From 24c4ba90800206a422f082a8c0517a8bffa86e6d Mon Sep 17 00:00:00 2001
From: Pedro Tavares <pedro.tavares@talkdesk.com>
Date: Tue, 9 Jul 2019 16:33:13 +0100
Subject: [PATCH] Make Horde.Supervisor child_spec overridable

Fixes #107
---
 lib/horde/supervisor.ex                 |  8 ++++++--
 test/supervisor_test.exs                | 20 ++++++++++++++++++++
 test/support/module_based_supervisor.ex | 17 +++++++++++++++++
 3 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/lib/horde/supervisor.ex b/lib/horde/supervisor.ex
index 12cfa1ea..b43dbf0d 100644
--- a/lib/horde/supervisor.ex
+++ b/lib/horde/supervisor.ex
@@ -45,23 +45,27 @@ defmodule Horde.Supervisor do
   Then you can use `MySupervisor.child_spec/1` and `MySupervisor.start_link/1` in the same way as you'd use `Horde.Supervisor.child_spec/1` and `Horde.Supervisor.start_link/1`.
   """
 
-  defmacro __using__(_opts) do
+  defmacro __using__(opts) do
     quote do
       @behaviour Horde.Supervisor
 
       def child_spec(options) do
         options = Keyword.put_new(options, :id, __MODULE__)
 
-        %{
+        default = %{
           id: Keyword.get(options, :id, __MODULE__),
           start: {__MODULE__, :start_link, [options]},
           type: :supervisor
         }
+
+        Supervisor.child_spec(default, unquote(Macro.escape(opts)))
       end
 
       def start_link(options) do
         Horde.Supervisor.start_link(Keyword.put(options, :init_module, __MODULE__))
       end
+
+      defoverridable child_spec: 1
     end
   end
 
diff --git a/test/supervisor_test.exs b/test/supervisor_test.exs
index d9691175..0ee84db3 100644
--- a/test/supervisor_test.exs
+++ b/test/supervisor_test.exs
@@ -89,6 +89,26 @@ defmodule SupervisorTest do
       {:ok, members} = Horde.Cluster.members(:init_sup_test_1)
       assert 2 = Enum.count(members)
     end
+
+    test "can use `child_spec` function to override defaults from Horde.Supervisor" do
+      assert %{
+               id: 123,
+               start:
+                 {TestSupervisor3, :start_link,
+                  [
+                    custom_id: 123,
+                    name: :init_sup_test_3,
+                    strategy: :one_for_one
+                  ]},
+               restart: :transient,
+               type: :supervisor
+             } =
+               TestSupervisor3.child_spec(
+                 custom_id: 123,
+                 name: :init_sup_test_3,
+                 strategy: :one_for_one
+               )
+    end
   end
 
   describe ".start_child/2" do
diff --git a/test/support/module_based_supervisor.ex b/test/support/module_based_supervisor.ex
index 75f89378..46a70713 100644
--- a/test/support/module_based_supervisor.ex
+++ b/test/support/module_based_supervisor.ex
@@ -13,3 +13,20 @@ defmodule TestSupervisor2 do
     {:ok, Keyword.put(options, :members, [:init_sup_test_1, :init_sup_test_2])}
   end
 end
+
+defmodule TestSupervisor3 do
+  use Horde.Supervisor
+
+  def init(options) do
+    {:ok, Keyword.put(options, :members, [:init_sup_test_3, :init_sup_test_3])}
+  end
+
+  def child_spec(args) do
+    %{
+      id: args[:id],
+      start: {__MODULE__, :start_link, [args]},
+      restart: :transient,
+      type: :supervisor
+    }
+  end
+end