 4},
+}
+
+type bucketingTest struct {
+	in     int64
+	log    int
+	bucket int
+}
+
+var bucketingTests = []bucketingTest{
+	{0, 0, 0},
+	{1, 1, 0},
+	{2, 2, 1},
+	{3, 2, 1},
+	{4, 3, 2},
+	{1000, 10, 9},
+	{1023, 10, 9},
+	{1024, 11, 10},
+	{1000000, 20, 19},
+}
+
+type multiplyTest struct {
+	in                   int64
+	ratio                float64
+	expectedSum          int64
+	expectedTotal        int64
+	expectedSumOfSquares float64
+}
+
+var multiplyTests = []multiplyTest{
+	{15, 2.5, 37, 2, 562.5},
+	{128, 4.6, 758, 13, 77953.9},
+}
+
+type percentileTest struct {
+	fraction float64
+	expected int64
+}
+
+var percentileTests = []percentileTest{
+	{0.25, 48},
+	{0.5, 96},
+	{0.6, 109},
+	{0.75, 128},
+	{0.90, 205},
+	{0.95, 230},
+	{0.99, 256},
+}
+
+func TestSum(t *testing.T) {
+	var h histogram
+
+	for _, test := range sumTests {
+		h.addMeasurement(test.value)
+		sum := h.sum
+		if sum != test.sum {
+			t.Errorf("h.Sum = %v WANT: %v", sum, test.sum)
+		}
+
+		sumOfSquares := h.sumOfSquares
+		if sumOfSquares != test.sumOfSquares {
+			t.Errorf("h.SumOfSquares = %v WANT: %v", sumOfSquares, test.sumOfSquares)
+		}
+
+		total := h.total()
+		if total != test.total {
+			t.Errorf("h.Total = %v WANT: %v", total, test.total)
+		}
+	}
+}
+
+func TestMultiply(t *testing.T) {
+	var h histogram
+	for i, test := range multiplyTests {
+		h.addMeasurement(test.in)
+		h.Multiply(test.ratio)
+		if h.sum != test.expectedSum {
+			t.Errorf("#%v: h.sum = %v WANT: %v", i, h.sum, test.expectedSum)
+		}
+		if h.total() != test.expectedTotal {
+			t.Errorf("#%v: h.total = %v WANT: %v", i, h.total(), test.expectedTotal)
+		}
+		if h.sumOfSquares != test.expectedSumOfSquares {
+			t.Errorf("#%v: h.SumOfSquares = %v WANT: %v", i, test.expectedSumOfSquares, h.sumOfSquares)
+		}
+	}
+}
+
+func TestBucketingFunctions(t *testing.T) {
+	for _, test := range bucketingTests {
+		log := log2(test.in)
+		if log != test.log {
+			t.Errorf("log2 = %v WANT: %v", log, test.log)
+		}
+
+		bucket := getBucket(test.in)
+		if bucket != test.bucket {
+			t.Errorf("getBucket = %v WANT: %v", bucket, test.bucket)
+		}
+	}
+}
+
+func TestAverage(t *testing.T) {
+	a := new(histogram)
+	average := a.average()
+	if average != 0 {
+		t.Errorf("Average of empty histogram was %v WANT: 0", average)
+	}
+
+	a.addMeasurement(1)
+	a.addMeasurement(1)
+	a.addMeasurement(3)
+	const expected = float64(5) / float64(3)
+	average = a.average()
+
+	if !isApproximate(average, expected) {
+		t.Errorf("Average = %g WANT: %v", average, expected)
+	}
+}
+
+func TestStandardDeviation(t *testing.T) {
+	a := new(histogram)
+	add(a, 10, 1<<4)
+	add(a, 10, 1<<5)
+	add(a, 10, 1<<6)
+	stdDev := a.standardDeviation()
+	const expected = 19.95
+
+	if !isApproximate(stdDev, expected) {
+		t.Errorf("StandardDeviation = %v WANT: %v", stdDev, expected)
+	}
+
+	// No values
+	a = new(histogram)
+	stdDev = a.standardDeviation()
+
+	if !isApproximate(stdDev, 0) {
+		t.Errorf("StandardDeviation = %v WANT: 0", stdDev)
+	}
+
+	add(a, 1, 1<<4)
+	if !isApproximate(stdDev, 0) {
