Headscale: Include last seen in node info

Add debugging API endpoint to run arbitrary headscale command.

Change-Id: I713d55b44d9657971c0ecb8befc8a1408e4b76af
diff --git a/core/headscale/main.go b/core/headscale/main.go
index fb20274..50917d7 100644
--- a/core/headscale/main.go
+++ b/core/headscale/main.go
@@ -115,6 +115,7 @@
 	r.HandleFunc("/user/{user}/node", s.getUserNodes).Methods(http.MethodGet)
 	r.HandleFunc("/user", s.createUser).Methods(http.MethodPost)
 	r.HandleFunc("/routes/{id}/enable", s.enableRoute).Methods(http.MethodPost)
+	r.HandleFunc("/cmd", s.runCmd).Methods(http.MethodPost)
 	go func() {
 		rand.Seed(uint64(time.Now().UnixNano()))
 		s.syncUsers()
@@ -127,6 +128,24 @@
 	return http.ListenAndServe(fmt.Sprintf(":%d", s.port), r)
 }
 
+type cmdReq struct {
+	Cmd string `json:"cmd"`
+}
+
+func (s *server) runCmd(w http.ResponseWriter, r *http.Request) {
+	var req cmdReq
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	if out, err := s.client.run(strings.Split(req.Cmd, " ")...); err != nil && !errors.Is(err, ErrorAlreadyExists) {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	} else {
+		fmt.Fprint(w, out)
+	}
+}
+
 type createUserReq struct {
 	Name string `json:"name"`
 }