// 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()
}
// before runs before all testing.
func before() {
if *memProfileRate > 0 {
runtime.MemProfileRate = *memProfileRate
}
if *cpuProfile != "" {
f, err := os.Create(toOutputDir(*cpuProfile))
if err != nil {
fmt.Fprintf(os.Stderr, "testing: %s", err)
return
}
if err := pprof.StartCPUProfile(f); err != nil {
fmt.Fprintf(os.Stderr, "testing: can't start cpu profile: %s", err)
f.Close()
return
}
// Could save f so after can call f.Close; not worth the effort.
}
if *trace != "" {
f, err := os.Create(toOutputDir(*trace))
if err != nil {
fmt.Fprintf(os.Stderr, "testing: %s", err)
return
}
if err := pprof.StartTrace(f); err != nil {
fmt.Fprintf(os.Stderr, "testing: can't start tracing: %s", err)
f.Close()
return
}
// Could save f so after can call f.Close; not worth the effort.
}
if *blockProfile != "" && *blockProfileRate >= 0 {
runtime.SetBlockProfileRate(*blockProfileRate)
}
if *coverProfile != "" && cover.Mode == "" {
fmt.Fprintf(os.Stderr, "testing: cannot use -test.coverprofile because test binary was not built with coverage enabled\n")
os.Exit(2)
}
}