+		t.Errorf("StandardDeviation = %v WANT: 0", stdDev)
+	}
+
+	add(a, 10, 1<<4)
+	if !isApproximate(stdDev, 0) {
+		t.Errorf("StandardDeviation = %v WANT: 0", stdDev)
+	}
+}
+
+func TestPercentileBoundary(t *testing.T) {
+	a := new(histogram)
+	add(a, 5, 1<<4)
+	add(a, 10, 1<<6)
+	add(a, 5, 1<<7)
+
+	for _, test := range percentileTests {
+		percentile := a.percentileBoundary(test.fraction)
+		if percentile != test.expected {
+			t.Errorf("h.PercentileBoundary (fraction=%v) = %v WANT: %v", test.fraction, percentile, test.expected)
+		}
+	}
+}
+
+func TestCopyFrom(t *testing.T) {
+	a := histogram{5, 25, []int64{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
+		19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38}, 4, -1}
+	b := histogram{6, 36, []int64{2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
+		20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39}, 5, -1}
+
+	a.CopyFrom(&b)
+
+	if a.String() != b.String() {
+		t.Errorf("a.String = %s WANT: %s", a.String(), b.String())
+	}
+}
+
+func TestClear(t *testing.T) {
+	a := histogram{5, 25, []int64{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
+		19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38}, 4, -1}
+
+	a.Clear()
+
+	expected := "0, 0.000000, 0, 0, []"
+	if a.String() != expected {
+		t.Errorf("a.String = %s WANT %s", a.String(), expected)
+	}
+}
+
+func TestNew(t *testing.T) {
+	a := histogram{5, 25, []int64{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
+		19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38}, 4, -1}
+	b := a.New()
+
+	expected := "0, 0.000000, 0, 0, []"
+	if b.(*histogram).String() != expected {
+		t.Errorf("b.(*histogram).String = %s WANT: %s", b.(*histogram).String(), expected)
+	}
+}
+
+func TestAdd(t *testing.T) {
+	// The tests here depend on the associativity of addMeasurement and Add.
+	// Add empty observation
+	a := histogram{5, 25, []int64{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
+		19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38}, 4, -1}
+	b := a.New()
+
+	expected := a.String()
+	a.Add(b)
+	if a.String() != expected {
+		t.Errorf("a.String = %s WANT: %s", a.String(), expected)
+	}
+
+	// Add same bucketed value, no new buckets
+	c := new(histogram)
+	d := new(histogram)
+	e := new(histogram)
+	c.addMeasurement(12)
+	d.addMeasurement(11)
+	e.addMeasurement(12)
+	e.addMeasurement(11)
+	c.Add(d)
+	if c.String() != e.String() {
+		t.Errorf("c.String = %s WANT: %s", c.String(), e.String())
+	}
+
+	// Add bucketed values
+	f := new(histogram)
+	g := new(histogram)
+	h := new(histogram)
+	f.addMeasurement(4)
+	f.addMeasurement(12)
+	f.addMeasurement(100)
+	g.addMeasurement(18)
+	g.addMeasurement(36)
+	g.addMeasurement(255)
+	h.addMeasurement(4)
+	h.addMeasurement(12)
+	h.addMeasurement(100)
+	h.addMeasurement(18)
+	h.addMeasurement(36)
+	h.addMeasurement(255)
+	f.Add(g)
+	if f.String() != h.String() {
+		t.Errorf("f.String = %q WANT: %q", f.String(), h.String())
+	}
+
+	// add buckets to no buckets
+	i := new(histogram)
+	j := new(histogram)
+	k := new(histogram)
