1 files changed, 209 insertions, 0 deletions
diff --git a/src/net/http/pprof/pprof.go b/src/net/http/pprof/pprof.go
new file mode 100644
index 000000000..a23f1bc4b
--- /dev/null
+++ b/src/net/http/pprof/pprof.go
@@ -0,0 +1,209 @@
+// 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 _ "net/http/pprof"
+//
+// If your application is not already running an http server, you
+// need to start one.  Add "net/http" and "log" to your imports and
+// the following code to your main function:
+//
+// 	go func() {
+// 		log.Println(http.ListenAndServe("localhost:6060", nil))
+// 	}()
+//
+// Then use the pprof tool to look at the heap profile:
+//
+//	go tool pprof http://localhost:6060/debug/pprof/heap
+//
+// Or to look at a 30-second CPU profile:
+//
+//	go tool pprof http://localhost:6060/debug/pprof/profile
+//
+// Or to look at the goroutine blocking profile:
+//
+//	go tool pprof http://localhost:6060/debug/pprof/block
+//
+// To view all available profiles, open http://localhost:6060/debug/pprof/
+// in your browser.
+//
+// For a study of the facility in action, visit
+//
+//	http://blog.golang.org/2011/06/profiling-go-programs.html
+//
+package pprof
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"html/template"
+	"io"
+	"log"
+	"net/http"
+	"os"
+	"runtime"
+	"runtime/pprof"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func init() {
+	http.Handle("/debug/pprof/", http.HandlerFunc(Index))
+	http.Handle("/debug/pprof/cmdline", http.HandlerFunc(Cmdline))
+	http.Handle("/debug/pprof/profile", http.HandlerFunc(Profile))
+	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(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	fmt.Fprintf(w, strings.Join(os.Args, "\x00"))
+}
+
+// Profile responds with the pprof-formatted cpu profile.
+// The package initialization registers it as /debug/pprof/profile.
+func Profile(w http.ResponseWriter, r *http.Request) {
+	sec, _ := strconv.ParseInt(r.FormValue("seconds"), 10, 64)
+	if sec == 0 {
+		sec = 30
+	}
+
+	// Set Content Type assuming StartCPUProfile will work,
+	// because if it does it starts writing.
+	w.Header().Set("Content-Type", "application/octet-stream")
+	if err := pprof.StartCPUProfile(w); err != nil {
+		// StartCPUProfile failed, so no writes yet.
+		// Can change header back to text content
+		// and send error code.
+		w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+		w.WriteHeader(http.StatusInternalServerError)
+		fmt.Fprintf(w, "Could not enable CPU profiling: %s\n", err)
+		return
+	}
+	time.Sleep(time.Duration(sec) * time.Second)
+	pprof.StopCPUProfile()
+}
+
+// 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(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+
+	// We have to read the whole POST body before
+	// writing any output.  Buffer the output here.
+	var buf bytes.Buffer
+
+	// 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(&buf, "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 {
+		word, err := b.ReadSlice('+')
+		if err == nil {
+			word = word[0 : len(word)-1] // trim +
+		}
+		pc, _ := strconv.ParseUint(string(word), 0, 64)
+		if pc != 0 {
+			f := runtime.FuncForPC(uintptr(pc))
+			if f != nil {
+				fmt.Fprintf(&buf, "%#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 {
+			if err != io.EOF {
+				fmt.Fprintf(&buf, "reading request: %v\n", err)
+			}
+			break
+		}
+	}
+
+	w.Write(buf.Bytes())
+}
+
+// Handler returns an HTTP handler that serves the named profile.
+func Handler(name string) http.Handler {
+	return handler(name)
+}
+
+type handler string
+
+func (name handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	debug, _ := strconv.Atoi(r.FormValue("debug"))
+	p := pprof.Lookup(string(name))
+	if p == nil {
+		w.WriteHeader(404)
+		fmt.Fprintf(w, "Unknown profile: %s\n", name)
+		return
+	}
+	gc, _ := strconv.Atoi(r.FormValue("gc"))
+	if name == "heap" && gc > 0 {
+		runtime.GC()
+	}
+	p.WriteTo(w, debug)
+	return
+}
+
+// Index responds with the pprof-formatted profile named by the request.
+// For example, "/debug/pprof/heap" serves the "heap" profile.
+// Index responds to a request for "/debug/pprof/" with an HTML page
+// listing the available profiles.
+func Index(w http.ResponseWriter, r *http.Request) {
+	if strings.HasPrefix(r.URL.Path, "/debug/pprof/") {
+		name := strings.TrimPrefix(r.URL.Path, "/debug/pprof/")
+		if name != "" {
+			handler(name).ServeHTTP(w, r)
+			return
+		}
+	}
+
+	profiles := pprof.Profiles()
+	if err := indexTmpl.Execute(w, profiles); err != nil {
+		log.Print(err)
+	}
+}
+
+var indexTmpl = template.Must(template.New("index").Parse(`<html>
+<head>
+<title>/debug/pprof/</title>
+</head>
+/debug/pprof/<br>
+<br>
+<body>
+profiles:<br>
+<table>
+{{range .}}
+<tr><td align=right>{{.Count}}<td><a href="/debug/pprof/{{.Name}}?debug=1">{{.Name}}</a>
+{{end}}
+</table>
+<br>
+<a href="/debug/pprof/goroutine?debug=2">full goroutine stack dump</a><br>
+</body>
+</html>
+`))