net/http/pprof: add tracing support
net/http/pprof part of tracing functionality:
https://docs.google.com/document/u/1/d/1FP5apqzBgr7ahCCgFO-yoVhk4YZrNIDNf9RybngBc14/pub
Full change:
https://codereview.appspot.com/146920043
Change-Id: I9092028fcbd5e8f97a56f2c155889ccdfb494afb
Reviewed-on: https://go-review.googlesource.com/1453
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/src/net/http/pprof/pprof.go b/src/net/http/pprof/pprof.go
index a23f1bc..f5a352d 100644
--- a/src/net/http/pprof/pprof.go
+++ b/src/net/http/pprof/pprof.go
@@ -34,6 +34,10 @@
//
// go tool pprof http://localhost:6060/debug/pprof/block
//
+// Or to collect a 5-second execution trace:
+//
+// wget http://localhost:6060/debug/pprof/trace?seconds=5
+//
// To view all available profiles, open http://localhost:6060/debug/pprof/
// in your browser.
//
@@ -64,6 +68,7 @@
http.Handle("/debug/pprof/cmdline", http.HandlerFunc(Cmdline))
http.Handle("/debug/pprof/profile", http.HandlerFunc(Profile))
http.Handle("/debug/pprof/symbol", http.HandlerFunc(Symbol))
+ http.Handle("/debug/pprof/trace", http.HandlerFunc(Trace))
}
// Cmdline responds with the running program's
@@ -98,6 +103,30 @@
pprof.StopCPUProfile()
}
+// Trace responds with the execution trace in binary form.
+// Tracing lasts for duration specified in seconds GET parameter, or for 1 second if not specified.
+// The package initialization registers it as /debug/pprof/trace.
+func Trace(w http.ResponseWriter, r *http.Request) {
+ sec, _ := strconv.ParseInt(r.FormValue("seconds"), 10, 64)
+ if sec == 0 {
+ sec = 1
+ }
+
+ // Set Content Type assuming StartTrace will work,
+ // because if it does it starts writing.
+ w.Header().Set("Content-Type", "application/octet-stream")
+ if err := pprof.StartTrace(w); err != nil {
+ // StartTrace 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 tracing: %s\n", err)
+ return
+ }
+ time.Sleep(time.Duration(sec) * time.Second)
+ pprof.StopTrace()
+}
+
// 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.
