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1131 lines
28 KiB
Go
1131 lines
28 KiB
Go
2 years ago
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// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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/*
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Package trace implements tracing of requests and long-lived objects.
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It exports HTTP interfaces on /debug/requests and /debug/events.
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A trace.Trace provides tracing for short-lived objects, usually requests.
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A request handler might be implemented like this:
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func fooHandler(w http.ResponseWriter, req *http.Request) {
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tr := trace.New("mypkg.Foo", req.URL.Path)
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defer tr.Finish()
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...
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tr.LazyPrintf("some event %q happened", str)
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...
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if err := somethingImportant(); err != nil {
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tr.LazyPrintf("somethingImportant failed: %v", err)
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tr.SetError()
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}
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}
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The /debug/requests HTTP endpoint organizes the traces by family,
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errors, and duration. It also provides histogram of request duration
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for each family.
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A trace.EventLog provides tracing for long-lived objects, such as RPC
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connections.
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// A Fetcher fetches URL paths for a single domain.
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type Fetcher struct {
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domain string
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events trace.EventLog
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}
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func NewFetcher(domain string) *Fetcher {
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return &Fetcher{
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domain,
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trace.NewEventLog("mypkg.Fetcher", domain),
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}
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}
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func (f *Fetcher) Fetch(path string) (string, error) {
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resp, err := http.Get("http://" + f.domain + "/" + path)
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if err != nil {
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f.events.Errorf("Get(%q) = %v", path, err)
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return "", err
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}
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f.events.Printf("Get(%q) = %s", path, resp.Status)
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...
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}
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func (f *Fetcher) Close() error {
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f.events.Finish()
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return nil
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}
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The /debug/events HTTP endpoint organizes the event logs by family and
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by time since the last error. The expanded view displays recent log
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entries and the log's call stack.
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*/
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package trace // import "golang.org/x/net/trace"
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import (
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"bytes"
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"context"
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"fmt"
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"html/template"
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"io"
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"log"
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"net"
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"net/http"
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"net/url"
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"runtime"
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"sort"
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"strconv"
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"sync"
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"sync/atomic"
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"time"
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"golang.org/x/net/internal/timeseries"
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)
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// DebugUseAfterFinish controls whether to debug uses of Trace values after finishing.
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// FOR DEBUGGING ONLY. This will slow down the program.
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var DebugUseAfterFinish = false
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// HTTP ServeMux paths.
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const (
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debugRequestsPath = "/debug/requests"
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debugEventsPath = "/debug/events"
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)
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// AuthRequest determines whether a specific request is permitted to load the
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// /debug/requests or /debug/events pages.
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//
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// It returns two bools; the first indicates whether the page may be viewed at all,
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// and the second indicates whether sensitive events will be shown.
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//
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// AuthRequest may be replaced by a program to customize its authorization requirements.
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//
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// The default AuthRequest function returns (true, true) if and only if the request
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// comes from localhost/127.0.0.1/[::1].
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var AuthRequest = func(req *http.Request) (any, sensitive bool) {
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// RemoteAddr is commonly in the form "IP" or "IP:port".
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// If it is in the form "IP:port", split off the port.
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host, _, err := net.SplitHostPort(req.RemoteAddr)
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if err != nil {
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host = req.RemoteAddr
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}
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switch host {
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case "localhost", "127.0.0.1", "::1":
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return true, true
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default:
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return false, false
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}
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}
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func init() {
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_, pat := http.DefaultServeMux.Handler(&http.Request{URL: &url.URL{Path: debugRequestsPath}})
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if pat == debugRequestsPath {
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panic("/debug/requests is already registered. You may have two independent copies of " +
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"golang.org/x/net/trace in your binary, trying to maintain separate state. This may " +
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"involve a vendored copy of golang.org/x/net/trace.")
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}
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// TODO(jbd): Serve Traces from /debug/traces in the future?
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// There is no requirement for a request to be present to have traces.
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http.HandleFunc(debugRequestsPath, Traces)
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http.HandleFunc(debugEventsPath, Events)
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}
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// NewContext returns a copy of the parent context
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// and associates it with a Trace.
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func NewContext(ctx context.Context, tr Trace) context.Context {
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return context.WithValue(ctx, contextKey, tr)
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}
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// FromContext returns the Trace bound to the context, if any.
