Migrate WebSocket GenServer (Server) to Connection (#1585)

lib/livebook/web_socket.ex

@@ -2,22 +2,19 @@ defmodule Livebook.WebSocket do
   @moduledoc false
 
   alias Livebook.WebSocket.Client
-  alias LivebookProto.{Request, SessionRequest}
 
   defmodule Connection do
     defstruct [:conn, :websocket, :ref]
 
     @type t :: %__MODULE__{
-            conn: Client.conn(),
+            conn: Client.conn() | nil,
-            websocket: Client.websocket(),
+            websocket: Client.websocket() | nil,
-            ref: Client.ref()
+            ref: Client.ref() | nil
           }
   end
 
-  @type proto :: SessionRequest.t()
+  @type proto :: LivebookProto.SessionRequest.t()
-
+  @typep headers :: Mint.Types.headers()
-  @typep header :: {String.t(), String.t()}
-  @typep headers :: list(header())
 
   @doc """
   Connects with the WebSocket server for given URL and headers.
@@ -36,9 +33,15 @@ defmodule Livebook.WebSocket do
   @doc """
   Disconnects the given WebSocket client.
   """
-  @spec disconnect(Connection.t()) :: :ok
+  @spec disconnect(Connection.t()) :: {:ok, Connection.t()} | {:error, Connection.t(), any()}
   def disconnect(%Connection{} = connection) do
-    Client.disconnect(connection.conn, connection.websocket, connection.ref)
+    case Client.disconnect(connection.conn, connection.websocket, connection.ref) do
+      {:ok, conn, websocket} ->
+        {:ok, %{connection | conn: conn, websocket: websocket, ref: nil}}
+
+      {:error, conn, websocket, reason} ->
+        {:error, %{connection | conn: conn, websocket: websocket}, reason}
+    end
   end
 
   @doc """
@@ -47,29 +50,24 @@ defmodule Livebook.WebSocket do
   @spec send_request(Connection.t(), proto()) ::
           {:ok, Connection.t()}
           | {:error, Connection.t(), Client.ws_error() | Client.mint_error()}
-  def send_request(%Connection{} = connection, %struct{} = data) do
+  def send_request(%Connection{} = connection, data) do
-    type = LivebookProto.request_type(struct)
+    frame = LivebookProto.build_request_frame(data)
-    message = Request.new!(type: {type, data})
-    binary = {:binary, Request.encode(message)}
 
-    case Client.send(connection.conn, connection.websocket, connection.ref, binary) do
+    case Client.send(connection.conn, connection.websocket, connection.ref, frame) do
       {:ok, conn, websocket} ->
         {:ok, %{connection | conn: conn, websocket: websocket}}
 
-      {:error, %Mint.WebSocket{} = websocket, reason} ->
+      {:error, conn, websocket, reason} ->
-        {:error, %{connection | websocket: websocket}, reason}
+        {:error, %{connection | conn: conn, websocket: websocket}, reason}
-
-      {:error, conn, reason} ->
-        {:error, %{connection | conn: conn}, reason}
     end
   end
 
-  @dialyzer {:nowarn_function, receive_response: 1}
-
   @doc """
   Receives a response from the given server.
   """
-  @spec receive_response(Connection.t()) :: Client.receive_fun()
+  @spec receive_response(Connection.t()) ::
+          {:ok, Connection.t(), Client.Response.t() | :connect}
+          | {:error, Connection.t(), Client.Response.t() | term()}
   def receive_response(%Connection{conn: conn, websocket: websocket, ref: ref}) do
     conn
     |> Client.receive(ref, websocket)
@@ -85,12 +83,51 @@ defmodule Livebook.WebSocket do
     {:ok, %Connection{conn: conn, websocket: websocket, ref: ref}, result}
   end
 
-  defp handle_receive({:error, conn, %Client.Response{body: nil, status: status}}, ref) do
+  defp handle_receive({:error, conn, websocket, %Client.Response{body: nil, status: status}}, ref) do
-    {:error, %Connection{conn: conn, ref: ref}, Plug.Conn.Status.reason_phrase(status)}
+    {:error, %Connection{conn: conn, websocket: websocket, ref: ref},
+     Plug.Conn.Status.reason_phrase(status)}
   end
 
-  defp handle_receive({:error, conn, %Client.Response{body: response}}, ref) do
+  defp handle_receive({:error, conn, websocket, %Client.Response{body: response}}, ref) do
     %{type: {:error, error}} = LivebookProto.Response.decode(response)
-    {:error, %Connection{conn: conn, ref: ref}, error}
+    {:error, %Connection{conn: conn, websocket: websocket, ref: ref}, error}
+  end
+
+  defp handle_receive({:error, reason}, ref) do
+    {:error, %Connection{ref: ref}, reason}
+  end
+
+  @doc """
+  Subscribe to WebSocket Server events.
+
+  ## Messages
+
+    * `{:ok, pid, random_id, :connected}`
+    * `{:ok, pid, random_id, %Livebook.WebSocket.Response{}}`
+    * `{:error, pid, random_id, %Livebook.WebSocket.Response{}}`
+    * `{:error, pid, random_id, reason}`
+
+  """
+  @spec subscribe() :: :ok | {:error, {:already_registered, pid()}}
+  def subscribe do
+    Phoenix.PubSub.subscribe(Livebook.PubSub, "websocket:clients")
+  end
+
+  @doc """
+  Unsubscribes from `subscribe/0`.
+  """
+  @spec unsubscribe() :: :ok
+  def unsubscribe do
+    Phoenix.PubSub.unsubscribe(Livebook.PubSub, "websocket:clients")
+  end
+
+  @doc """
+  Notifies interested processes about WebSocket Server messages.
+
+  Broadcasts the given message under the `"websocket:clients"` topic.
+  """
+  @spec broadcast_message(any()) :: :ok
+  def broadcast_message(message) do
+    Phoenix.PubSub.broadcast(Livebook.PubSub, "websocket:clients", message)
   end
 end

lib/livebook/web_socket/client.ex

@@ -7,7 +7,7 @@ defmodule Livebook.WebSocket.Client do
 
   @type conn :: Mint.HTTP.t()
   @type websocket :: Mint.WebSocket.t()
-  @type frame :: :close | {:binary, binary()}
+  @type frame :: Mint.WebSocket.frame() | Mint.WebSocket.shorthand_frame()
   @type ref :: Mint.Types.request_ref()
   @type ws_error :: Mint.WebSocket.error()
   @type mint_error :: Mint.Types.error()
@@ -16,9 +16,9 @@ defmodule Livebook.WebSocket.Client do
     defstruct [:body, :status, :headers]
 
