Allow user to logout from Livebook app (#2961)

lib/livebook_web/helpers/session_helpers.ex

@@ -274,4 +274,32 @@ defmodule LivebookWeb.SessionHelpers do
       Livebook.Session.register_file(session_pid, path, key)
     end
   end
+
+  @logout_topic "logout"
+
+  @doc """
+  Subscribes to #{@logout_topic} topic.
+  """
+  @spec subscribe_to_logout() :: :ok | {:error, term()}
+  def subscribe_to_logout do
+    Phoenix.PubSub.subscribe(Livebook.PubSub, @logout_topic)
+  end
+
+  @doc """
+  Shows the confirmation modal to logout user from Livebook.
+  """
+  @spec confirm_logout(Socket.t()) :: Socket.t()
+  def confirm_logout(socket) do
+    on_confirm = fn socket ->
+      Phoenix.PubSub.broadcast(Livebook.PubSub, @logout_topic, :logout)
+      put_flash(socket, :info, "Livebook is logging out. You will be redirected soon.")
+    end
+
+    confirm(socket, on_confirm,
+      title: "Log out",
+      description: "Are you sure you want to log out Livebook now?",
+      confirm_text: "Log out",
+      confirm_icon: "logout-box-line"
+    )
+  end
 end

lib/livebook_web/live/app_session_live.ex

@@ -140,6 +140,12 @@ defmodule LivebookWeb.AppSessionLive do
                 <span>Debug</span>
               </.link>
             </.menu_item>
+            <.menu_item :if={Livebook.Config.logout_enabled?() and @current_user.email != nil}>
+              <button phx-click="logout" role="menuitem">
+                <.remix_icon icon="logout-box-line" />
+                <span>Logout</span>
+              </button>
+            </.menu_item>
           </.menu>
         </div>
         <div data-el-js-view-iframes phx-update="ignore" id="js-view-iframes"></div>

lib/livebook_web/live/hooks/app_auth_hook.ex

@@ -41,9 +41,17 @@ defmodule LivebookWeb.AppAuthHook do
   #
 
   def on_mount(:default, %{"slug" => slug}, session, socket) do
+    if connected?(socket) do
+      LivebookWeb.SessionHelpers.subscribe_to_logout()
+    end
+
     livebook_authenticated? = livebook_authenticated?(session, socket)
 
-    socket = assign(socket, livebook_authenticated?: livebook_authenticated?)
+    socket =
+      socket
+      |> assign(livebook_authenticated?: livebook_authenticated?)
+      |> attach_hook(:logout, :handle_info, &handle_info/2)
+      |> attach_hook(:logout, :handle_event, &handle_event/3)
 
     case Livebook.Apps.fetch_settings(slug) do
       {:ok, %{access_type: :public} = app_settings} ->
@@ -70,6 +78,18 @@ defmodule LivebookWeb.AppAuthHook do
     LivebookWeb.AuthPlug.authenticated?(session, uri.port)
   end
 
+  defp handle_info(:logout, socket) do
+    {:halt, redirect(socket, to: ~p"/logout")}
+  end
+
+  defp handle_info(_event, socket), do: {:cont, socket}
+
+  defp handle_event("logout", %{}, socket) do
+    {:halt, LivebookWeb.SessionHelpers.confirm_logout(socket)}
+  end
+
+  defp handle_event(_event, _params, socket), do: {:cont, socket}
+
   defp has_valid_token?(socket, app_settings) do
     connect_params = get_connect_params(socket) || %{}
 

lib/livebook_web/live/hooks/sidebar_hook.ex

@@ -9,6 +9,7 @@ defmodule LivebookWeb.SidebarHook do
   def on_mount(:default, _params, _session, socket) do
     if connected?(socket) do
       Livebook.Hubs.Broadcasts.subscribe([:crud, :connection])
+      LivebookWeb.SessionHelpers.subscribe_to_logout()
       Phoenix.PubSub.subscribe(Livebook.PubSub, "sidebar")
     end
 
@@ -67,18 +68,7 @@ defmodule LivebookWeb.SidebarHook do
   end
 
   defp handle_event("logout", _params, socket) do
-    on_confirm = fn socket ->
+    {:halt, LivebookWeb.SessionHelpers.confirm_logout(socket)}
-      Phoenix.PubSub.broadcast(Livebook.PubSub, "sidebar", :logout)
-      put_flash(socket, :info, "Livebook is logging out. You will be redirected soon.")
-    end
-
-    {:halt,
-     confirm(socket, on_confirm,
-       title: "Log out",
-       description: "Are you sure you want to log out Livebook now?",
-       confirm_text: "Log out",
-       confirm_icon: "logout-box-line"
-     )}
   end
 
   defp handle_event(_event, _params, socket), do: {:cont, socket}