Support pprof information over HTTP

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 3.3.0 (unreleased)
+- [PR #148](https://github.com/rqlite/rqlite/pull/148): Support pprof information over HTTP.
+
 ## 3.2.1 (May 22nd 2016)
 - [PR #143](https://github.com/rqlite/rqlite/pull/143): Use DELETE as HTTP method to remove nodes.
 

cmd/rqlited/main.go

@@ -73,6 +73,7 @@ var raftAdv string
 var joinAddr string
 var noVerify bool
 var expvar bool
+var pprofEnabled bool
 var dsn string
 var onDisk bool
 var noVerifySelect bool
@@ -92,6 +93,7 @@ func init() {
 	flag.StringVar(&joinAddr, "join", "", "protocol://host:port of leader to join")
 	flag.BoolVar(&noVerify, "noverify", false, "Skip verification of any HTTPS cert when joining")
 	flag.BoolVar(&expvar, "expvar", true, "Serve expvar data on HTTP server")
+	flag.BoolVar(&pprofEnabled, "pprof", true, "Serve pprof data on HTTP server")
 	flag.StringVar(&dsn, "dsn", "", `SQLite DSN parameters. E.g. "cache=shared&mode=memory"`)
 	flag.BoolVar(&onDisk, "ondisk", false, "Use an on-disk SQLite database")
 	flag.BoolVar(&noVerifySelect, "nosel", false, "Don't verify that all queries begin with SELECT")
@@ -237,6 +239,7 @@ func main() {
 	s.KeyFile = x509Key
 	s.NoVerifySelect = noVerifySelect
 	s.Expvar = expvar
+	s.Pprof = pprofEnabled
 	s.BuildInfo = map[string]interface{}{
 		"commit":     commit,
 		"branch":     branch,

doc/DIAGNOSTICS.md

@@ -8,8 +8,17 @@ curl localhost:4001/status?pretty
 The use of the URL param `pretty` is optional, and results in pretty-printed JSON responses.
 
 ## expvar support
-rqlite also exports [expvar](http://godoc.org/pkg/expvar/) information. The standard expvar information, as well as some custom information, is exposed. This data can be retrieved like so:
+rqlite also exports [expvar](http://godoc.org/pkg/expvar/) information. The standard expvar information, as well as some custom information, is exposed. This data can be retrieved like so (assuming the node is started in its default configuration):
 
 ```bash
 curl localhost:4001/debug/vars
 ```
+
+## pprof support
+pprof information is available by default and can be retrieved as follows:
+
+```bash
+curl localhost:4001/debug/pprof/cmdline
+curl localhost:4001/debug/pprof/profile
+curl localhost:4001/debug/pprof/symbol
+```

http/service.go

@@ -12,6 +12,7 @@ import (
 	"log"
 	"net"
 	"net/http"
+	"net/http/pprof"
 	"os"
 	"runtime"
 	"strings"
@@ -128,6 +129,7 @@ type Service struct {
 	credentialStore CredentialStore
 
 	Expvar bool
+	Pprof  bool
 
 	BuildInfo map[string]interface{}
 
@@ -217,6 +219,8 @@ func (s *Service) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		s.handleStatus(w, r)
 	case r.URL.Path == "/debug/vars" && s.Expvar:
 		serveExpvar(w, r)
+	case strings.HasPrefix(r.URL.Path, "/debug/pprof") && s.Pprof:
+		servePprof(w, r)
 	default:
 		w.WriteHeader(http.StatusNotFound)
 	}
@@ -599,6 +603,20 @@ func serveExpvar(w http.ResponseWriter, r *http.Request) {
 	fmt.Fprintf(w, "\n}\n")
 }
 
+// servePprof serves pprof information over HTTP.
+func servePprof(w http.ResponseWriter, r *http.Request) {
+	switch r.URL.Path {
+	case "/debug/pprof/cmdline":
+		pprof.Cmdline(w, r)
+	case "/debug/pprof/profile":
+		pprof.Profile(w, r)
+	case "/debug/pprof/symbol":
+		pprof.Symbol(w, r)
+	default:
+		pprof.Index(w, r)
+	}
+}
+
 func writeResponse(w http.ResponseWriter, r *http.Request, j *Response) {
 	var b []byte
 	var err error