Include default secret key base and cookie in apps Dockerfile

README.md

@@ -340,7 +340,7 @@ When clustering is enabled, you must additionally set the following env vars:
   * `LIVEBOOK_NODE=livebook_server@IP`, where `IP` is the machine IP of each
     deployed node
 
-  * You must set `LIVEBOOK_SECRET_KEY_BASE` and `RELEASE_COOKIE` to
+  * You must set `LIVEBOOK_SECRET_KEY_BASE` and `LIVEBOOK_COOKIE` to
     different random values (use `openssl rand -base64 48` to generate
     said values)
 

lib/livebook.ex

@@ -89,7 +89,7 @@ defmodule Livebook do
     config :livebook, LivebookWeb.Endpoint,
       secret_key_base:
         Livebook.Config.secret!("LIVEBOOK_SECRET_KEY_BASE") ||
-          Base.encode64(:crypto.strong_rand_bytes(48))
+          Livebook.Utils.random_secret_key_base()
 
     if Livebook.Config.debug!("LIVEBOOK_DEBUG") do
       config :logger, level: :debug

lib/livebook/hubs/dockerfile.ex

@@ -116,20 +116,31 @@ defmodule Livebook.Hubs.Dockerfile do
     RUN /app/bin/warmup_apps.sh
     """
 
+    random_secret_key_base = Livebook.Utils.random_secret_key_base()
+    random_cookie = Livebook.Utils.random_cookie()
+
     startup =
       if config.clustering == :fly_io do
-        ~S"""
-        # Custom startup script to cluster multiple Livebook nodes on Fly.io
-        RUN printf '\
-        #!/bin/bash\n\
-        export ERL_AFLAGS="-proto_dist inet6_tcp"\n\
-        export LIVEBOOK_NODE="${FLY_APP_NAME}-${FLY_IMAGE_REF##*-}@${FLY_PRIVATE_IP}"\n\
-        export LIVEBOOK_CLUSTER="dns:${FLY_APP_NAME}.internal"\n\
-        /app/bin/livebook start\n\
-        ' > /app/bin/start.sh && chmod +x /app/bin/start.sh
-
-        CMD [ "/app/bin/start.sh" ]
         """
+        # --- Clustering ---
+
+        # Set the same Livebook secrets across all nodes
+        ENV LIVEBOOK_SECRET_KEY_BASE "#{random_secret_key_base}"
+        ENV LIVEBOOK_COOKIE "#{random_cookie}"
+
+        """ <>
+          ~S"""
+          # Custom startup script to cluster multiple Livebook nodes on Fly.io
+          RUN printf '\
+          #!/bin/bash\n\
+          export ERL_AFLAGS="-proto_dist inet6_tcp"\n\
+          export LIVEBOOK_NODE="${FLY_APP_NAME}-${FLY_IMAGE_REF##*-}@${FLY_PRIVATE_IP}"\n\
+          export LIVEBOOK_CLUSTER="dns:${FLY_APP_NAME}.internal"\n\
+          /app/bin/livebook start\n\
+          ' > /app/bin/start.sh && chmod +x /app/bin/start.sh
+
+          CMD [ "sh", "-c", "/app/bin/start.sh" ]
+          """
       end
 
     [

lib/livebook/utils.ex

@@ -27,6 +27,14 @@ defmodule Livebook.Utils do
     :"c_#{Base.url_encode64(:crypto.strong_rand_bytes(39))}"
   end
 
+  @doc """
+  Generates a random value for Phoenix secret key base.
+  """
+  @spec random_secret_key_base() :: String.t()
+  def random_secret_key_base() do
+    Base.encode64(:crypto.strong_rand_bytes(48))
+  end
+
   @doc """
   Generates a random binary id that includes node information.
 

