diff options
Diffstat (limited to 'vendor/golang.org/x/net/trace')
| -rw-r--r-- | vendor/golang.org/x/net/trace/events.go | 532 | ||||
| -rw-r--r-- | vendor/golang.org/x/net/trace/histogram.go | 365 | ||||
| -rw-r--r-- | vendor/golang.org/x/net/trace/trace.go | 1130 |
3 files changed, 2027 insertions, 0 deletions
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> +` diff --git a/vendor/golang.org/x/net/trace/histogram.go b/vendor/golang.org/x/net/trace/histogram.go new file mode 100644 index 0000000..9bf4286 --- /dev/null +++ b/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 +} diff --git a/vendor/golang.org/x/net/trace/trace.go b/vendor/golang.org/x/net/trace/trace.go new file mode 100644 index 0000000..eae2a99 --- /dev/null +++ b/vendor/golang.org/x/net/trace/trace.go @@ -0,0 +1,1130 @@ +// 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 implements tracing of requests and long-lived objects. +It exports HTTP interfaces on /debug/requests and /debug/events. + +A trace.Trace provides tracing for short-lived objects, usually requests. +A request handler might be implemented like this: + + func fooHandler(w http.ResponseWriter, req *http.Request) { + tr := trace.New("mypkg.Foo", req.URL.Path) + defer tr.Finish() + ... + tr.LazyPrintf("some event %q happened", str) + ... + if err := somethingImportant(); err != nil { + tr.LazyPrintf("somethingImportant failed: %v", err) + tr.SetError() + } + } + +The /debug/requests HTTP endpoint organizes the traces by family, +errors, and duration. It also provides histogram of request duration +for each family. + +A trace.EventLog provides tracing for long-lived objects, such as RPC +connections. + + // A Fetcher fetches URL paths for a single domain. + type Fetcher struct { + domain string + events trace.EventLog + } + + func NewFetcher(domain string) *Fetcher { + return &Fetcher{ + domain, + trace.NewEventLog("mypkg.Fetcher", domain), + } + } + + func (f *Fetcher) Fetch(path string) (string, error) { + resp, err := http.Get("http://" + f.domain + "/" + path) + if err != nil { + f.events.Errorf("Get(%q) = %v", path, err) + return "", err + } + f.events.Printf("Get(%q) = %s", path, resp.Status) + ... + } + + func (f *Fetcher) Close() error { + f.events.Finish() + return nil + } + +The /debug/events HTTP endpoint organizes the event logs by family and +by time since the last error. The expanded view displays recent log +entries and the log's call stack. +*/ +package trace // import "golang.org/x/net/trace" + +import ( + "bytes" + "context" + "fmt" + "html/template" + "io" + "log" + "net" + "net/http" + "net/url" + "runtime" + "sort" + "strconv" + "sync" + "sync/atomic" + "time" + + "golang.org/x/net/internal/timeseries" +) + +// DebugUseAfterFinish controls whether to debug uses of Trace values after finishing. +// FOR DEBUGGING ONLY. This will slow down the program. +var DebugUseAfterFinish = false + +// HTTP ServeMux paths. +const ( + debugRequestsPath = "/debug/requests" + debugEventsPath = "/debug/events" +) + +// AuthRequest determines whether a specific request is permitted to load the +// /debug/requests or /debug/events pages. +// +// It returns two bools; the first indicates whether the page may be viewed at all, +// and the second indicates whether sensitive events will be shown. +// +// AuthRequest may be replaced by a program to customize its authorization requirements. +// +// The default AuthRequest function returns (true, true) if and only if the request +// comes from localhost/127.0.0.1/[::1]. +var AuthRequest = func(req *http.Request) (any, sensitive bool) { + // RemoteAddr is commonly in the form "IP" or "IP:port". + // If