Function SnapshotHandler

stack/webstack/webstack.go:46–94

SnapshotHandler implements http.HandlerFunc to returns a panicparse HTML format for a snapshot of the current goroutines. For best results, compile the executable with optimization (-N) and inlining (-l) disabled with -gcflags '-N -l'. Arguments are passed as form values. If you want to change the

(w http.ResponseWriter, req *http.Request)

// similarity: (default: "anypointer") Can be one of stack.Similarity value in
// lowercase: "exactflags", "exactlines", "anypointer" or "anyvalue".
func SnapshotHandler(w http.ResponseWriter, req *http.Request) {
	if req.Method != "GET" {
		http.Error(w, "invalid method", http.StatusMethodNotAllowed)
		return
	}

	maxmem := 64 << 20
	if s := req.FormValue("maxmem"); s != "" {
		var err error
		if maxmem, err = strconv.Atoi(s); err != nil {
			http.Error(w, "invalid maxmem value", http.StatusBadRequest)
			return
		}
	}
	opts := stack.DefaultOpts()
	if s := req.FormValue("augment"); s != "" {
		v, err := strconv.Atoi(s)
		if err != nil || v < 0 || v > 1 {
			http.Error(w, "invalid augment value", http.StatusBadRequest)
			return
		}
		if v == 0 {
			opts.AnalyzeSources = false
		}
	}
	c, err := snapshot(maxmem, opts)
	if err != nil {
		http.Error(w, "failed to process the snapshot, try a larger maxmem value", http.StatusInternalServerError)
		return
	}

	var s stack.Similarity
	switch req.FormValue("similarity") {
	case "exactflags":
		s = stack.ExactFlags
	case "exactlines":
		s = stack.ExactLines
	case "anypointer", "":
		s = stack.AnyPointer
	case "anyvalue":
		s = stack.AnyValue
	default:
		http.Error(w, "invalid similarity value", http.StatusBadRequest)
		return
	}

	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	_ = c.Aggregate(s).ToHTML(w, "")
}

// snapshot returns a Context based on the snapshot of the stacks of the
// current process.