From 354aae946747e276cc4f30367274f7d008edd2a0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@dashbit.co>
Date: Tue, 5 Oct 2021 00:49:01 +0200
Subject: [PATCH] Encapsulate compile and runtime configuration (#577)

---
 config/runtime.exs | 41 +-----------------------------------
 lib/livebook.ex    | 52 ++++++++++++++++++++++++++++++++++++++++++++++
 mix.exs            |  3 ++-
 3 files changed, 55 insertions(+), 41 deletions(-)

diff --git a/config/runtime.exs b/config/runtime.exs
index 0d3158270..249a9e82e 100644
--- a/config/runtime.exs
+++ b/config/runtime.exs
@@ -1,41 +1,2 @@
 import Config
-require Logger
-
-config :livebook, LivebookWeb.Endpoint,
-  secret_key_base:
-    Livebook.Config.secret!("LIVEBOOK_SECRET_KEY_BASE") ||
-      Base.encode64(:crypto.strong_rand_bytes(48))
-
-if password = Livebook.Config.password!("LIVEBOOK_PASSWORD") do
-  config :livebook, authentication_mode: :password, password: password
-else
-  config :livebook, token: Livebook.Utils.random_id()
-end
-
-if port = Livebook.Config.port!("LIVEBOOK_PORT") do
-  config :livebook, LivebookWeb.Endpoint, http: [port: port]
-end
-
-if ip = Livebook.Config.ip!("LIVEBOOK_IP") do
-  config :livebook, LivebookWeb.Endpoint, http: [ip: ip]
-end
-
-config :livebook,
-       :cookie,
-       Livebook.Config.cookie!("LIVEBOOK_COOKIE") ||
-         Livebook.Config.cookie!("RELEASE_COOKIE") ||
-         Livebook.Utils.random_cookie()
-
-config :livebook,
-       :default_runtime,
-       Livebook.Config.default_runtime!("LIVEBOOK_DEFAULT_RUNTIME") ||
-         {Livebook.Runtime.ElixirStandalone, []}
-
-root_path =
-  Livebook.Config.root_path!("LIVEBOOK_ROOT_PATH")
-  |> Livebook.FileSystem.Utils.ensure_dir_path()
-
-local_file_system = Livebook.FileSystem.Local.new(default_path: root_path)
-configured_file_systems = Livebook.Config.file_systems!("LIVEBOOK_FILE_SYSTEM_")
-
-config :livebook, :file_systems, [local_file_system | configured_file_systems]
+Livebook.config_runtime()
diff --git a/lib/livebook.ex b/lib/livebook.ex
index 4589f5780..f77ec0e29 100644
--- a/lib/livebook.ex
+++ b/lib/livebook.ex
@@ -5,6 +5,58 @@ defmodule Livebook do
   This module includes the public API.
   """
 
+  @doc """
+  Executes Livebook's config/runtime.exs.
+
+  If you use Livebook as a dependency, you can add the following
+  to your `config/runtime.exs` to trigger Livebook's config/runtime.exs
+  configuration:
+
+      Livebook.config_runtime()
+
+  """
+  def config_runtime do
+    import Config
+
+    config :livebook, LivebookWeb.Endpoint,
+      secret_key_base:
+        Livebook.Config.secret!("LIVEBOOK_SECRET_KEY_BASE") ||
+          Base.encode64(:crypto.strong_rand_bytes(48))
+
+    if port = Livebook.Config.port!("LIVEBOOK_PORT") do
+      config :livebook, LivebookWeb.Endpoint, http: [port: port]
+    end
+
+    if ip = Livebook.Config.ip!("LIVEBOOK_IP") do
+      config :livebook, LivebookWeb.Endpoint, http: [ip: ip]
+    end
+
+    if password = Livebook.Config.password!("LIVEBOOK_PASSWORD") do
+      config :livebook, authentication_mode: :password, password: password
+    else
+      config :livebook, token: Livebook.Utils.random_id()
+    end
+
+    if runtime = Livebook.Config.default_runtime!("LIVEBOOK_DEFAULT_RUNTIME") do
+      config :livebook, :default_runtime, runtime
+    end
+
+    config :livebook,
+           :cookie,
+           Livebook.Config.cookie!("LIVEBOOK_COOKIE") ||
+             Livebook.Config.cookie!("RELEASE_COOKIE") ||
+             Livebook.Utils.random_cookie()
+
+    root_path =
+      Livebook.Config.root_path!("LIVEBOOK_ROOT_PATH")
+      |> Livebook.FileSystem.Utils.ensure_dir_path()
+
+    local_file_system = Livebook.FileSystem.Local.new(default_path: root_path)
+    configured_file_systems = Livebook.Config.file_systems!("LIVEBOOK_FILE_SYSTEM_")
+
+    config :livebook, :file_systems, [local_file_system | configured_file_systems]
+  end
+
   @doc """
   Parses the given Live Markdown document and converts it to Elixir
   source code.
diff --git a/mix.exs b/mix.exs
index fde3821dd..db3f7ae86 100644
--- a/mix.exs
+++ b/mix.exs
@@ -24,7 +24,8 @@ defmodule Livebook.MixProject do
   def application do
     [
       mod: {Livebook.Application, []},
-      extra_applications: [:logger, :runtime_tools, :os_mon, :inets, :ssl, :xmerl]
+      extra_applications: [:logger, :runtime_tools, :os_mon, :inets, :ssl, :xmerl],
+      env: Application.get_all_env(:livebook)
     ]
   end