it is in the form "IP:port", split off the port. + host, _, err := net.SplitHostPort(req.RemoteAddr) + if err != nil { + host = req.RemoteAddr + } + switch host { + case "localhost", "127.0.0.1", "::1": + return true, true + default: + return false, false + } +} + +func init() { + _, pat := http.DefaultServeMux.Handler(&http.Request{URL: &url.URL{Path: debugRequestsPath}}) + if pat == debugRequestsPath { + panic("/debug/requests is already registered. You may have two independent copies of " + + "golang.org/x/net/trace in your binary, trying to maintain separate state. This may " + + "involve a vendored copy of golang.org/x/net/trace.") + } + + // TODO(jbd): Serve Traces from /debug/traces in the future? + // There is no requirement for a request to be present to have traces. + http.HandleFunc(debugRequestsPath, Traces) + http.HandleFunc(debugEventsPath, Events) +} + +// 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 +} + +// Traces responds with traces from the program. +// The package initialization registers it in http.DefaultServeMux +// at /debug/requests. +// +// It performs authorization by running AuthRequest. +func Traces(w http.ResponseWriter, req *http.Request) { + any, sensitive := AuthRequest(req) + if !any { + http.Error(w, "not allowed", http.StatusUnauthorized) + return + } + w.Header().Set("Content-Type", "text/html; charset=utf-8") + Render(w, req, sensitive) +} + +// Events responds with a page of events collected by EventLogs. +// The package initialization registers it in http.DefaultServeMux +// at /debug/events. +// +// It performs authorization by running AuthRequest. +func Events(w http.ResponseWriter, req *http.Request) { + any, sensitive := AuthRequest(req) + if !any { + http.Error(w, "not allowed", http.StatusUnauthorized) + return + } + w.Header().Set("Content-Type", "text/html; charset=utf-8") + RenderEvents(w, req, sensitive) +} + +// Render renders the HTML page typically served at /debug/requests. +// It does not do any auth checking. The request may be nil. +// +// Most users will use the Traces handler. +func Render(w io.Writer, req *http.Request, sensitive bool) { + data := &struct { + Families []string + ActiveTraceCount map[string]int + CompletedTraces map[string]*family + + // Set when a bucket has been selected. + Traces traceList + Family string + Bucket int + Expanded bool + Traced bool + Active bool + ShowSensitive bool // whether to show sensitive events + + Histogram template.HTML + HistogramWindow string // e.g. "last minute", "last hour", "all time" + + // If non-zero, the set of traces is a partial set, + // and this is the total number. + Total int + }{ + CompletedTraces: completedTraces, + } + + data.ShowSensitive = sensitive + if req != nil { + // Allow show_sensitive=0 to force hiding of sensitive data for testing. + // This only goes one way; you can't use show_sensitive=1 to see things. + if req.FormValue("show_sensitive") == "0" { + data.ShowSensitive = false + } + + if exp, err := strconv.ParseBool(req.FormValue("exp")); err == nil { + data.Expanded = exp + } + if exp, err := strconv.ParseBool(req.FormValue("rtraced")); err == nil { + data.Traced = exp + } + } + + completedMu.RLock() + data.Families = make([]string, 0, len(completedTraces)) + for fam := range completedTraces { + data.Families = append(data.Families, fam) + } + completedMu.RUnlock() + sort.Strings(data.Families) + + // We are careful here to minimize the time spent locking activeMu, + // since that lock is required every time an RPC starts and finishes. + data.ActiveTraceCount = make(map[string]int, len(data.Families)) + activeMu.RLock() + for fam, s := range activeTraces { + data.ActiveTraceCount[fam] = s.Len() + } + activeMu.RUnlock() + + var ok bool + data.Family, data.Bucket, ok = parseArgs(req) + switch { + case !ok: + // No-op + case data.Bucket == -1: + data.Active = true + n := data.ActiveTraceCount[data.Family] + data.Traces = getActiveTraces(data.Family) + if len(data.Traces) < n { + data.Total = n + } + case data.Bucket < bucketsPerFamily: + if b := lookupBucket(data.Family, data.Bucket); b != nil { + data.Traces = b.Copy(data.Traced) + } + default: + if f := getFamily(data.Family, false); f != nil { + var obs timeseries.Observable + f.LatencyMu.RLock() + switch o := data.Bucket - bucketsPerFamily; o { + case 0: + obs = f.Latency.Minute() + data.HistogramWindow = "last minute" + case 1: + obs = f.Latency.Hour() + data.HistogramWindow = "last hour" + case 2: + obs = f.Latency.Total() + data.HistogramWindow = "all time" + } + f.LatencyMu.RUnlock() + if obs != nil { + data.Histogram = obs.(*histogram).html() + } + } + } + + if data.Traces != nil { + defer data.Traces.Free() + sort.Sort(data.Traces) + } + + completedMu.RLock() + defer completedMu.RUnlock() + if err := pageTmpl().ExecuteTemplate(w, "Page", data); err != nil { + log.Printf("net/trace: Failed executing template: %v", err) + } +} + +func parseArgs(req *http.Request) (fam string, b int, ok bool) { + if req == nil { + return "", 0, false + } + fam, bStr := req.FormValue("fam"), req.FormValue("b") + if fam == "" || bStr == "" { + return "", 0, false + } + b, err := strconv.Atoi(bStr) + if err != nil || b < -1 { + return "", 0, false + } + + return fam, b, true +} + +func lookupBucket(fam string, b int) *traceBucket { + f := getFamily(fam, false) + if f == nil || b < 0 || b >= len(f.Buckets) { + return nil + } + return f.Buckets[b] +} + +type contextKeyT string + +var contextKey = contextKeyT("golang.org/x/net/trace.Trace") + +// Trace represents an active request. +type Trace interface { + // LazyLog adds x to the event log. It will be evaluated each time the + // /debug/requests page is rendered. Any memory referenced by x will be + // pinned until the trace is finished and later discarded. + LazyLog(x fmt.Stringer, sensitive bool) + + // LazyPrintf evaluates its arguments with fmt.Sprintf each time the + // /debug/requests page is rendered. Any memory referenced by a will be + // pinned until the trace is finished and later discarded. + LazyPrintf(format string, a ...interface{}) + + // SetError declares that this trace resulted in an error. + SetError() + + // SetRecycler sets a recycler for the trace. + // f will be called for each event passed to LazyLog at a time when + // it is no longer required, whether while the trace is still active + // and the event is discarded, or when a completed trace is discarded. + SetRecycler(f func(interface{})) + + // SetTraceInfo sets the trace info for the trace. + // This is currently unused. + SetTraceInfo(traceID, spanID uint64) + + // SetMaxEvents sets the maximum number of events that will be stored + // in the trace. This has no effect if any events have already been + // added to the trace. + SetMaxEvents(m int) + + // Finish declares that this trace is complete. + // The trace should not be used after calling this method. + Finish() +} + +type lazySprintf struct { + format string + a []interface{} +} + +func (l *lazySprintf) String() string { + return fmt.Sprintf(l.format, l.a...) +} + +// New returns a new Trace with the specified family and title. +func New(family, title string) Trace { + tr := newTrace() + tr.ref() + tr.Family, tr.Title = family, title + tr.Start = time.Now() + tr.maxEvents = maxEventsPerTrace + tr.events = tr.eventsBuf[:0] + + activeMu.RLock() + s := activeTraces[tr.Family] + activeMu.RUnlock() + if s == nil { + activeMu.Lock() + s = activeTraces[tr.Family] // check again + if s == nil { + s = new(traceSet) + activeTraces[tr.Family] = s + } + activeMu.Unlock() + } + s.Add(tr) + + // Trigger allocation of the completed trace structure for this family. + // This will cause the family to be present in the request page during + // the first trace of this family. We don't care about the return value, + // nor is there any need for this to run inline, so we execute it in its + // own goroutine, but only if the family isn't allocated yet. + completedMu.RLock() + if _, ok := completedTraces[tr.Family]; !ok { + go allocFamily(tr.Family) + } + completedMu.RUnlock() + + return tr +} + +func (tr *trace) Finish() { + elapsed := time.Since(tr.Start) + tr.mu.Lock() + tr.Elapsed = elapsed + tr.mu.Unlock() + + if DebugUseAfterFinish { + buf := make([]byte, 4<<10) // 4 KB should be enough + n := runtime.Stack(buf, false) + tr.finishStack = buf[:n] + } + + activeMu.RLock() + m := activeTraces[tr.Family] + activeMu.RUnlock() + m.Remove(tr) + + f := getFamily(tr.Family, true) + tr.mu.RLock() // protects tr fields in Cond.match calls + for _, b := range f.Buckets { + if b.Cond.match(tr) { + b.Add(tr) + } + } + tr.mu.RUnlock() + + // Add a sample of elapsed time as microseconds to the family's timeseries + h := new(histogram) + h.addMeasurement(elapsed.Nanoseconds() / 1e3) + f.LatencyMu.Lock() + f.Latency.Add(h) + f.LatencyMu.Unlock() + + tr.unref() // matches ref in New +} + +const ( + bucketsPerFamily = 9 + tracesPerBucket = 10 + maxActiveTraces = 20 // Maximum number of active traces to show. + maxEventsPerTrace = 10 + numHistogramBuckets = 38 +) + +var ( + // The active traces. + activeMu sync.RWMutex + activeTraces = make(map[string]*traceSet) // family -> traces + + // Families of completed traces. + completedMu sync.RWMutex + completedTraces = make(map[string]*family) // family -> traces +) + +type traceSet struct { + mu sync.RWMutex + m map[*trace]bool + + // We could avoid the entire map scan in FirstN by having a slice of all the traces + // ordered by start time, and an index into that from the trace struct, with a periodic + // repack of the slice after enough traces finish; we could also use a skip list or similar. + // However, that would shift some of the expense from /debug/requests time to RPC time, + // which is probably the wrong trade-off. +} + +func (ts *traceSet) Len() int { + ts.mu.RLock() + defer ts.mu.RUnlock() + return len(ts.m) +} + +func (ts *traceSet) Add(tr *trace) { + ts.mu.Lock() + if ts.m == nil { + ts.m = make(map[*trace]bool) + } + ts.m[tr] = true + ts.mu.Unlock() +} + +func (ts *traceSet) Remove(tr *trace) { + ts.mu.Lock() + delete(ts.m, tr) + ts.mu.Unlock() +} + +// FirstN returns the first n traces ordered by time. +func (ts *traceSet) FirstN(n int) traceList { + ts.mu.RLock() + defer ts.mu.RUnlock() + + if n > len(ts.m) { + n = len(ts.m) + } + trl := make(traceList, 0, n) + + // Fast path for when no selectivity is needed. + if n == len(ts.m) { + for tr := range ts.m { + tr.ref() + trl = append(trl, tr) + } + sort.Sort(trl) + return trl + } + + // Pick the oldest n traces. + // This is inefficient. See the comment in the traceSet struct. + for tr := range ts.m { + // Put the first n traces into trl in the order they occur. + // When we have n, sort trl, and thereafter maintain its order. + if len(trl) < n { + tr.ref() + trl = append(trl, tr) + if len(trl) == n { + // This is guaranteed to happen exactly once during this loop. + sort.Sort(trl) + } + continue + } + if tr.Start.After(trl[n-1].Start) { + continue + } + + // Find where to insert this one. + tr.ref() + i := sort.Search(n, func(i int) bool { return trl[i].Start.After(tr.Start) }) + trl[n-1].unref() + copy(trl[i+1:], trl[i:]) + trl[i] = tr + } + + return trl +} + +func getActiveTraces(fam string) traceList { + activeMu.RLock() + s := activeTraces[fam] + activeMu.RUnlock() + if s == nil { + return nil + } + return s.FirstN(maxActiveTraces) +} + +func getFamily(fam string, allocNew bool) *family { + completedMu.RLock() + f := completedTraces[fam] + completedMu.RUnlock() + if f == nil && allocNew { + f = allocFamily(fam) + } + return f +} + +func allocFamily(fam string) *family { + completedMu.Lock() + defer completedMu.Unlock() + f := completedTraces[fam] + if f == nil { + f = newFamily() + completedTraces[fam] = f + } + return f +} + +// family represents a set of trace buckets and associated latency information. +type family struct { + // traces may occur in multiple buckets. + Buckets [bucketsPerFamily]*traceBucket + + // latency time series + LatencyMu sync.RWMutex + Latency *timeseries.MinuteHourSeries +} + +func newFamily() *family { + return &family{ + Buckets: [bucketsPerFamily]*traceBucket{ + {Cond: minCond(0)}, + {Cond: minCond(50 * time.Millisecond)}, + {Cond: minCond(100 * time.Millisecond)}, + {Cond: minCond(200 * time.Millisecond)}, + {Cond: minCond(500 * time.Millisecond)}, + {Cond: minCond(1 * time.Second)}, + {Cond: minCond(10 * time.Second)}, + {Cond: minCond(100 * time.Second)}, + {Cond: errorCond{}}, + }, + Latency: timeseries.NewMinuteHourSeries(func() timeseries.Observable { return new(histogram) }), + } +} + +// traceBucket represents a size-capped bucket of historic traces, +// along with a condition for a trace to belong to the bucket. +type traceBucket struct { + Cond cond + + // Ring buffer implementation of a fixed-size FIFO queue. + mu sync.RWMutex + buf [tracesPerBucket]*trace + start int // < tracesPerBucket + length int // <= tracesPerBucket +} + +func (b *traceBucket) Add(tr *trace) { + b.mu.Lock() + defer b.mu.Unlock() + + i := b.start + b.length + if i >= tracesPerBucket { + i -= tracesPerBucket + } + if b.length == tracesPerBucket { + // "Remove" an element from the bucket. + b.buf[i].unref() + b.start++ + if b.start == tracesPerBucket { + b.start = 0 + } + } + b.buf[i] = tr + if b.length < tracesPerBucket { + b.length++ + } + tr.ref() +} + +// Copy returns a copy of the traces in the bucket. +// If tracedOnly is true, only the traces with trace information will be returned. +// The logs will be ref'd before returning; the caller should call +// the Free method when it is done with them. +// TODO(dsymonds): keep track of traced requests in separate buckets. +func (b *traceBucket) Copy(tracedOnly bool) traceList { + b.mu.RLock() + defer b.mu.RUnlock() + + trl := make(traceList, 0, b.length) + for i, x := 0, b.start; i < b.length; i++ { + tr := b.buf[x] + if !tracedOnly || tr.spanID != 0 { + tr.ref() + trl = append(trl, tr) + } + x++ + if x == b.length { + x = 0 + } + } + return trl +} + +func (b *traceBucket) Empty() bool { + b.mu.RLock() + defer b.mu.RUnlock() + return b.length == 0 +} + +// cond represents a condition on a trace. +type cond interface { + match(t *trace) bool + String() string +} + +type minCond time.Duration + +func (m minCond) match(t *trace) bool { return t.Elapsed >= time.Duration(m) } +func (m minCond) String() string { return fmt.Sprintf("≥%gs", time.Duration(m).Seconds()) } + +type errorCond struct{} + +func (e errorCond) match(t *trace) bool { return t.IsError } +func (e errorCond) String() string { return "errors" } + +type