     @type t :: %__MODULE__{
-            body: Livebook.WebSocket.Response.t(),
+            body: Livebook.WebSocket.Response.t() | nil,
-            status: Mint.Types.status(),
+            status: Mint.Types.status() | nil,
-            headers: Mint.Types.headers()
+            headers: Mint.Types.headers() | nil
           }
   end
 
@@ -53,15 +53,19 @@ defmodule Livebook.WebSocket.Client do
 
   If there's no WebSocket connection yet, it'll only close the HTTP connection.
   """
-  @spec disconnect(conn(), websocket(), ref()) :: :ok
+  @spec disconnect(conn(), websocket() | nil, ref()) ::
+          {:ok, conn(), websocket() | nil}
+          | {:error, conn() | websocket(), term()}
+  def disconnect(conn, nil, _ref) do
+    {:ok, conn} = Mint.HTTP.close(conn)
+    {:ok, conn, nil}
+  end
+
   def disconnect(conn, websocket, ref) do
-    if websocket do
+    with {:ok, conn, websocket} <- send(conn, websocket, ref, :close),
-      send(conn, websocket, ref, :close)
+         {:ok, conn} <- Mint.HTTP.close(conn) do
+      {:ok, conn, websocket}
     end
-
-    Mint.HTTP.close(conn)
-
-    :ok
   end
 
   @doc """
@@ -70,17 +74,24 @@ defmodule Livebook.WebSocket.Client do
   If the WebSocket isn't connected yet, it will try to get the connection
   response to start a new WebSocket connection.
   """
-  @spec receive(conn(), ref(), term()) ::
+  @spec receive(conn() | nil, ref(), websocket() | nil, term()) ::
-          {:ok, conn(), Response.t() | :connect}
+          {:ok, conn(), websocket(), Response.t() | :connected}
-          | {:error, conn(), Response.t()}
+          | {:error, conn(), websocket(), Response.t()}
-          | {:error, conn(), :unknown}
+          | {:error, conn(), websocket(), ws_error() | mint_error()}
+          | {:error, :not_connected | :unknown}
   def receive(conn, ref, websocket \\ nil, message \\ receive(do: (message -> message))) do
+    do_receive(conn, ref, websocket, message)
+  end
+
+  defp do_receive(nil, _ref, _websocket, _message), do: {:error, :not_connected}
+
+  defp do_receive(conn, ref, websocket, message) do
     case Mint.WebSocket.stream(conn, message) do
       {:ok, conn, responses} ->
         handle_responses(conn, ref, websocket, responses)
 
       {:error, conn, reason, []} ->
-        {:error, conn, reason}
+        {:error, conn, websocket, reason}
 
       {:error, conn, _reason, responses} ->
         handle_responses(conn, ref, websocket, responses)
@@ -92,24 +103,6 @@ defmodule Livebook.WebSocket.Client do
 
   @successful_status 100..299
 
-  defp handle_responses(conn, ref, nil, responses) do
-    result =
-      Enum.reduce(responses, %Response{}, fn
-        {:status, ^ref, status}, acc -> %{acc | status: status}
-        {:headers, ^ref, headers}, acc -> %{acc | headers: headers}
-        {:data, ^ref, body}, acc -> %{acc | body: body}
-        {:done, ^ref}, acc -> handle_done_response(conn, ref, acc)
-      end)
-
-    case result do
-      %Response{} = response when response.status not in @successful_status ->
-        {:error, conn, response}
-
-      result ->
-        result
-    end
-  end
-
   defp handle_responses(conn, ref, websocket, [{:data, ref, data}]) do
     with {:ok, websocket, frames} <- Mint.WebSocket.decode(websocket, data) do
       case handle_frames(%Response{}, frames) do
@@ -120,8 +113,7 @@ defmodule Livebook.WebSocket.Client do
           {:ok, conn, websocket, response}
 
         {:close, result} ->
-          disconnect(conn, websocket, ref)
+          handle_disconnect(conn, websocket, ref, result)
-          {:ok, conn, websocket, result}
 
         {:error, response} ->
           {:error, conn, websocket, response}
@@ -129,7 +121,25 @@ defmodule Livebook.WebSocket.Client do
     end
   end
 
-  defp handle_done_response(conn, ref, response) do
+  defp handle_responses(conn, ref, websocket, [_ | _] = responses) do
+    result =
+      Enum.reduce(responses, %Response{}, fn
+        {:status, ^ref, status}, acc -> %{acc | status: status}
+        {:headers, ^ref, headers}, acc -> %{acc | headers: headers}
+        {:data, ^ref, body}, acc -> %{acc | body: body}
+        {:done, ^ref}, acc -> handle_done_response(conn, ref, websocket, acc)
+      end)
+
+    case result do
+      %Response{} = response when response.status not in @successful_status ->
+        {:error, conn, websocket, response}
+
+      result ->
+        result
+    end
+  end
+
+  defp handle_done_response(conn, ref, websocket, response) do
     case Mint.WebSocket.new(conn, ref, response.status, response.headers) do
       {:ok, conn, websocket} ->
         case decode_response(websocket, response) do
@@ -137,15 +147,20 @@ defmodule Livebook.WebSocket.Client do
             {:ok, conn, websocket, result}
 