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func FromContext(ctx context.Context) (tr Trace, ok bool) {
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tr, ok = ctx.Value(contextKey).(Trace)
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return
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}
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// Traces responds with traces from the program.
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// The package initialization registers it in http.DefaultServeMux
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// at /debug/requests.
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//
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// It performs authorization by running AuthRequest.
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func Traces(w http.ResponseWriter, req *http.Request) {
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any, sensitive := AuthRequest(req)
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if !any {
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http.Error(w, "not allowed", http.StatusUnauthorized)
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return
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}
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w.Header().Set("Content-Type", "text/html; charset=utf-8")
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Render(w, req, sensitive)
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}
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// Events responds with a page of events collected by EventLogs.
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// The package initialization registers it in http.DefaultServeMux
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// at /debug/events.
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//
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// It performs authorization by running AuthRequest.
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func Events(w http.ResponseWriter, req *http.Request) {
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any, sensitive := AuthRequest(req)
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if !any {
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http.Error(w, "not allowed", http.StatusUnauthorized)
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return
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}
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w.Header().Set("Content-Type", "text/html; charset=utf-8")
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RenderEvents(w, req, sensitive)
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}
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// Render renders the HTML page typically served at /debug/requests.
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// It does not do any auth checking. The request may be nil.
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//
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// Most users will use the Traces handler.
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func Render(w io.Writer, req *http.Request, sensitive bool) {
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data := &struct {
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Families []string
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ActiveTraceCount map[string]int
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CompletedTraces map[string]*family
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// Set when a bucket has been selected.
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Traces traceList
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Family string
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Bucket int
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Expanded bool
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Traced bool
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Active bool
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ShowSensitive bool // whether to show sensitive events
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|
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Histogram template.HTML
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HistogramWindow string // e.g. "last minute", "last hour", "all time"
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|
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// If non-zero, the set of traces is a partial set,
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// and this is the total number.
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Total int
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}{
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CompletedTraces: completedTraces,
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}
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data.ShowSensitive = sensitive
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if req != nil {
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// Allow show_sensitive=0 to force hiding of sensitive data for testing.
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// This only goes one way; you can't use show_sensitive=1 to see things.
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if req.FormValue("show_sensitive") == "0" {
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data.ShowSensitive = false
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}
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if exp, err := strconv.ParseBool(req.FormValue("exp")); err == nil {
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data.Expanded = exp
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}
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if exp, err := strconv.ParseBool(req.FormValue("rtraced")); err == nil {
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data.Traced = exp
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}
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}
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completedMu.RLock()
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data.Families = make([]string, 0, len(completedTraces))
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for fam := range completedTraces {
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data.Families = append(data.Families, fam)
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}
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completedMu.RUnlock()
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sort.Strings(data.Families)
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// We are careful here to minimize the time spent locking activeMu,
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// since that lock is required every time an RPC starts and finishes.
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data.ActiveTraceCount = make(map[string]int, len(data.Families))
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activeMu.RLock()
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for fam, s := range activeTraces {
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data.ActiveTraceCount[fam] = s.Len()
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}
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activeMu.RUnlock()
|
||
|
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var ok bool
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||
|
data.Family, data.Bucket, ok = parseArgs(req)
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||
|
switch {
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||
|
case !ok:
|
||
|
// No-op
|
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|
case data.Bucket == -1:
|
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|
data.Active = true
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n := data.ActiveTraceCount[data.Family]
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data.Traces = getActiveTraces(data.Family)
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if len(data.Traces) < n {
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data.Total = n
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}
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case data.Bucket < bucketsPerFamily:
|
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if b := lookupBucket(data.Family, data.Bucket); b != nil {
|
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|
data.Traces = b.Copy(data.Traced)
|
||
|
}
|
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|
default:
|
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if f := getFamily(data.Family, false); f != nil {
|
||
|
var obs timeseries.Observable
|
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|
f.LatencyMu.RLock()
|
||
|
switch o := data.Bucket - bucketsPerFamily; o {
|
||
|
case 0:
|
||
|
obs = f.Latency.Minute()
|
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|
data.HistogramWindow = "last minute"
|
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|
case 1:
|
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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.Now().Sub(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 */}}
|
||
|
`
|