traceList []*trace + +// Free calls unref on each element of the list. +func (trl traceList) Free() { + for _, t := range trl { + t.unref() + } +} + +// traceList may be sorted in reverse chronological order. +func (trl traceList) Len() int { return len(trl) } +func (trl traceList) Less(i, j int) bool { return trl[i].Start.After(trl[j].Start) } +func (trl traceList) Swap(i, j int) { trl[i], trl[j] = trl[j], trl[i] } + +// An event is a timestamped log entry in a trace. +type event struct { + When time.Time + Elapsed time.Duration // since previous event in trace + NewDay bool // whether this event is on a different day to the previous event + Recyclable bool // whether this event was passed via LazyLog + Sensitive bool // whether this event contains sensitive information + What interface{} // string or fmt.Stringer +} + +// WhenString returns a string representation of the elapsed time of the event. +// It will include the date if midnight was crossed. +func (e event) WhenString() string { + if e.NewDay { + return e.When.Format("2006/01/02 15:04:05.000000") + } + return e.When.Format("15:04:05.000000") +} + +// discarded represents a number of discarded events. +// It is stored as *discarded to make it easier to update in-place. +type discarded int + +func (d *discarded) String() string { + return fmt.Sprintf("(%d events discarded)", int(*d)) +} + +// trace represents an active or complete request, +// either sent or received by this program. +type trace struct { + // Family is the top-level grouping of traces to which this belongs. + Family string + + // Title is the title of this trace. + Title string + + // Start time of the this trace. + Start time.Time + + mu sync.RWMutex + events []event // Append-only sequence of events (modulo discards). + maxEvents int + recycler func(interface{}) + IsError bool // Whether this trace resulted in an error. + Elapsed time.Duration // Elapsed time for this trace, zero while active. + traceID uint64 // Trace information if non-zero. + spanID uint64 + + refs int32 // how many buckets this is in + disc discarded // scratch space to avoid allocation + + finishStack []byte // where finish was called, if DebugUseAfterFinish is set + + eventsBuf [4]event // preallocated buffer in case we only log a few events +} + +func (tr *trace) reset() { + // Clear all but the mutex. Mutexes may not be copied, even when unlocked. + tr.Family = "" + tr.Title = "" + tr.Start = time.Time{} + + tr.mu.Lock() + tr.Elapsed = 0 + tr.traceID = 0 + tr.spanID = 0 + tr.IsError = false + tr.maxEvents = 0 + tr.events = nil + tr.recycler = nil + tr.mu.Unlock() + + tr.refs = 0 + tr.disc = 0 + tr.finishStack = nil + for i := range tr.eventsBuf { + tr.eventsBuf[i] = event{} + } +} + +// delta returns the elapsed time since the last event or the trace start, +// and whether it spans midnight. +// L >= tr.mu +func (tr *trace) delta(t time.Time) (time.Duration, bool) { + if len(tr.events) == 0 { + return t.Sub(tr.Start), false + } + prev := tr.events[len(tr.events)-1].When + return t.Sub(prev), prev.Day() != t.Day() +} + +func (tr *trace) addEvent(x interface{}, recyclable, sensitive bool) { + if DebugUseAfterFinish && tr.finishStack != nil { + buf := make([]byte, 4<<10) // 4 KB should be enough + n := runtime.Stack(buf, false) + log.Printf("net/trace: trace used after finish:\nFinished at:\n%s\nUsed at:\n%s", tr.finishStack, buf[:n]) + } + + /* + NOTE TO DEBUGGERS + + If you are here because your program panicked in this code, + it is almost definitely the fault of code using this package, + and very unlikely to be the fault of this code. + + The most likely scenario is that some code