Improve error handling for color extraction

Includes a around embedding generation, which was happening twice (the
first call was redundant as record embeddings are always regenerated
after their parent artist embeddings are regenerated).

Closes #144.

lib/music_library/records.ex

@@ -3,6 +3,8 @@ defmodule MusicLibrary.Records do
   Provides function to work with records _irrespectively_ of their status as port of the collection or of the wishlist.
   """
 
+  require Logger
+
   import Ecto.Query, warn: false
 
   alias MusicLibrary.Artists
@@ -303,15 +305,28 @@ defmodule MusicLibrary.Records do
     enqueue_worker(Worker.RefreshCover, %{"id" => record.id}, record_meta(record))
   end
 
+  defp best_effort_extract_colors(record) do
+    case maybe_extract_colors(record) do
+      {:ok, record} ->
+        record
+
+      {:error, reason} ->
+        Logger.warning("Color extraction failed for record #{record.id}: #{inspect(reason)}")
+        record
+    end
+  end
+
   defp maybe_extract_colors(%{dominant_colors: [_ | _]} = record), do: {:ok, record}
   defp maybe_extract_colors(record), do: extract_colors(record)
 
   @spec extract_colors(Record.t()) :: {:ok, Record.t()} | {:error, term()}
   def extract_colors(record) do
-    asset = Assets.get!(record.cover_hash)
+    with asset when not is_nil(asset) <- Assets.get(record.cover_hash),
-
+         {:ok, colors} <- @color_extractor.extract_dominant_colors(asset.content) do
-    with {:ok, colors} <- @color_extractor.extract_dominant_colors(asset.content) do
       update_record(record, %{dominant_colors: colors})
+    else
+      nil -> {:error, :asset_not_found}
+      error -> error
     end
   end
 
@@ -392,10 +407,8 @@ defmodule MusicLibrary.Records do
   @spec create_record(map()) :: {:ok, Record.t()} | {:error, Ecto.Changeset.t()}
   def create_record(attrs \\ %{}) do
     with {:ok, record} <- do_create_record(attrs) do
-      {:ok, record} = maybe_extract_colors(record)
-      generate_embedding_async(record)
-
       record
+      |> best_effort_extract_colors()
       |> Record.artist_ids()
       |> Enum.each(fn artist_id ->
         Artists.refresh_artist_info_async(artist_id)

lib/music_library_web/error_messages.ex

@@ -21,6 +21,7 @@ defmodule MusicLibraryWeb.ErrorMessages do
     do: gettext("this record is already in your collection")
 
   def friendly_message(:not_found), do: gettext("the resource was not found")
+  def friendly_message(:asset_not_found), do: gettext("the cover image asset was not found")
   def friendly_message(:no_discogs_data), do: gettext("no Discogs profile available")
   def friendly_message(:image_not_found), do: gettext("no image could be found")
   def friendly_message(:invalid_parameters), do: gettext("invalid parameters were provided")

priv/gettext/default.pot

@@ -2375,3 +2375,8 @@ msgstr ""
 #, elixir-autogen, elixir-format
 msgid "Scan a record"
 msgstr ""
+
+#: lib/music_library_web/error_messages.ex
+#, elixir-autogen, elixir-format
+msgid "the cover image asset was not found"
+msgstr ""

priv/gettext/en/LC_MESSAGES/default.po

@@ -2375,3 +2375,8 @@ msgstr ""
 #, elixir-autogen, elixir-format
 msgid "Scan a record"
 msgstr ""
+
+#: lib/music_library_web/error_messages.ex
+#, elixir-autogen, elixir-format
+msgid "the cover image asset was not found"
+msgstr ""

test/music_library/records_test.exs

@@ -51,6 +51,13 @@ defmodule MusicLibrary.RecordsTest do
       assert Enum.all?(record.dominant_colors, &color_hex?/1)
     end
 
+    @tag :capture_log
+    test "succeeds when color extraction fails" do
+      record = record(dominant_colors: [], cover_hash: "nonexistent_hash")
+
+      assert record.dominant_colors == []
+    end
+
     test "queues a task to retrieve artist info data" do
       record =
         record(musicbrainz_data: release_group(:lockdown_trilogy))