Show reconnect button when connecting to a matching runtime (#113)

* Show reconnect button when connecting to a matching runtime

* Add runtime config test

lib/livebook_web/live/session_live/elixir_standalone_live.ex

@@ -4,8 +4,12 @@ defmodule LivebookWeb.SessionLive.ElixirStandaloneLive do
   alias Livebook.{Session, Runtime}
 
   @impl true
-  def mount(_params, %{"session_id" => session_id}, socket) do
-    {:ok, assign(socket, session_id: session_id, output: nil)}
+  def mount(_params, %{"session_id" => session_id, "current_runtime" => current_runtime}, socket) do
+    if connected?(socket) do
+      Phoenix.PubSub.subscribe(Livebook.PubSub, "sessions:#{session_id}")
+    end
+
+    {:ok, assign(socket, session_id: session_id, output: nil, current_runtime: current_runtime)}
   end
 
   @impl true
@@ -18,7 +22,7 @@ defmodule LivebookWeb.SessionLive.ElixirStandaloneLive do
         as soon as you evaluate the first cell.
       </p>
       <button class="button button-primary" phx-click="init">
-        Connect
+        <%= if(matching_runtime?(@current_runtime), do: "Reconnect", else: "Connect") %>
       </button>
       <%= if @output do %>
         <div class="markdown max-h-20 overflow-y-auto tiny-scrollbar">
@@ -29,10 +33,21 @@ defmodule LivebookWeb.SessionLive.ElixirStandaloneLive do
     """
   end
 
+  defp matching_runtime?(%Runtime.ElixirStandalone{}), do: true
+
+  defp matching_runtime?(_runtime), do: false
+
   @impl true
   def handle_event("init", _params, socket) do
     {:ok, runtime} = Runtime.ElixirStandalone.init()
     Session.connect_runtime(socket.assigns.session_id, runtime)
     {:noreply, socket}
   end
+
+  @impl true
+  def handle_info({:operation, {:set_runtime, _pid, runtime}}, socket) do
+    {:noreply, assign(socket, current_runtime: runtime)}
+  end
+
+  def handle_info(_message, socket), do: {:noreply, socket}
 end

lib/livebook_web/live/session_live/mix_standalone_live.ex

@@ -7,11 +7,16 @@ defmodule LivebookWeb.SessionLive.MixStandaloneLive do
 
   @impl true
   def mount(_params, %{"session_id" => session_id, "current_runtime" => current_runtime}, socket) do
+    if connected?(socket) do
+      Phoenix.PubSub.subscribe(Livebook.PubSub, "sessions:#{session_id}")
+    end
+
     {:ok,
      assign(socket,
        session_id: session_id,
        status: :initial,
-       path: if(current_runtime, do: current_runtime.project_path, else: default_path()),
+       current_runtime: current_runtime,
+       path: initial_path(current_runtime),
        outputs: [],
        emitter: nil
      ), temporary_assigns: [outputs: []]}
@@ -35,7 +40,10 @@ defmodule LivebookWeb.SessionLive.MixStandaloneLive do
             running_paths: [],
             target: nil %>
         </div>
-        <%= content_tag :button, "Connect", class: "button button-primary", phx_click: "init", disabled: not mix_project_root?(@path) %>
+        <%= content_tag :button, if(matching_runtime?(@current_runtime, @path), do: "Reconnect", else: "Connect"),
+          class: "button button-primary",
+          phx_click: "init",
+          disabled: not mix_project_root?(@path) %>
       <% end %>
       <%= if @status != :initial do %>
         <div class="markdown">
@@ -50,6 +58,12 @@ defmodule LivebookWeb.SessionLive.MixStandaloneLive do
     """
   end
 
+  defp matching_runtime?(%Runtime.MixStandalone{} = runtime, path) do
+    Path.expand(runtime.project_path) == Path.expand(path)
+  end
+
+  defp matching_runtime?(_runtime, _path), do: false
+
   @impl true
   def handle_event("set_path", %{"path" => path}, socket) do
     {:noreply, assign(socket, path: path)}
@@ -76,13 +90,21 @@ defmodule LivebookWeb.SessionLive.MixStandaloneLive do
     end
   end
 
