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// Copyright 2010 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 pprof serves via its HTTP server runtime profiling data
// in the format expected by the pprof visualization tool.
// For more information about pprof, see
// http://code.google.com/p/google-perftools/.
//
// The package is typically only imported for the side effect of
// registering its HTTP handlers.
// The handled paths all begin with /debug/pprof/.
//
// To use pprof, link this package into your program:
// import _ "http/pprof"
//
// Then use the pprof tool to look at the heap profile:
//
// pprof http://localhost:6060/debug/pprof/heap
//
package pprof
import (
"bufio"
"fmt"
"http"
"os"
"runtime"
"runtime/pprof"
"strconv"
"strings"
)
func init() {
http.Handle("/debug/pprof/cmdline", http.HandlerFunc(Cmdline))
http.Handle("/debug/pprof/heap", http.HandlerFunc(Heap))
http.Handle("/debug/pprof/symbol", http.HandlerFunc(Symbol))
}
// Cmdline responds with the running program's
// command line, with arguments separated by NUL bytes.
// The package initialization registers it as /debug/pprof/cmdline.
func Cmdline(c *http.Conn, r *http.Request) {
c.SetHeader("content-type", "text/plain; charset=utf-8")
fmt.Fprintf(c, strings.Join(os.Args, "\x00"))
}
// Heap responds with the pprof-formatted heap profile.
// The package initialization registers it as /debug/pprof/heap.
func Heap(c *http.Conn, r *http.Request) {
c.SetHeader("content-type", "text/plain; charset=utf-8")
pprof.WriteHeapProfile(c)
}
// Symbol looks up the program counters listed in the request,
// responding with a table mapping program counters to function names.
// The package initialization registers it as /debug/pprof/symbol.
func Symbol(c *http.Conn, r *http.Request) {
c.SetHeader("content-type", "text/plain; charset=utf-8")
// We don't know how many symbols we have, but we
// do have symbol information. Pprof only cares whether
// this number is 0 (no symbols available) or > 0.
fmt.Fprintf(c, "num_symbols: 1\n")
var b *bufio.Reader
if r.Method == "POST" {
b = bufio.NewReader(r.Body)
} else {
b = bufio.NewReader(strings.NewReader(r.URL.RawQuery))
}
for {
w, err := b.ReadSlice('+')
if err == nil {
w = w[0 : len(w)-1] // trim +
}
pc, _ := strconv.Btoui64(string(w), 0)
if pc != 0 {
f := runtime.FuncForPC(uintptr(pc))
if f != nil {
fmt.Fprintf(c, "%#x %s\n", pc, f.Name())
}
}
// Wait until here to check for err; the last
// symbol will have an err because it doesn't end in +.
if err != nil {
break
}
}
}