elsewhere is using + a trace.Trace after its Finish method is called. + You can temporarily set the DebugUseAfterFinish var + to help discover where that is; do not leave that var set, + since it makes this package much less efficient. + */ + + e := event{When: time.Now(), What: x, Recyclable: recyclable, Sensitive: sensitive} + tr.mu.Lock() + e.Elapsed, e.NewDay = tr.delta(e.When) + if len(tr.events) < tr.maxEvents { + tr.events = append(tr.events, e) + } else { + // Discard the middle events. + di := int((tr.maxEvents - 1) / 2) + if d, ok := tr.events[di].What.(*discarded); ok { + (*d)++ + } else { + // disc starts at two to count for the event it is replacing, + // plus the next one that we are about to drop. + tr.disc = 2 + if tr.recycler != nil && tr.events[di].Recyclable { + go tr.recycler(tr.events[di].What) + } + tr.events[di].What = &tr.disc + } + // The timestamp of the discarded meta-event should be + // the time of the last event it is representing. + tr.events[di].When = tr.events[di+1].When + + if tr.recycler != nil && tr.events[di+1].Recyclable { + go tr.recycler(tr.events[di+1].What) + } + copy(tr.events[di+1:], tr.events[di+2:]) + tr.events[tr.maxEvents-1] = e + } + tr.mu.Unlock() +} + +func (tr *trace) LazyLog(x fmt.Stringer, sensitive bool) { + tr.addEvent(x, true, sensitive) +} + +func (tr *trace) LazyPrintf(format string, a ...interface{}) { + tr.addEvent(&lazySprintf{format, a}, false, false) +} + +func (tr *trace) SetError() { + tr.mu.Lock() + tr.IsError = true + tr.mu.Unlock() +} + +func (tr *trace) SetRecycler(f func(interface{})) { + tr.mu.Lock() + tr.recycler = f + tr.mu.Unlock() +} + +func (tr *trace) SetTraceInfo(traceID, spanID uint64) { + tr.mu.Lock() + tr.traceID, tr.spanID = traceID, spanID + tr.mu.Unlock() +} + +func (tr *trace) SetMaxEvents(m int) { + tr.mu.Lock() + // Always keep at least three events: first, discarded count, last. + if len(tr.events) == 0 && m > 3 { + tr.maxEvents = m + } + tr.mu.Unlock() +} + +func (tr *trace) ref() { + atomic.AddInt32(&tr.refs, 1) +} + +func (tr *trace) unref() { + if atomic.AddInt32(&tr.refs, -1) == 0 { + tr.mu.RLock() + if tr.recycler != nil { + // freeTrace clears tr, so we hold tr.recycler and tr.events here. + go func(f func(interface{}), es []event) { + for _, e := range es { + if e.Recyclable { + f(e.What) + } + } + }(tr.recycler, tr.events) + } + tr.mu.RUnlock() + + freeTrace(tr) + } +} + +func (tr *trace) When() string { + return tr.Start.Format("2006/01/02 15:04:05.000000") +} + +func (tr *trace) ElapsedTime() string { + tr.mu.RLock() + t := tr.Elapsed + tr.mu.RUnlock() + + if t == 0 { + // Active trace. + t = time.Since(tr.Start) + } + return fmt.Sprintf("%.6f", t.Seconds()) +} + +func (tr *trace) Events() []event { + tr.mu.RLock() + defer tr.mu.RUnlock() + return tr.events +} + +var traceFreeList = make(chan *trace, 1000) // TODO(dsymonds): Use sync.Pool? + +// newTrace returns a trace ready to use. +func newTrace() *trace { + select { + case tr := <-traceFreeList: + return tr + default: + return new(trace) + } +} + +// freeTrace adds tr to traceFreeList if there's room. +// This is non-blocking. +func freeTrace(tr *trace) { + if DebugUseAfterFinish { + return // never reuse + } + tr.reset() + select { + case traceFreeList <- tr: + default: + } +} + +func elapsed(d time.Duration) string { + b := []byte(fmt.Sprintf("%.6f", d.Seconds())) + + // For subsecond durations, blank all zeros before decimal point, + // and all zeros between the decimal point and the first non-zero digit. + if d < time.Second { + dot := bytes.IndexByte(b, '.') + for i := 0; i < dot; i++ { + b[i] = ' ' + } + for i := dot + 1; i < len(b); i++ { + if b[i] == '0' { + b[i] = ' ' + } else { + break + } + } + } + + return string(b) +} + +var pageTmplCache *template.Template +var pageTmplOnce sync.Once + +func pageTmpl() *template.Template { + pageTmplOnce.Do(func() { + pageTmplCache = template.Must(template.New("Page").Funcs(template.FuncMap{ + "elapsed": elapsed, + "add": func(a, b int) int { return a + b }, + }).Parse(pageHTML)) + }) + return pageTmplCache +} + +const pageHTML = ` +{{template "Prolog" .