+  def handle_info({:operation, {:set_runtime, _pid, runtime}}, socket) do
+    {:noreply, assign(socket, current_runtime: runtime)}
+  end
+
   def handle_info(_, socket), do: {:noreply, socket}
 
   defp add_output(socket, output) do
     assign(socket, outputs: socket.assigns.outputs ++ [{output, Utils.random_id()}])
   end
 
-  defp default_path(), do: File.cwd!() <> "/"
+  defp initial_path(%Runtime.MixStandalone{} = current_runtime) do
+    current_runtime.project_path
+  end
+
+  defp initial_path(_runtime), do: File.cwd!() <> "/"
 
   defp mix_project_root?(path) do
     File.dir?(path) and File.exists?(Path.join(path, "mix.exs"))

lib/livebook_web/live/session_live/runtime_component.ex

@@ -86,23 +86,17 @@ defmodule LivebookWeb.SessionLive.RuntimeComponent do
         <%= if @type == "elixir_standalone" do %>
           <%= live_render @socket, LivebookWeb.SessionLive.ElixirStandaloneLive,
             id: :elixir_standalone_runtime,
-            session: %{"session_id" => @session_id} %>
+            session: %{"session_id" => @session_id, "current_runtime" => @runtime} %>
         <% end %>
         <%= if @type == "mix_standalone" do %>
           <%= live_render @socket, LivebookWeb.SessionLive.MixStandaloneLive,
             id: :mix_standalone_runtime,
-            session: %{
-              "session_id" => @session_id,
-              "current_runtime" => if_matches_type(@runtime, @type)
-            } %>
+            session: %{"session_id" => @session_id, "current_runtime" => @runtime} %>
         <% end %>
         <%= if @type == "attached" do %>
           <%= live_render @socket, LivebookWeb.SessionLive.AttachedLive,
             id: :attached_runtime,
-            session: %{
-              "session_id" => @session_id,
-              "current_runtime" => if_matches_type(@runtime, @type)
-            } %>
+            session: %{"session_id" => @session_id, "current_runtime" => @runtime} %>
         <% end %>
       </div>
     </div>
@@ -113,14 +107,6 @@ defmodule LivebookWeb.SessionLive.RuntimeComponent do
   defp runtime_type_label(%Runtime.MixStandalone{}), do: "Mix standalone"
   defp runtime_type_label(%Runtime.Attached{}), do: "Attached"
 
-  def if_matches_type(runtime, type) do
-    if runtime && runtime_type(runtime) == type do
-      runtime
-    else
-      nil
-    end
-  end
-
   defp runtime_type(%Runtime.ElixirStandalone{}), do: "elixir_standalone"
   defp runtime_type(%Runtime.MixStandalone{}), do: "mix_standalone"
   defp runtime_type(%Runtime.Attached{}), do: "attached"

test/livebook_web/live/session_live_test.exs

@@ -3,7 +3,7 @@ defmodule LivebookWeb.SessionLiveTest do
 
   import Phoenix.LiveViewTest
 
-  alias Livebook.{SessionSupervisor, Session, Delta}
+  alias Livebook.{SessionSupervisor, Session, Delta, Runtime}
 
   setup do
     {:ok, session_id} = SessionSupervisor.create_session()
@@ -166,6 +166,30 @@ defmodule LivebookWeb.SessionLiveTest do
     end
   end
 
+  describe "runtime settings" do
+    test "connecting to elixir standalone updates connect button to reconnect",
+         %{conn: conn, session_id: session_id} do
+      {:ok, view, _} = live(conn, "/sessions/#{session_id}/settings/runtime")
+
+      Phoenix.PubSub.subscribe(Livebook.PubSub, "sessions:#{session_id}")
+
+      [elixir_standalone_view] = live_children(view)
+
+      elixir_standalone_view
+      |> element("button", "Connect")
+      |> render_click()
+
+      assert_receive {:operation, {:set_runtime, _pid, %Runtime.ElixirStandalone{} = runtime}}
+
+      page = render(view)
+      assert page =~ Atom.to_string(runtime.node)
+      assert page =~ "Reconnect"
+      assert page =~ "Disconnect"
+    end
+  end
+
+  # Helpers
+
   defp wait_for_session_update(session_id) do
     # This call is synchronous, so it gives the session time
     # for handling the previously sent change messages.