From f1ece34addec6191f40b79d10abec54fddb32466 Mon Sep 17 00:00:00 2001
From: Sky Rose <srose@mbta.com>
Date: Mon, 13 May 2024 16:56:51 -0400
Subject: [PATCH] /_health endpoint (#2)

---
 .../controllers/db_health_controller.ex         | 17 +++++++++++++++++
 lib/orbit_web/controllers/health_controller.ex  | 11 +++++++++++
 lib/orbit_web/router.ex                         |  9 +++++----
 .../controllers/health_controller_test.exs      |  8 ++++++++
 4 files changed, 41 insertions(+), 4 deletions(-)
 create mode 100644 lib/orbit_web/controllers/db_health_controller.ex
 create mode 100644 lib/orbit_web/controllers/health_controller.ex
 create mode 100644 test/orbit_web/controllers/health_controller_test.exs

diff --git a/lib/orbit_web/controllers/db_health_controller.ex b/lib/orbit_web/controllers/db_health_controller.ex
new file mode 100644
index 00000000..ee2f313a
--- /dev/null
+++ b/lib/orbit_web/controllers/db_health_controller.ex
@@ -0,0 +1,17 @@
+defmodule OrbitWeb.HealthDbController do
+  @moduledoc """
+  Controller that runs a database query to check whether the webserver can connect to the database.
+  """
+  use OrbitWeb, :controller
+  import Ecto.Query
+
+  alias Orbit.Repo
+
+  def index(conn, _params) do
+    count = Repo.one(from(migration in "schema_migrations", select: count(migration)))
+
+    conn
+    |> put_status(200)
+    |> text("#{count}")
+  end
+end
diff --git a/lib/orbit_web/controllers/health_controller.ex b/lib/orbit_web/controllers/health_controller.ex
new file mode 100644
index 00000000..d98025d0
--- /dev/null
+++ b/lib/orbit_web/controllers/health_controller.ex
@@ -0,0 +1,11 @@
+defmodule OrbitWeb.HealthController do
+  @moduledoc """
+  Simple controller to return 200 OK when the website is healthy.
+  """
+  use OrbitWeb, :controller
+
+  def index(conn, _params) do
+    conn
+    |> send_resp(200, "")
+  end
+end
diff --git a/lib/orbit_web/router.ex b/lib/orbit_web/router.ex
index 669c10af..f73ba2e2 100644
--- a/lib/orbit_web/router.ex
+++ b/lib/orbit_web/router.ex
@@ -20,10 +20,11 @@ defmodule OrbitWeb.Router do
     get "/", PageController, :home
   end
 
-  # Other scopes may use custom stacks.
-  # scope "/api", OrbitWeb do
-  #   pipe_through :api
-  # end
+  scope "/", OrbitWeb do
+    # no pipe
+    get "/_health", HealthController, :index
+    get "/_health_db", HealthDbController, :index
+  end
 
   # Enable LiveDashboard in development
   if Application.compile_env(:orbit, :dev_routes) do
diff --git a/test/orbit_web/controllers/health_controller_test.exs b/test/orbit_web/controllers/health_controller_test.exs
new file mode 100644
index 00000000..b5e64e0e
--- /dev/null
+++ b/test/orbit_web/controllers/health_controller_test.exs
@@ -0,0 +1,8 @@
+defmodule OrbitWeb.HealthControllerTest do
+  use OrbitWeb.ConnCase
+
+  test "GET /_health", %{conn: conn} do
+    conn = get(conn, ~p"/_health")
+    assert response(conn, 200)
+  end
+end