From b1bc08e2686e2aa73aaf2108fdc50d9e700def38 Mon Sep 17 00:00:00 2001
From: Jerry Jacobs <xor-gate@users.noreply.github.com>
Date: Tue, 7 Aug 2018 20:49:18 +0200
Subject: [PATCH] cmd/serve: pprof cpu and memory profile dumps to disk (#4560)

---
 cmd/serv.go                | 16 +++++++++++++++
 custom/conf/app.ini.sample |  8 +++++++-
 modules/pprof/pprof.go     | 42 ++++++++++++++++++++++++++++++++++++++
 modules/setting/setting.go |  5 +++++
 4 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 modules/pprof/pprof.go

diff --git a/cmd/serv.go b/cmd/serv.go
index 990355be98..b532b95494 100644
--- a/cmd/serv.go
+++ b/cmd/serv.go
@@ -16,6 +16,7 @@ import (
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/pprof"
 	"code.gitea.io/gitea/modules/private"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/util"
@@ -42,6 +43,9 @@ var CmdServ = cli.Command{
 			Value: "custom/conf/app.ini",
 			Usage: "Custom configuration file path",
 		},
+		cli.BoolFlag{
+			Name: "enable-pprof",
+		},
 	},
 }
 
@@ -143,6 +147,18 @@ func runServ(c *cli.Context) error {
 	username := strings.ToLower(rr[0])
 	reponame := strings.ToLower(strings.TrimSuffix(rr[1], ".git"))
 
+	if setting.EnablePprof || c.Bool("enable-pprof") {
+		if err := os.MkdirAll(setting.PprofDataPath, os.ModePerm); err != nil {
+			fail("Error while trying to create PPROF_DATA_PATH", "Error while trying to create PPROF_DATA_PATH: %v", err)
+		}
+
+		stopCPUProfiler := pprof.DumpCPUProfileForUsername(setting.PprofDataPath, username)
+		defer func() {
+			stopCPUProfiler()
+			pprof.DumpMemProfileForUsername(setting.PprofDataPath, username)
+		}()
+	}
+
 	isWiki := false
 	unitType := models.UnitTypeCode
 	if strings.HasSuffix(reponame, ".wiki") {
diff --git a/custom/conf/app.ini.sample b/custom/conf/app.ini.sample
index a705981be0..682a03b8bf 100644
--- a/custom/conf/app.ini.sample
+++ b/custom/conf/app.ini.sample
@@ -187,6 +187,12 @@ STATIC_ROOT_PATH =
 APP_DATA_PATH = data
 ; Application level GZIP support
 ENABLE_GZIP = false
+; Application profiling (memory and cpu)
+; For "web" command it listens on localhost:6060
+; For "serve" command it dumps to disk at PPROF_DATA_PATH as (cpuprofile|memprofile)_<username>_<temporary id>
+ENABLE_PPROF = false
+; PPROF_DATA_PATH, use an absolute path when you start gitea as service
+PPROF_DATA_PATH = data/tmp/pprof
 ; Landing page, can be "home", "explore", or "organizations"
 LANDING_PAGE = home
 ; Enables git-lfs support. true or false, default is false.
@@ -215,7 +221,7 @@ USER = root
 PASSWD =
 ; For "postgres" only, either "disable", "require" or "verify-full"
 SSL_MODE = disable
-; For "sqlite3" and "tidb", use absolute path when you start gitea as service
+; For "sqlite3" and "tidb", use an absolute path when you start gitea as service
 PATH = data/gitea.db
 ; For "sqlite3" only. Query timeout
 SQLITE_TIMEOUT = 500
diff --git a/modules/pprof/pprof.go b/modules/pprof/pprof.go
new file mode 100644
index 0000000000..7f4fc653f3
--- /dev/null
+++ b/modules/pprof/pprof.go
@@ -0,0 +1,42 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package pprof
+
+import (
+	"fmt"
+	"io/ioutil"
+	"runtime"
+	"runtime/pprof"
+
+	"code.gitea.io/gitea/modules/log"
+)
+
+// DumpMemProfileForUsername dumps a memory profile at pprofDataPath as memprofile_<username>_<temporary id>
+func DumpMemProfileForUsername(pprofDataPath, username string) {
+	f, err := ioutil.TempFile(pprofDataPath, fmt.Sprintf("memprofile_%s_", username))
+	if err != nil {
+		log.GitLogger.Fatal(4, "Could not create memory profile: %v", err)
+	}
+	defer f.Close()
+	runtime.GC() // get up-to-date statistics
+	if err := pprof.WriteHeapProfile(f); err != nil {
+		log.GitLogger.Fatal(4, "Could not write memory profile: %v", err)
+	}
+}
+
+// DumpCPUProfileForUsername dumps a CPU profile at pprofDataPath as cpuprofile_<username>_<temporary id>
+//  it returns the stop function which stops, writes and closes the CPU profile file
+func DumpCPUProfileForUsername(pprofDataPath, username string) func() {
+	f, err := ioutil.TempFile(pprofDataPath, fmt.Sprintf("cpuprofile_%s_", username))
+	if err != nil {
+		log.GitLogger.Fatal(4, "Could not create cpu profile: %v", err)
+	}
+
+	pprof.StartCPUProfile(f)
+	return func() {
+		pprof.StopCPUProfile()
+		f.Close()
+	}
+}
diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index 1dd45f0f77..4a231c1a52 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -111,6 +111,7 @@ var (
 	LandingPageURL       LandingPage
 	UnixSocketPermission uint32
 	EnablePprof          bool
+	PprofDataPath        string
 
 	SSH = struct {
 		Disabled             bool           `ini:"DISABLE_SSH"`
@@ -775,6 +776,10 @@ func NewContext() {
 	AppDataPath = sec.Key("APP_DATA_PATH").MustString(path.Join(AppWorkPath, "data"))
 	EnableGzip = sec.Key("ENABLE_GZIP").MustBool()
 	EnablePprof = sec.Key("ENABLE_PPROF").MustBool(false)
+	PprofDataPath = sec.Key("PPROF_DATA_PATH").MustString(path.Join(AppWorkPath, "data/tmp/pprof"))
+	if !filepath.IsAbs(PprofDataPath) {
+		PprofDataPath = filepath.Join(AppWorkPath, PprofDataPath)
+	}
 
 	switch sec.Key("LANDING_PAGE").MustString("home") {
 	case "explore":