lib/livebook_web/live/app_helpers.ex

@@ -178,6 +178,7 @@ defmodule LivebookWeb.AppHelpers do
   """
   attr :hub, :map, required: true
   attr :dockerfile, :string, required: true
+  attr :dockerfile_config, :map, required: true
 
   slot :dockerfile_actions, default: nil
 
@@ -235,6 +236,16 @@ defmodule LivebookWeb.AppHelpers do
             platform
           </span>
         </li>
+        <li :if={@dockerfile_config.clustering} class="flex gap-2">
+          <div><.remix_icon icon="arrow-right-line" class="text-gray-900" /></div>
+          <span>
+            you may set <code>LIVEBOOK_SECRET_KEY_BASE</code>
+            and <code>LIVEBOOK_COOKIE</code>
+            as runtime environment secrets in your deployment platform, to ensure their
+            values stay the same across deployments. If you do that, you can remove
+            the defaults from your Dockerfile
+          </span>
+        </li>
         <li class="flex gap-2">
           <div><.remix_icon icon="arrow-right-line" class="text-gray-900" /></div>
           <span>

lib/livebook_web/live/hub/edit/team_component.ex

@@ -220,7 +220,11 @@ defmodule LivebookWeb.Hub.Edit.TeamComponent do
                 />
               </.form>
 
-              <LivebookWeb.AppHelpers.docker_instructions hub={@hub} dockerfile={@dockerfile} />
+              <LivebookWeb.AppHelpers.docker_instructions
+                hub={@hub}
+                dockerfile={@dockerfile}
+                dockerfile_config={Ecto.Changeset.apply_changes(@config_changeset)}
+              />
             </div>
 
             <div class="flex flex-col space-y-4">

lib/livebook_web/live/session_live/app_docker_component.ex

@@ -96,7 +96,11 @@ defmodule LivebookWeb.SessionLive.AppDockerComponent do
         <AppHelpers.docker_config_form_content hub={@hub} form={f} />
       </.form>
       <.save_result :if={@save_result} save_result={@save_result} />
-      <AppHelpers.docker_instructions hub={@hub} dockerfile={@dockerfile}>
+      <AppHelpers.docker_instructions
+        hub={@hub}
+        dockerfile={@dockerfile}
+        dockerfile_config={apply_changes(@changeset)}
+      >
         <:dockerfile_actions>
           <button
             class="button-base button-gray whitespace-nowrap py-1 px-2"

rel/server/env.bat.eex

@@ -4,6 +4,7 @@ if not defined RELEASE_NODE set RELEASE_NODE=livebook_server
 if defined LIVEBOOK_DISTRIBUTION set RELEASE_DISTRIBUTION="!LIVEBOOK_DISTRIBUTION!"
 if not defined RELEASE_DISTRIBUTION (if defined LIVEBOOK_CLUSTER set RELEASE_DISTRIBUTION="name")
 
+if defined LIVEBOOK_COOKIE set RELEASE_COOKIE="!LIVEBOOK_COOKIE!"
 set cookie_path="!RELEASE_ROOT!\releases\COOKIE"
 if not exist %cookie_path% (
   if not defined RELEASE_COOKIE (

rel/server/env.sh.eex

@@ -1,8 +1,9 @@
 export RELEASE_MODE=interactive
 export RELEASE_NODE=${LIVEBOOK_NODE:-${RELEASE_NODE:-livebook_server}}
-if [[ -z "${LIVEBOOK_CLUSTER}" ]]; then DISTRIBUTION_DEFAULT="sname"; else DISTRIBUTION_DEFAULT="name"; fi
+if [ -z "${LIVEBOOK_CLUSTER}" ]; then DISTRIBUTION_DEFAULT="sname"; else DISTRIBUTION_DEFAULT="name"; fi
 export RELEASE_DISTRIBUTION=${LIVEBOOK_DISTRIBUTION:-${RELEASE_DISTRIBUTION:-${DISTRIBUTION_DEFAULT}}}
 
+if [ ! -z "${LIVEBOOK_COOKIE}" ]; then export RELEASE_COOKIE=${LIVEBOOK_COOKIE}; fi
 cookie_path="${RELEASE_ROOT}/releases/COOKIE"
 if [ ! -f $cookie_path ] && [ -z "$RELEASE_COOKIE" ]; then
   RELEASE_COOKIE=$(cat /dev/urandom | env LC_ALL=C tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1)