Validate status code for all service instances

Updated to filter out all instances that either time out (I believe
default timeout for HTTPoison is 5s) or return a non-200 status code.

update.exs

@@ -1,19 +1,31 @@
 defmodule Instance do
   defstruct [
     instance_type: nil,
+    instance_test: nil,
     instance_list: []
   ]
 end
 
 defmodule Instances do
+  def request(url) do
+    case HTTPoison.get(url) do
+      {:ok, %HTTPoison.Response{status_code: 200}} ->
+        # TODO: Add validation of results, not just status code
+        :good
+      _ ->
+        :bad
+    end
+  end
+
   def update(filename) do
     {:ok, file} = File.read(filename)
     {:ok, json} = Poison.decode(file, as: [%Instance{}])
-    for x <- json do
-      IO.puts(x.instance_type)
-      for y <- x.instance_list do
-        IO.puts(" - " <> y)
-      end
+    for service <- json do
+      result = Enum.filter(service.instance_list, fn(url) ->
+        request(url <> service.instance_test) == :good
+      end)
+      # TODO: Output result to redis
+      IO.inspect(result)
     end
   end
 end