}} +{{template "StatusTable" .}} +{{template "Epilog" .}} + +{{define "Prolog"}} +<html> + <head> + <title>/debug/requests</title> + <style type="text/css"> + body { + font-family: sans-serif; + } + table#tr-status td.family { + padding-right: 2em; + } + table#tr-status td.active { + padding-right: 1em; + } + table#tr-status td.latency-first { + padding-left: 1em; + } + table#tr-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> + </head> + <body> + +<h1>/debug/requests</h1> +{{end}} {{/* end of Prolog */}} + +{{define "StatusTable"}} +<table id="tr-status"> + {{range $fam := .Families}} + <tr> + <td class="family">{{$fam}}</td> + + {{$n := index $.ActiveTraceCount $fam}} + <td class="active {{if not $n}}empty{{end}}"> + {{if $n}}<a href="?fam={{$fam}}&b=-1{{if $.Expanded}}&exp=1{{end}}">{{end}} + [{{$n}} active] + {{if $n}}</a>{{end}} + </td> + + {{$f := index $.CompletedTraces $fam}} + {{range $i, $b := $f.Buckets}} + {{$empty := $b.Empty}} + <td {{if $empty}}class="empty"{{end}}> + {{if not $empty}}<a href="?fam={{$fam}}&b={{$i}}{{if $.Expanded}}&exp=1{{end}}">{{end}} + [{{.Cond}}] + {{if not $empty}}</a>{{end}} + </td> + {{end}} + + {{$nb := len $f.Buckets}} + <td class="latency-first"> + <a href="?fam={{$fam}}&b={{$nb}}">[minute]</a> + </td> + <td> + <a href="?fam={{$fam}}&b={{add $nb 1}}">[hour]</a> + </td> + <td> + <a href="?fam={{$fam}}&b={{add $nb 2}}">[total]</a> + </td> + + </tr> + {{end}} +</table> +{{end}} {{/* end of StatusTable */}} + +{{define "Epilog"}} +{{if $.Traces}} +<hr /> +<h3>Family: {{$.Family}}</h3> + +{{if or $.Expanded $.Traced}} + <a href="?fam={{$.Family}}&b={{$.Bucket}}">[Normal/Summary]</a> +{{else}} + [Normal/Summary] +{{end}} + +{{if or (not $.Expanded) $.Traced}} + <a href="?fam={{$.Family}}&b={{$.Bucket}}&exp=1">[Normal/Expanded]</a> +{{else}} + [Normal/Expanded] +{{end}} + +{{if not $.Active}} + {{if or $.Expanded (not $.Traced)}} + <a href="?fam={{$.Family}}&b={{$.Bucket}}&rtraced=1">[Traced/Summary]</a> + {{else}} + [Traced/Summary] + {{end}} + {{if or (not $.Expanded) (not $.Traced)}} + <a href="?fam={{$.Family}}&b={{$.Bucket}}&exp=1&rtraced=1">[Traced/Expanded]</a> + {{else}} + [Traced/Expanded] + {{end}} +{{end}} + +{{if $.Total}} +<p><em>Showing <b>{{len $.Traces}}</b> of <b>{{$.Total}}</b> traces.</em></p> +{{end}} + +<table id="reqs"> + <caption> + {{if $.Active}}Active{{else}}Completed{{end}} Requests + </caption> + <tr><th>When</th><th>Elapsed (s)</th></tr> + {{range $tr := $.Traces}} + <tr class="first"> + <td class="when">{{$tr.When}}</td> + <td class="elapsed">{{$tr.ElapsedTime}}</td> + <td>{{$tr.Title}}</td> + {{/* TODO: include traceID/spanID */}} + </tr> + {{if $.Expanded}} + {{range $tr.Events}} + <tr> + <td class="when">{{.WhenString}}</td> + <td class="elapsed">{{elapsed .Elapsed}}</td> + <td>{{if or $.ShowSensitive (not .Sensitive)}}... {{.What}}{{else}}<em>[redacted]</em>{{end}}</td> + </tr> + {{end}} + {{end}} + {{end}} +</table> +{{end}} {{/* if $.Traces */}} + +{{if $.Histogram}} +<h4>Latency (µs) of {{$.Family}} over {{$.HistogramWindow}}</h4> +{{$.Histogram}} +{{end}} {{/* if $.Histogram */}} + + </body> +</html> +{{end}} {{/* end of Epilog */}} +` |