+	j.addMeasurement(18)
+	j.addMeasurement(36)
+	j.addMeasurement(255)
+	k.addMeasurement(18)
+	k.addMeasurement(36)
+	k.addMeasurement(255)
+	i.Add(j)
+	if i.String() != k.String() {
+		t.Errorf("i.String = %q WANT: %q", i.String(), k.String())
+	}
+
+	// add buckets to single value (no overlap)
+	l := new(histogram)
+	m := new(histogram)
+	n := new(histogram)
+	l.addMeasurement(0)
+	m.addMeasurement(18)
+	m.addMeasurement(36)
+	m.addMeasurement(255)
+	n.addMeasurement(0)
+	n.addMeasurement(18)
+	n.addMeasurement(36)
+	n.addMeasurement(255)
+	l.Add(m)
+	if l.String() != n.String() {
+		t.Errorf("l.String = %q WANT: %q", l.String(), n.String())
+	}
+
+	// mixed order
+	o := new(histogram)
+	p := new(histogram)
+	o.addMeasurement(0)
+	o.addMeasurement(2)
+	o.addMeasurement(0)
+	p.addMeasurement(0)
+	p.addMeasurement(0)
+	p.addMeasurement(2)
+	if o.String() != p.String() {
+		t.Errorf("o.String = %q WANT: %q", o.String(), p.String())
+	}
+}
+
+func add(h *histogram, times int, val int64) {
+	for i := 0; i < times; i++ {
+		h.addMeasurement(val)
+	}
+}
+
+func isApproximate(x, y float64) bool {
+	return math.Abs(x-y) < 1e-2
+}

vendor/golang.org/x/net/trace/trace_go16.go

@@ -0,0 +1,21 @@
+// Copyright 2017 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.
+
+// +build !go1.7
+
+package trace
+
+import "golang.org/x/net/context"
+
+// NewContext returns a copy of the parent context
+// and associates it with a Trace.
+func NewContext(ctx context.Context, tr Trace) context.Context {
+	return context.WithValue(ctx, contextKey, tr)
+}
+
+// FromContext returns the Trace bound to the context, if any.
+func FromContext(ctx context.Context) (tr Trace, ok bool) {
+	tr, ok = ctx.Value(contextKey).(Trace)
+	return
+}

vendor/golang.org/x/net/trace/trace_go17.go

@@ -0,0 +1,21 @@
+// Copyright 2017 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.
+
+// +build go1.7
+
+package trace
+
+import "context"
+
+// NewContext returns a copy of the parent context
+// and associates it with a Trace.
+func NewContext(ctx context.Context, tr Trace) context.Context {
+	return context.WithValue(ctx, contextKey, tr)
+}
+
+// FromContext returns the Trace bound to the context, if any.
+func FromContext(ctx context.Context) (tr Trace, ok bool) {
+	tr, ok = ctx.Value(contextKey).(Trace)
+	return
+}

vendor/golang.org/x/net/trace/trace_test.go

@@ -0,0 +1,178 @@
+// 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 (
+	"net/http"
+	"reflect"
+	"testing"
+)
+
+type s struct{}
+
+func (s) String() string { return "lazy string" }
+
+// TestReset checks whether all the fields are zeroed after reset.
+func TestReset(t *testing.T) {
+	tr := New("foo", "bar")
+	tr.LazyLog(s{}, false)
+	tr.LazyPrintf("%d", 1)
+	tr.SetRecycler(func(_ interface{}) {})
+	tr.SetTraceInfo(3, 4)
+	tr.SetMaxEvents(100)
+	tr.SetError()
+	tr.Finish()
+
+	tr.(*trace).reset()
+
+	if !reflect.DeepEqual(tr, new(trace)) {
+		t.Errorf("reset didn't clear all fields: %+v", tr)
+	}
+}
+
+// TestResetLog checks whether all the fields are zeroed after reset.