           {websocket, {:close, result}} ->
-            disconnect(conn, websocket, ref)
+            handle_disconnect(conn, websocket, ref, result)
-            {:ok, conn, websocket, result}
 
           {websocket, {:error, reason}} ->
             {:error, conn, websocket, reason}
         end
 
       {:error, conn, %UpgradeFailureError{status_code: status, headers: headers}} ->
-        {:error, conn, %{response | status: status, headers: headers}}
+        {:error, conn, websocket, %{response | status: status, headers: headers}}
+    end
+  end
+
+  defp handle_disconnect(conn, websocket, ref, result) do
+    with {:ok, conn, websocket} <- disconnect(conn, websocket, ref) do
+      {:ok, conn, websocket, result}
     end
   end
 
@@ -173,18 +188,22 @@ defmodule Livebook.WebSocket.Client do
     end)
   end
 
-  @dialyzer {:nowarn_function, send: 4}
-
   @doc """
   Sends a message to the given HTTP Connection and WebSocket connection.
   """
   @spec send(conn(), websocket(), ref(), frame()) ::
           {:ok, conn(), websocket()}
-          | {:error, conn() | websocket(), term()}
+          | {:error, conn(), websocket(), term()}
   def send(conn, websocket, ref, frame) when is_frame(frame) do
     with {:ok, websocket, data} <- Mint.WebSocket.encode(websocket, frame),
          {:ok, conn} <- Mint.WebSocket.stream_request_body(conn, ref, data) do
       {:ok, conn, websocket}
+    else
+      {:error, %Mint.HTTP1{} = conn, reason} ->
+        {:error, conn, websocket, reason}
+
+      {:error, websocket, reason} ->
+        {:error, conn, websocket, reason}
     end
   end
 end

lib/livebook/web_socket/server.ex

@@ -1,115 +1,196 @@
 defmodule Livebook.WebSocket.Server do
   @moduledoc false
-  use GenServer
+  use Connection
 
   require Logger
 
-  import Livebook.WebSocket.Client, only: [is_frame: 1]
+  alias Livebook.WebSocket
-
   alias Livebook.WebSocket.Client
 
-  defstruct [
+  @timeout 10_000
-    :conn,
+  @backoff 1_490
-    :websocket,
-    :caller,
-    :status,
-    :resp_headers,
-    :resp_body,
-    :ref,
-    closing?: false
-  ]
 
-  def start_link(opts \\ []) do
+  defstruct [:url, :headers, :http_conn, :websocket, :ref, id: 0]
-    GenServer.start_link(__MODULE__, opts)
+
+  @doc """
+  Starts a new WebSocket Server connection with given URL and headers.
+  """
+  @spec start_link(String.t(), Mint.Types.headers()) ::
+          {:ok, pid()} | {:error, {:already_started, pid()}}
+  def start_link(url, headers \\ []) do
+    Connection.start_link(__MODULE__, {url, headers})
   end
 
   @doc """
-  Connects the WebSocket client.
+  Checks if the given WebSocket Server is connected.
   """
-  def connect(pid, url, headers \\ []) do
+  @spec connected?(pid()) :: boolean()
-    GenServer.call(pid, {:connect, url, headers})
+  def connected?(conn) do
+    Connection.call(conn, :connected?, @timeout)
   end
 
   @doc """
-  Disconnects the WebSocket client.
+  Closes the given WebSocket Server connection.
   """
-  def disconnect(pid) do
+  @spec close(pid()) :: :ok
-    GenServer.cast(pid, :close)
+  def close(conn) do
+    Connection.call(conn, :close, @timeout)
   end
 
   @doc """
-  Sends a message to the WebSocket server the message request.
+  Sends a Request to given WebSocket Server.
   """
-  def send_message(socket, frame) when is_frame(frame) do
+  @spec send_request(pid(), WebSocket.proto()) :: :ok
-    GenServer.cast(socket, {:send_message, frame})
+  def send_request(conn, %_struct{} = data) do
+    Connection.call(conn, {:request, data}, @timeout)
+  end
+
+  ## Connection callbacks
+
+  @impl true
+  def init({url, headers}) do
+    state = struct!(__MODULE__, url: url, headers: headers)
+    {:connect, :init, state}
+  end
+
+  @impl true
+  def connect(_, state) do
+    case Client.connect(state.url, state.headers) do
+      {:ok, conn, ref} ->
+        {:ok, %{state | http_conn: conn, ref: ref}}
+
+      {:error, exception} when is_exception(exception) ->
+        Logger.error("Received exception: #{Exception.message(exception)}")
+        {:backoff, @backoff, state}
+
+      {:error, conn, reason} ->
+        Logger.error("Received error: #{inspect(reason)}")
+        {:backoff, @backoff, %{state | http_conn: conn}}
+    end
+  end
+
+  @dialyzer {:nowarn_function, disconnect: 2}
+
+  @impl true
+  def disconnect({:close, caller}, state) do
+    case Client.disconnect(state.http_conn, state.websocket, state.ref) do
+      {:ok, conn, websocket} ->
+        Connection.reply(caller, :ok)
+        {:noconnect, %{state | http_conn: conn, websocket: websocket}}
+
+      {:error, conn, websocket, reason} ->
+        Connection.reply(caller, {:error, reason})
+        {:noconnect, %{state | http_conn: conn, websocket: websocket}}
+    end
+  end
+
+  def disconnect(info, state) do
+    case info do
+      {:error, :closed} -> Logger.error("Connection closed")
+      {:error, reason} -> Logger.error("Connection error: #{inspect(reason)}")
+    end
+
+    case Client.disconnect(state.http_conn, state.websocket, state.ref) do
+      {:ok, conn, websocket} ->
+        {:connect, :reconnect, %{state | http_conn: conn, websocket: websocket}}
+
+      {:error, conn, websocket, reason} ->
+        Logger.error("Received error: #{inspect(reason)}")
+        {:connect, :reconnect, %{state | http_conn: conn, websocket: websocket}}
+    end
   end
 
