diff options
Diffstat (limited to 'vendor/golang.org/x/net/trace/events.go')
| -rw-r--r-- | vendor/golang.org/x/net/trace/events.go | 524 |
1 files changed, 524 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..e66c7e3 --- /dev/null +++ b/vendor/golang.org/x/net/trace/events.go @@ -0,0 +1,524 @@ +// 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" +) + +var eventsTmpl = template.Must(template.New("events").Funcs(template.FuncMap{ + "elapsed": elapsed, + "trimSpace": strings.TrimSpace, +}).Parse(eventsHTML)) + +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; see AuthRequest for the default auth check +// used by the handler registered on http.DefaultServeMux. +// req may be nil. +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: + } +} + +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> +` |