+func TestResetLog(t *testing.T) {
+	el := NewEventLog("foo", "bar")
+	el.Printf("message")
+	el.Errorf("error")
+	el.Finish()
+
+	el.(*eventLog).reset()
+
+	if !reflect.DeepEqual(el, new(eventLog)) {
+		t.Errorf("reset didn't clear all fields: %+v", el)
+	}
+}
+
+func TestAuthRequest(t *testing.T) {
+	testCases := []struct {
+		host string
+		want bool
+	}{
+		{host: "192.168.23.1", want: false},
+		{host: "192.168.23.1:8080", want: false},
+		{host: "malformed remote addr", want: false},
+		{host: "localhost", want: true},
+		{host: "localhost:8080", want: true},
+		{host: "127.0.0.1", want: true},
+		{host: "127.0.0.1:8080", want: true},
+		{host: "::1", want: true},
+		{host: "[::1]:8080", want: true},
+	}
+	for _, tt := range testCases {
+		req := &http.Request{RemoteAddr: tt.host}
+		any, sensitive := AuthRequest(req)
+		if any != tt.want || sensitive != tt.want {
+			t.Errorf("AuthRequest(%q) = %t, %t; want %t, %t", tt.host, any, sensitive, tt.want, tt.want)
+		}
+	}
+}
+
+// TestParseTemplate checks that all templates used by this package are valid
+// as they are parsed on first usage
+func TestParseTemplate(t *testing.T) {
+	if tmpl := distTmpl(); tmpl == nil {
+		t.Error("invalid template returned from distTmpl()")
+	}
+	if tmpl := pageTmpl(); tmpl == nil {
+		t.Error("invalid template returned from pageTmpl()")
+	}
+	if tmpl := eventsTmpl(); tmpl == nil {
+		t.Error("invalid template returned from eventsTmpl()")
+	}
+}
+
+func benchmarkTrace(b *testing.B, maxEvents, numEvents int) {
+	numSpans := (b.N + numEvents + 1) / numEvents
+
+	for i := 0; i < numSpans; i++ {
+		tr := New("test", "test")
+		tr.SetMaxEvents(maxEvents)
+		for j := 0; j < numEvents; j++ {
+			tr.LazyPrintf("%d", j)
+		}
+		tr.Finish()
+	}
+}
+
+func BenchmarkTrace_Default_2(b *testing.B) {
+	benchmarkTrace(b, 0, 2)
+}
+
+func BenchmarkTrace_Default_10(b *testing.B) {
+	benchmarkTrace(b, 0, 10)
+}
+
+func BenchmarkTrace_Default_100(b *testing.B) {
+	benchmarkTrace(b, 0, 100)
+}
+
+func BenchmarkTrace_Default_1000(b *testing.B) {
+	benchmarkTrace(b, 0, 1000)
+}
+
+func BenchmarkTrace_Default_10000(b *testing.B) {
+	benchmarkTrace(b, 0, 10000)
+}
+
+func BenchmarkTrace_10_2(b *testing.B) {
+	benchmarkTrace(b, 10, 2)
+}
+
+func BenchmarkTrace_10_10(b *testing.B) {
+	benchmarkTrace(b, 10, 10)
+}
+
+func BenchmarkTrace_10_100(b *testing.B) {
+	benchmarkTrace(b, 10, 100)
+}
+
+func BenchmarkTrace_10_1000(b *testing.B) {
+	benchmarkTrace(b, 10, 1000)
+}
+
+func BenchmarkTrace_10_10000(b *testing.B) {
+	benchmarkTrace(b, 10, 10000)
+}
+
+func BenchmarkTrace_100_2(b *testing.B) {
+	benchmarkTrace(b, 100, 2)
+}
+
+func BenchmarkTrace_100_10(b *testing.B) {
+	benchmarkTrace(b, 100, 10)
+}
+
+func BenchmarkTrace_100_100(b *testing.B) {
+	benchmarkTrace(b, 100, 100)
+}
+
+func BenchmarkTrace_100_1000(b *testing.B) {
+	benchmarkTrace(b, 100, 1000)
+}
+
+func BenchmarkTrace_100_10000(b *testing.B) {
+	benchmarkTrace(b, 100, 10000)
+}
+
+func BenchmarkTrace_1000_2(b *testing.B) {
+	benchmarkTrace(b, 1000, 2)
+}
+
+func BenchmarkTrace_1000_10(b *testing.B) {
+	benchmarkTrace(b, 1000, 10)
+}
+
+func BenchmarkTrace_1000_100(b *testing.B) {
+	benchmarkTrace(b, 1000, 100)
+}
+
+func BenchmarkTrace_1000_1000(b *testing.B) {
+	benchmarkTrace(b, 1000, 1000)
+}
+
+func BenchmarkTrace_1000_10000(b *testing.B) {
+	benchmarkTrace(b, 1000, 10000)
+}