   ## GenServer callbacks
 
   @impl true
-  def init(_) do
+  def handle_call(:connected?, _from, state) do
-    {:ok, %__MODULE__{}}
+    if conn = state.http_conn do
-  end
+      {:reply, conn.state == :open, state}
-
+    else
-  @impl true
+      {:reply, false, state}
-  def handle_call({:connect, url, headers}, from, state) do
-    case Client.connect(url, headers) do
-      {:ok, conn, ref} -> {:noreply, %{state | conn: conn, ref: ref, caller: from}}
-      {:error, _reason} = error -> {:reply, error, state}
-      {:error, conn, reason} -> {:reply, {:error, reason}, %{state | conn: conn}}
     end
   end
 
-  @impl true
+  def handle_call(:close, caller, state) do
-  def handle_cast(:close, state) do
+    {:disconnect, {:close, caller}, state}
-    Client.disconnect(state.conn, state.websocket, state.ref)
-
-    {:stop, :normal, state}
   end
 
-  def handle_cast({:send_message, frame}, state) do
+  def handle_call({:request, data}, caller, state) do
-    case Client.send(state.conn, state.websocket, state.ref, frame) do
+    id = state.id
+    frame = LivebookProto.build_request_frame(data, id)
+    Connection.reply(caller, :ok)
+
+    case Client.send(state.http_conn, state.websocket, state.ref, frame) do
       {:ok, conn, websocket} ->
-        {:noreply, %{state | conn: conn, websocket: websocket}}
+        {:noreply, %{state | http_conn: conn, websocket: websocket, id: id + 1}}
 
-      {:error, %Mint.WebSocket{} = websocket, _reason} ->
+      {:error, conn, websocket, reason} ->
-        {:noreply, %{state | websocket: websocket}}
+        WebSocket.broadcast_message({:error, self(), id, reason})
-
+        {:noreply, %{state | http_conn: conn, websocket: websocket}}
-      {:error, conn, _reason} ->
-        {:noreply, %{state | conn: conn}}
     end
   end
 
   @impl true
   def handle_info(message, state) do
-    case Client.receive(state.conn, state.ref, state.websocket, message) do
+    case Client.receive(state.http_conn, state.ref, state.websocket, message) do
-      {:ok, conn, websocket, response} ->
+      {:ok, conn, websocket, :connected} ->
-        state = %{state | conn: conn, websocket: websocket}
+        {:ok, :connected}
-        {:noreply, reply(state, {:ok, response})}
+        |> build_response(state)
+        |> WebSocket.broadcast_message()
 
-      {:error, conn, websocket, response} ->
+        {:noreply, %{state | http_conn: conn, websocket: websocket}}
-        state = %{state | conn: conn, websocket: websocket}
-        {:noreply, reply(state, {:error, response})}
 
-      {:error, conn, response} ->
+      {:error, conn, websocket, %Mint.TransportError{} = reason} ->
-        state = %{state | conn: conn}
+        {:error, reason}
-        {:noreply, reply(state, {:error, response})}
+        |> build_response(state)
+        |> WebSocket.broadcast_message()
+
+        {:connect, :receive, %{state | http_conn: conn, websocket: websocket}}
+
+      {term, conn, websocket, data} ->
+        {term, data}
+        |> build_response(state)
+        |> WebSocket.broadcast_message()
+
+        {:noreply, %{state | http_conn: conn, websocket: websocket}}
+
+      {:error, _} = error ->
+        error
+        |> build_response(state)
+        |> WebSocket.broadcast_message()
 
-      {:error, _} ->
         {:noreply, state}
     end
   end
 
   # Private
 
-  defp reply(%{caller: nil} = state, response) do
+  defp build_response({:ok, :connected}, state) do
-    Logger.warning("The caller is nil, so we can't reply the message: #{inspect(response)}")
+    {:ok, self(), state.id, :connected}
-    state
   end
 
-  defp reply(state, response) do
+  defp build_response({:ok, %Client.Response{body: nil, status: nil, headers: nil}}, state) do
-    GenServer.reply(state.caller, response)
+    {:ok, self(), state.id, :pong}
+  end
 
-    state
+  defp build_response({:error, %Client.Response{body: nil, status: status} = response}, state) do
+    response = %{response | body: Plug.Conn.Status.reason_phrase(status)}
+    {:error, self(), state.id, response}
+  end
+
+  defp build_response({:ok, %Client.Response{body: body} = response}, _state) do
+    case LivebookProto.Response.decode(body) do
+      %{id: id, type: {:error, _} = error} -> {:error, self(), id, %{response | body: error}}
+      %{id: id, type: result} -> {:ok, self(), id, result}
+    end
+  end
+
+  defp build_response({:error, %Client.Response{body: body} = response}, _state) do
+    %{id: id, type: {:error, _} = error} = LivebookProto.Response.decode(body)
+    {:error, self(), id, %{response | body: error}}
+  end
+
+  defp build_response({:error, reason}, state) do
+    {:error, self(), state.id, %Client.Response{body: reason}}
   end
 end

mix.exs

@@ -106,7 +106,8 @@ defmodule Livebook.MixProject do
       {:protobuf, "~> 0.8.0"},
       {:phoenix_live_reload, "~> 1.2", only: :dev},
       {:floki, ">= 0.27.0", only: :test},
-      {:bypass, "~> 2.1", only: :test}
+      {:bypass, "~> 2.1", only: :test},
+      {:connection, "~> 1.1.0"}
     ]
   end
 

