Support ecto config

README.md

@@ -97,16 +97,18 @@ defmodule MySystem.Repo do
     adapter: Ecto.Adapters.Postgres
 
   @impl Ecto.Repo
-  def init(_type, config) do
-    {:ok,
-      Keyword.merge(
-        config,
-        hostname: MySystem.Config.db_host(),
-        database_name: MySystem.Config.db_name(),
-        pool_size: MySystem.Config.db_pool_size(),
-        # ...
-      )
-    }
+  def init(context, config) do
+    Provider.ecto_config(MySystem.Config, context, fn ->
+      {:ok,
+        Keyword.merge(
+          config,
+          hostname: MySystem.Config.db_host(),
+          database_name: MySystem.Config.db_name(),
+          pool_size: MySystem.Config.db_pool_size(),
+          # ...
+        )
+      }
+    end)
   end
 end
 ```

lib/provider.ex

@@ -102,6 +102,7 @@ defmodule Provider do
   @type type :: :string | :integer | :float | :boolean
   @type value :: String.t() | number | boolean | nil
   @type data :: %{param_name => value}
+  @type ecto_context :: :supervisor | :runtime
 
   # ------------------------------------------------------------------------
   # API
@@ -129,6 +130,19 @@ defmodule Provider do
     end
   end
 
+  @spec ecto_config(module(), ecto_context(), (-> {:ok, Keyword.t()})) :: {:ok, Keyword.t()}
+  def ecto_config(mod, context, fun) do
+    mod.start_link(nil)
+
+    ret = fun.()
+
+    if context == :runtime do
+      GenServer.stop(mod)
+    end
+
+    ret
+  end
+
   # ------------------------------------------------------------------------
   # Private
   # ------------------------------------------------------------------------

mix.exs

@@ -1,7 +1,7 @@
 defmodule Provider.MixProject do
   use Mix.Project
 
-  @version "0.2.0"
+  @version "0.2.1"
 
   def project do
     [

test/provider_test.exs

@@ -37,6 +37,48 @@ defmodule ProviderTest do
     end
   end
 
+  describe "ecto_config" do
+    test "starts and stops the server when the context is :runtime" do
+      System.put_env("OPT_1", "some data")
+      System.put_env("OPT_2", "42")
+      System.put_env("OPT_6", "false")
+      System.put_env("OPT_7", "3.14")
+
+      pid = Process.whereis(TestModule)
+      assert is_nil(pid)
+
+      config =
+        Provider.ecto_config(TestModule, :runtime, fn ->
+          {:ok, [hostname: TestModule.opt_1()]}
+        end)
+
+      assert {:ok, [hostname: "some data"]} = config
+
+      pid = Process.whereis(TestModule)
+      assert is_nil(pid)
+    end
+
+    test "starts but not stops the server when the context is :supervisor" do
+      System.put_env("OPT_1", "some data")
+      System.put_env("OPT_2", "42")
+      System.put_env("OPT_6", "false")
+      System.put_env("OPT_7", "3.14")
+
+      pid = Process.whereis(TestModule)
+      assert is_nil(pid)
+
+      config =
+        Provider.ecto_config(TestModule, :supervisor, fn ->
+          {:ok, [hostname: TestModule.opt_1()]}
+        end)
+
+      assert {:ok, [hostname: "some data"]} = config
+
+      pid = Process.whereis(TestModule)
+      assert not is_nil(pid)
+    end
+  end
+
   describe "generated module" do
     setup do
       Enum.each(1..7, &System.delete_env("OPT_#{&1}"))