[refs #16] logs loading errors during startup/reload

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## v0.14.0-dev
+
+- Enhancements
+    - Errors occurring while initially loading databases
+      (or when calling `Geolix.reload_databases/0`) are now sent to
+      `Logger.error` ([#16](https://github.com/elixir-geolix/geolix/issues/16))
+
 ## v0.13.0 (2017-04-12)
 
 - Backwards incompatible changes

lib/geolix/database/loader.ex

@@ -5,6 +5,8 @@ defmodule Geolix.Database.Loader do
 
   use GenServer
 
+  require Logger
+
   alias Geolix.Database.Supervisor, as: DatabaseSupervisor
 
 
@@ -44,7 +46,18 @@ defmodule Geolix.Database.Loader do
   end
 
   def handle_cast(:reload_databases, state) do
-    :ok = state |> Keyword.values() |> Enum.each(&load_database/1)
+    :ok =
+      state
+      |> Keyword.values()
+      |> Enum.each(fn (db) ->
+           case load_database(db) do
+             :ok               -> :ok
+             { :error, error } ->
+               Logger.error "Failed to load database" <>
+                            " #{ inspect(db[:id]) }:" <>
+                            " #{ inspect(error) }"
+           end
+         end)
 
     { :noreply, state }
   end

test/geolix/database/loader_error_test.exs

@@ -0,0 +1,47 @@
+defmodule Geolix.Database.LoaderErrorTest do
+  use ExUnit.Case, async: false
+
+  import ExUnit.CaptureLog
+
+  alias Geolix.Adapter.MMDB2
+  alias Geolix.Database.Supervisor, as: DatabaseSupervisor
+
+
+  setup do
+    databases = Application.get_env(:geolix, :databases)
+
+    on_exit fn ->
+      :ok = Application.put_env(:geolix, :databases, databases)
+    end
+  end
+
+  defp restart_supervisor() do
+    true =
+      DatabaseSupervisor
+      |> Process.whereis()
+      |> Process.exit(:kill)
+
+    :timer.sleep(250)
+
+    :ok
+  end
+
+
+  test "(re-) loading databases at startup logs errors" do
+    id = :initially_broken
+    db = %{
+      id:      id,
+      adapter: MMDB2,
+      source:  Path.join([ __DIR__, "does-not-exist" ])
+    }
+
+    assert capture_log(fn ->
+      :ok = Application.put_env(:geolix, :databases, [ db ])
+      :ok = restart_supervisor()
+      :ok = Geolix.reload_databases()
+
+      # ensure GenServer.cast/1 was processed
+      :timer.sleep(100)
+    end) =~ "does not exist"
+  end
+end