mix.lock

@@ -2,6 +2,7 @@
   "aws_signature": {:hex, :aws_signature, "0.3.1", "67f369094cbd55ffa2bbd8cc713ede14b195fcfb45c86665cd7c5ad010276148", [:rebar3], [], "hexpm", "50fc4dc1d1f7c2d0a8c63f455b3c66ecd74c1cf4c915c768a636f9227704a674"},
   "bypass": {:hex, :bypass, "2.1.0", "909782781bf8e20ee86a9cabde36b259d44af8b9f38756173e8f5e2e1fabb9b1", [:mix], [{:plug, "~> 1.7", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 2.0", [hex: :plug_cowboy, repo: "hexpm", optional: false]}, {:ranch, "~> 1.3", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm", "d9b5df8fa5b7a6efa08384e9bbecfe4ce61c77d28a4282f79e02f1ef78d96b80"},
   "castore": {:hex, :castore, "0.1.18", "deb5b9ab02400561b6f5708f3e7660fc35ca2d51bfc6a940d2f513f89c2975fc", [:mix], [], "hexpm", "61bbaf6452b782ef80b33cdb45701afbcf0a918a45ebe7e73f1130d661e66a06"},
+  "connection": {:hex, :connection, "1.1.0", "ff2a49c4b75b6fb3e674bfc5536451607270aac754ffd1bdfe175abe4a6d7a68", [:mix], [], "hexpm", "722c1eb0a418fbe91ba7bd59a47e28008a189d47e37e0e7bb85585a016b2869c"},
   "cowboy": {:hex, :cowboy, "2.9.0", "865dd8b6607e14cf03282e10e934023a1bd8be6f6bacf921a7e2a96d800cd452", [:make, :rebar3], [{:cowlib, "2.11.0", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "1.8.0", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm", "2c729f934b4e1aa149aff882f57c6372c15399a20d54f65c8d67bef583021bde"},
   "cowboy_telemetry": {:hex, :cowboy_telemetry, "0.4.0", "f239f68b588efa7707abce16a84d0d2acf3a0f50571f8bb7f56a15865aae820c", [:rebar3], [{:cowboy, "~> 2.7", [hex: :cowboy, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "7d98bac1ee4565d31b62d59f8823dfd8356a169e7fcbb83831b8a5397404c9de"},
   "cowlib": {:hex, :cowlib, "2.11.0", "0b9ff9c346629256c42ebe1eeb769a83c6cb771a6ee5960bd110ab0b9b872063", [:make, :rebar3], [], "hexpm", "2b3e9da0b21c4565751a6d4901c20d1b4cc25cbb7fd50d91d2ab6dd287bc86a9"},

proto/lib/livebook_proto.ex

@@ -1,10 +1,19 @@
 defmodule LivebookProto do
   @moduledoc false
 
-  @mapping (for {_id, field_prop} <- LivebookProto.Request.__message_props__().field_props,
+  alias LivebookProto.Request
+
+  @mapping (for {_id, field_prop} <- Request.__message_props__().field_props,
                 into: %{} do
               {field_prop.type, field_prop.name_atom}
             end)
 
-  def request_type(module), do: Map.fetch!(@mapping, module)
+  def build_request_frame(%struct{} = data, id \\ -1) do
+    type = request_type(struct)
+    message = Request.new!(id: id, type: {type, data})
+
+    {:binary, Request.encode(message)}
+  end
+
+  defp request_type(module), do: Map.fetch!(@mapping, module)
 end

proto/lib/livebook_proto/request.pb.ex

@@ -4,5 +4,6 @@ defmodule LivebookProto.Request do
 
   oneof :type, 0
 
-  field :session, 1, type: LivebookProto.SessionRequest, oneof: 0
+  field :id, 1, type: :int32
+  field :session, 2, type: LivebookProto.SessionRequest, oneof: 0
 end

proto/lib/livebook_proto/response.pb.ex

@@ -4,6 +4,7 @@ defmodule LivebookProto.Response do
 
   oneof :type, 0
 
-  field :error, 1, type: LivebookProto.Error, oneof: 0
+  field :id, 1, type: :int32
-  field :session, 2, type: LivebookProto.SessionResponse, oneof: 0
+  field :error, 2, type: LivebookProto.Error, oneof: 0
+  field :session, 3, type: LivebookProto.SessionResponse, oneof: 0
 end

proto/messages.proto

@@ -19,15 +19,19 @@ message SessionResponse {
 }
 
 message Request {
+  int32 id = 1;
+
   oneof type {
-    SessionRequest session = 1;
+    SessionRequest session = 2;
   }
 }
 
 message Response {
-  oneof type {
+  int32 id = 1;
-    Error error = 1;
 
-    SessionResponse session = 2;
+  oneof type {
+    Error error = 2;
+
+    SessionResponse session = 3;
   }
 }

test/livebook/web_socket/client_test.exs

@@ -1,7 +1,10 @@
 defmodule Livebook.WebSocket.ClientTest do
   use Livebook.EnterpriseIntegrationCase, async: true
 
