Add health check endpoint

lib/polar_web/endpoint.ex

@@ -15,6 +15,8 @@ defmodule PolarWeb.Endpoint do
     websocket: [connect_info: [session: @session_options]],
     longpoll: [connect_info: [session: @session_options]]
 
+  plug PolarWeb.Plugs.HealthCheck
+
   # Serve at "/" the static files from "priv/static" directory.
   #
   # You should set gzip to true if you are running phx.digest

lib/polar_web/plugs/health_check.ex

@@ -0,0 +1,18 @@
+defmodule PolarWeb.Plugs.HealthCheck do
+  import Plug.Conn
+
+  def init(opts), do: opts
+
+  def call(%Plug.Conn{request_path: "/health"} = conn, _opts) do
+    conn
+    |> send_resp(
+      200,
+      Jason.encode!(%{
+        status: "Polar serving images."
+      })
+    )
+    |> halt()
+  end
+
+  def call(conn, _opts), do: conn
+end