2022-12-08 13:05:19 -03:00

91 lines
2.8 KiB
Go

// Copyright (c) 2020 Gitpod GmbH. All rights reserved.
// Licensed under the GNU Affero General Public License (AGPL).
// See License.AGPL.txt in the project root for license information.
package pprof
import (
"math/rand"
"net/http"
"net/http/pprof"
"runtime"
"strconv"
"strings"
"github.com/gitpod-io/gitpod/common-go/log"
)
// http handler path which MUST be used as a prefix to route pprof endpoint
// since it is hardcoded inside pprof
const Path = "/debug/pprof/"
// Serve starts a new HTTP server serving pprof endpoints on the given addr
func Serve(addr string) {
mux := Handler()
log.WithField("addr", addr).Info("serving pprof service")
err := http.ListenAndServe(addr, mux)
if err != nil {
log.WithField("addr", addr).WithError(err).Warn("cannot serve pprof service")
}
}
// Handler produces the pprof endpoint handler
func Handler() *http.ServeMux {
mux := http.NewServeMux()
mux.HandleFunc(Path, index)
mux.HandleFunc(Path+"cmdline", pprof.Cmdline)
mux.HandleFunc(Path+"profile", pprof.Profile)
mux.HandleFunc(Path+"symbol", pprof.Symbol)
mux.HandleFunc(Path+"trace", pprof.Trace)
mux.HandleFunc("/debug/logging", log.LevelHandler)
return mux
}
func index(w http.ResponseWriter, r *http.Request) {
if strings.HasPrefix(r.URL.Path, Path) {
// according to Ian Lance Taylor it's ok to turn on mutex and block profiling
// when asking for the actual profile [1]. This handler implements this idea, as
// discussed in [2]
//
// [1] https://groups.google.com/forum/#!topic/golang-nuts/qiHa97XzeCw
// [2] https://github.com/golang/go/issues/23401
var (
name = strings.TrimPrefix(r.URL.Path, Path)
seconds, serr = strconv.ParseInt(r.URL.Query().Get("seconds"), 10, 64)
)
if name == "mutex" {
frac, ferr := strconv.ParseInt(r.URL.Query().Get("frac"), 10, 64)
if serr == nil && ferr == nil && seconds > 0 && frac > 0 {
//nolint:gosec
id := rand.Uint32()
log.WithField("id", id).WithField("frac", frac).WithField("seconds", seconds).Debug("enabled mutex profiling")
runtime.SetMutexProfileFraction(int(frac))
defer func() {
runtime.SetMutexProfileFraction(0)
log.WithField("id", id).WithField("frac", frac).WithField("seconds", seconds).Debug("disabled mutex profiling")
}()
}
} else if name == "block" {
rate, rerr := strconv.ParseInt(r.URL.Query().Get("rate"), 10, 64)
if rerr == nil && rate > 0 && serr == nil && seconds > 0 {
//nolint:gosec
id := rand.Uint32()
log.WithField("id", id).WithField("rate", rate).WithField("seconds", seconds).Debug("enabled mutex block sampling")
runtime.SetBlockProfileRate(int(rate))
defer func() {
runtime.SetBlockProfileRate(0)
log.WithField("id", id).WithField("rate", rate).WithField("seconds", seconds).Debug("disabled mutex block sampling")
}()
}
}
}
pprof.Index(w, r)
}