+  @app_version Mix.Project.config()[:version]
+
   alias Livebook.WebSocket.Client
+  alias LivebookProto.Request
 
   describe "connect/2" do
     test "successfully authenticates the websocket connection", %{url: url, token: token} do
@@ -9,7 +12,7 @@ defmodule Livebook.WebSocket.ClientTest do
 
       assert {:ok, conn, ref} = Client.connect(url, headers)
       assert {:ok, conn, websocket, :connected} = Client.receive(conn, ref)
-      assert Client.disconnect(conn, websocket, ref) == :ok
+      assert {:ok, _conn, _websocket} = Client.disconnect(conn, websocket, ref)
     end
 
     test "rejects the websocket with invalid address", %{token: token} do
@@ -23,7 +26,7 @@ defmodule Livebook.WebSocket.ClientTest do
       headers = [{"X-Auth-Token", "foo"}]
 
       assert {:ok, conn, ref} = Client.connect(url, headers)
-      assert {:error, _conn, response} = Client.receive(conn, ref)
+      assert {:error, _conn, nil, response} = Client.receive(conn, ref)
 
       assert response.status == 403
 
@@ -31,7 +34,7 @@ defmodule Livebook.WebSocket.ClientTest do
       assert error =~ "the given token is invalid"
 
       assert {:ok, conn, ref} = Client.connect(url)
-      assert {:error, _conn, response} = Client.receive(conn, ref)
+      assert {:error, _conn, nil, response} = Client.receive(conn, ref)
 
       assert response.status == 401
 
@@ -39,4 +42,36 @@ defmodule Livebook.WebSocket.ClientTest do
       assert error =~ "could not get the token from the connection"
     end
   end
+
+  describe "send/2" do
+    setup %{url: url, token: token} do
+      headers = [{"X-Auth-Token", token}]
+
+      {:ok, conn, ref} = Client.connect(url, headers)
+      {:ok, conn, websocket, :connected} = Client.receive(conn, ref)
+
+      on_exit(fn -> Client.disconnect(conn, websocket, ref) end)
+
+      {:ok, conn: conn, websocket: websocket, ref: ref}
+    end
+
+    test "successfully sends a session message", %{
+      conn: conn,
+      websocket: websocket,
+      ref: ref,
+      user: %{id: id, email: email}
+    } do
+      session_request = LivebookProto.SessionRequest.new!(app_version: @app_version)
+      request = Request.new!(type: {:session, session_request})
+      frame = {:binary, Request.encode(request)}
+
+      assert {:ok, conn, websocket} = Client.send(conn, websocket, ref, frame)
+
+      assert {:ok, ^conn, ^websocket, %Client.Response{body: body}} =
+               Client.receive(conn, ref, websocket)
+
+      assert %{type: result} = LivebookProto.Response.decode(body)
+      assert {:session, %{id: _, user: %{id: ^id, email: ^email}}} = result
+    end
+  end
 end

test/livebook/web_socket/server_test.exs

@@ -1,47 +1,132 @@
 defmodule Livebook.WebSocket.ServerTest do
   use Livebook.EnterpriseIntegrationCase, async: true
 
-  alias Livebook.WebSocket.Server
+  @app_version Mix.Project.config()[:version]
+  @moduletag :capture_log
 
-  describe "connect/2" do
+  alias Livebook.WebSocket.Server
+  alias Livebook.WebSocket.Client.Response
+
+  setup do
+    Livebook.WebSocket.subscribe()
+
+    :ok
+  end
+
+  describe "connect" do
     test "successfully authenticates the websocket connection", %{url: url, token: token} do
       headers = [{"X-Auth-Token", token}]
 
-      assert {:ok, pid} = Server.start_link()
+      assert {:ok, conn} = Server.start_link(url, headers)
-      assert {:ok, :connected} = Server.connect(pid, url, headers)
+      assert_receive {:ok, ^conn, _id, :connected}
-      assert Server.disconnect(pid) == :ok
+      assert Server.connected?(conn)
     end
 
     test "rejects the websocket with invalid address", %{token: token} do
       headers = [{"X-Auth-Token", token}]
 
-      assert {:ok, pid} = Server.start_link()
+      assert {:ok, conn} = Server.start_link("http://localhost:9999", headers)
-
+      refute Server.connected?(conn)
-      assert {:error, %Mint.TransportError{reason: :econnrefused}} =
-               Server.connect(pid, "http://localhost:9999", headers)
-
-      assert Server.disconnect(pid) == :ok
     end
 
     test "rejects the websocket connection with invalid credentials", %{url: url} do
       headers = [{"X-Auth-Token", "foo"}]
 
-      assert {:ok, pid} = Server.start_link()
+      assert {:ok, conn} = Server.start_link(url, headers)
-      assert {:error, response} = Server.connect(pid, url, headers)
 
-      assert response.status == 403
+      assert_receive {:error, ^conn, -1, response}
+      assert %Response{body: {:error, %{details: error}}, status: 403} = response
 
-      assert %{type: {:error, %{details: error}}} = LivebookProto.Response.decode(response.body)
       assert error =~ "the given token is invalid"
+      assert Server.close(conn) == :ok
 
-      assert {:error, response} = Server.connect(pid, url)
+      assert {:ok, conn} = Server.start_link(url)
 
-      assert response.status == 401
+      assert_receive {:error, ^conn, -1, response}
+      assert %Response{body: {:error, %{details: error}}, status: 401} = response
 
-      assert %{type: {:error, %{details: error}}} = LivebookProto.Response.decode(response.body)
       assert error =~ "could not get the token from the connection"
+      assert Server.close(conn) == :ok
+    end
+  end
 
-      assert Server.disconnect(pid) == :ok
+  describe "send_request/2" do
+    setup %{url: url, token: token} do
+      headers = [{"X-Auth-Token", token}]
+
+      {:ok, conn} = Server.start_link(url, headers)
+
+      assert_receive {:ok, ^conn, _id, :connected}
+
+      {:ok, conn: conn}
+    end
+
+    test "successfully sends a session request", %{
+      conn: conn,
+      user: %{id: id, email: email}
+    } do
+      session_request = LivebookProto.SessionRequest.new!(app_version: @app_version)
+
+      assert Server.send_request(conn, session_request) == :ok
+      assert_receive {:ok, ^conn, 0, {:session, response}}
+      assert %{id: _, user: %{id: ^id, email: ^email}} = response
+    end
+  end
+
+  describe "reconnect event" do
+    setup %{test: name} do
+      suffix = Ecto.UUID.generate() |> :erlang.phash2() |> to_string()
+      app_port = Enum.random(1000..9000) |> to_string()
+
+      {:ok, _} =
+        EnterpriseServer.start(name,
+          env: %{"ENTERPRISE_DB_SUFFIX" => suffix},
+          app_port: app_port
+        )
+
+      url = EnterpriseServer.url(name)
+      token = EnterpriseServer.token(name)
+      headers = [{"X-Auth-Token", token}]
+
+      assert {:ok, conn} = Server.start_link(url, headers)
+
+      assert_receive {:ok, ^conn, _id, :connected}
+      assert Server.connected?(conn)
+
+      on_exit(fn ->
+        EnterpriseServer.disconnect(name)
+        EnterpriseServer.drop_database(name)
+      end)
+
+      {:ok, conn: conn}
+    end
+
+    test "receives the disconnect message from websocket server", %{conn: conn, test: name} do
+      EnterpriseServer.disconnect(name)
+
+      assert_receive {:error, ^conn, 0, %Response{body: reason}}
+      assert %Mint.TransportError{reason: :closed} = reason
+
+      assert Process.alive?(conn)
+      refute Server.connected?(conn)
+    end
+
+    test "reconnects after websocket server is up", %{conn: conn, test: name} do
+      EnterpriseServer.disconnect(name)
+
+      assert_receive {:error, ^conn, 0, %Response{body: reason}}
+      assert %Mint.TransportError{reason: :closed} = reason
+
+      Process.sleep(1000)
+      refute Server.connected?(conn)
+
+      # Wait until the server is up again
+      assert EnterpriseServer.reconnect(name) == :ok
+      assert_receive {:ok, ^conn, 0, :connected}, 5000
+
+      assert Server.connected?(conn)
+      assert Server.close(conn) == :ok
+      refute Server.connected?(conn)
     end
   end
 end

test/livebook/web_socket_test.exs

@@ -10,7 +10,7 @@ defmodule Livebook.WebSocketTest do
       headers = [{"X-Auth-Token", token}]
 
       assert {:ok, connection, :connected} = WebSocket.connect(url, headers)
-      assert WebSocket.disconnect(connection) == :ok
+      assert {:ok, _connection} = WebSocket.disconnect(connection)
     end
 
     test "rejects the web socket connection with invalid credentials", %{url: url} do
@@ -18,33 +18,36 @@ defmodule Livebook.WebSocketTest do
 
       assert {:error, connection, %{details: error}} = WebSocket.connect(url, headers)
       assert error =~ "the given token is invalid"
-      assert WebSocket.disconnect(connection) == :ok
+      assert {:ok, _connection} = WebSocket.disconnect(connection)
 
       assert {:error, connection, %{details: error}} = WebSocket.connect(url)
       assert error =~ "could not get the token from the connection"
-      assert WebSocket.disconnect(connection) == :ok
+      assert {:ok, _connection} = WebSocket.disconnect(connection)
     end
   end
 
   describe "send_request/2" do
-    test "receives the session response from server", %{url: url, token: token, user: user} do
+    setup %{url: url, token: token} do
       headers = [{"X-Auth-Token", token}]
 
-      assert {:ok, %WebSocket.Connection{} = connection, :connected} =
+      {:ok, %WebSocket.Connection{} = connection, :connected} = WebSocket.connect(url, headers)
-               WebSocket.connect(url, headers)
 
+      on_exit(fn -> WebSocket.disconnect(connection) end)
+
+      {:ok, connection: connection}
+    end
+
+    test "successfully sends a session message", %{
+      connection: connection,
+      user: %{id: id, email: email}
+    } do
       session_request = LivebookProto.SessionRequest.new!(app_version: @app_version)
 
       assert {:ok, %WebSocket.Connection{} = connection} =
                WebSocket.send_request(connection, session_request)
 
-      assert {:ok, connection, {:session, session_response}} =
+      assert {:ok, ^connection, response} = WebSocket.receive_response(connection)
-               WebSocket.receive_response(connection)
+      assert {:session, %{id: _, user: %{id: ^id, email: ^email}}} = response
-
-      assert WebSocket.disconnect(connection) == :ok
-
-      assert session_response.user.id == user.id
-      assert session_response.user.email == user.email
     end
   end
 end

test/support/integration/enterprise_server.ex

@@ -2,53 +2,100 @@ defmodule Livebook.EnterpriseServer do
   @moduledoc false
   use GenServer
 
-  defstruct [:token, :user, :node, :port]
+  defstruct [:token, :user, :node, :port, :app_port, :url, :env]
 
   @name __MODULE__
+  @timeout 10_000
 
-  def start do
+  def start(name \\ @name, opts \\ []) do
-    GenServer.start(__MODULE__, [], name: @name)
+    GenServer.start(__MODULE__, opts, name: name)
   end
 
-  def url do
+  def url(name \\ @name) do
-    "http://localhost:#{app_port()}"
+    GenServer.call(name, :fetch_url, @timeout)
   end
 
-  def token do
+  def token(name \\ @name) do
-    GenServer.call(@name, :fetch_token)
+    GenServer.call(name, :fetch_token, @timeout)
   end
 
-  def user do
+  def user(name \\ @name) do
-    GenServer.call(@name, :fetch_user)
+    GenServer.call(name, :fetch_user, @timeout)
+  end
+
+  def drop_database(name \\ @name) do
+    GenServer.cast(name, :drop_database)
+  end
+
+  def reconnect(name \\ @name) do
+    GenServer.cast(name, :reconnect)
+  end
+
+  def disconnect(name \\ @name) do
+    GenServer.cast(name, :disconnect)
   end
 
   # GenServer Callbacks
 
   @impl true
-  def init(_opts) do
+  def init(opts) do
-    state = %__MODULE__{node: enterprise_node()}
+    state = struct(__MODULE__, opts)
-    {:ok, state, {:continue, :start_enterprise}}
+
+    {:ok, %{state | node: enterprise_node()}, {:continue, :start_enterprise}}
   end
 
   @impl true
   def handle_continue(:start_enterprise, state) do
+    ensure_app_dir!()
+    prepare_database(state)
+
     {:noreply, %{state | port: start_enterprise(state)}}
   end
 
   @impl true
   def handle_call(:fetch_token, _from, state) do
-    state = if _ = state.token, do: state, else: create_enterprise_token(state)
+    state = if state.token, do: state, else: create_enterprise_token(state)
 
     {:reply, state.token, state}
   end
 
   @impl true
   def handle_call(:fetch_user, _from, state) do
-    state = if _ = state.user, do: state, else: create_enterprise_user(state)
+    state = if state.user, do: state, else: create_enterprise_user(state)
 
     {:reply, state.user, state}
   end
 
+  @impl true
+  def handle_call(:fetch_url, _from, state) do
+    state = if state.app_port, do: state, else: %{state | app_port: app_port()}
+    url = state.url || fetch_url(state)
+
+    {:reply, url, %{state | url: url}}
+  end
+
+  @impl true
+  def handle_cast(:drop_database, state) do
+    :ok = mix(state, ["ecto.drop", "--quiet"])
+    {:noreply, state}
+  end
+
+  def handle_cast(:reconnect, state) do
+    if state.port do
+      {:noreply, state}
+    else
+      {:noreply, %{state | port: start_enterprise(state)}}
+    end
+  end
+
+  def handle_cast(:disconnect, state) do
+    if state.port do
+      Port.close(state.port)
+    end
+
+    {:noreply, %{state | port: nil}}
+  end
+
   # Port Callbacks
 
   @impl true
@@ -85,14 +132,10 @@ defmodule Livebook.EnterpriseServer do
   end
 
   defp start_enterprise(state) do
-    ensure_app_dir!()
+    env =
-    prepare_database()
+      for {key, value} <- env(state), into: [] do
-
+        {String.to_charlist(key), String.to_charlist(value)}
-    env = [
+      end
-      {~c"MIX_ENV", ~c"livebook"},
-      {~c"LIVEBOOK_ENTERPRISE_PORT", String.to_charlist(app_port())},
-      {~c"LIVEBOOK_ENTERPRISE_DEBUG", String.to_charlist(debug?())}
-    ]
 
     args = [
       "-e",
@@ -118,13 +161,18 @@ defmodule Livebook.EnterpriseServer do
         args: args
       ])
 
-    wait_on_start(port)
+    wait_on_start(state, port)
   end
 
-  defp prepare_database do
+  defp fetch_url(state) do
-    mix(["ecto.drop", "--quiet"])
+    port = state.app_port || app_port()
-    mix(["ecto.create", "--quiet"])
+    "http://localhost:#{port}"
-    mix(["ecto.migrate", "--quiet"])
+  end
+
+  defp prepare_database(state) do
+    :ok = mix(state, ["ecto.drop", "--quiet"])
+    :ok = mix(state, ["ecto.create", "--quiet"])
+    :ok = mix(state, ["ecto.migrate", "--quiet"])
   end
 
   defp ensure_app_dir! do
@@ -148,51 +196,52 @@ defmodule Livebook.EnterpriseServer do
     System.get_env("ENTERPRISE_PORT", "4043")
   end
 
-  defp debug? do
+  defp debug do
     System.get_env("ENTERPRISE_DEBUG", "false")
   end
 
-  defp wait_on_start(port) do
+  defp wait_on_start(state, port) do
-    case :httpc.request(:get, {~c"#{url()}/public/health", []}, [], []) do
+    url = state.url || fetch_url(state)
+
+    case :httpc.request(:get, {~c"#{url}/public/health", []}, [], []) do
       {:ok, _} ->
         port
 
       {:error, _} ->
         Process.sleep(10)
-        wait_on_start(port)
+        wait_on_start(state, port)
     end
   end
 
-  defp mix(args, opts \\ []) do
+  defp mix(state, args) do
-    env = [
+    cmd_opts = [
-      {"MIX_ENV", "livebook"},
+      stderr_to_stdout: true,
-      {"LIVEBOOK_ENTERPRISE_PORT", app_port()},
+      env: env(state),
-      {"LIVEBOOK_ENTERPRISE_DEBUG", debug?()}
+      cd: app_dir(),
+      into: IO.stream(:stdio, :line)
     ]
 
-    cmd_opts = [stderr_to_stdout: true, env: env, cd: app_dir()]
     args = ["--erl", "-elixir ansi_enabled true", "-S", "mix" | args]
 
-    cmd_opts =
+    case System.cmd(elixir_executable(), args, cmd_opts) do
-      if opts[:with_return],
+      {_, 0} -> :ok
-        do: cmd_opts,
+      _ -> :error
-        else: Keyword.put(cmd_opts, :into, IO.stream(:stdio, :line))
+    end
+  end
 
-    if opts[:with_return] do
+  defp env(state) do
-      case System.cmd(elixir_executable(), args, cmd_opts) do
+    app_port = state.app_port || app_port()
-        {result, 0} ->
-          result
 
-        {message, status} ->
+    env = %{
-          error("""
+      "MIX_ENV" => "livebook",
+      "LIVEBOOK_ENTERPRISE_PORT" => to_string(app_port),
+      "LIVEBOOK_ENTERPRISE_DEBUG" => debug()
+    }
 
-          #{message}\
+    if state.env do
-          """)
+      Map.merge(env, state.env)
-
-          System.halt(status)
-      end
     else
-      {_, 0} = System.cmd(elixir_executable(), args, cmd_opts)
+      env
     end
   end