Track usage of media files and add a job to clean them

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/service/workers/clean_orphan_media_worker.ex

@@ -0,0 +1,31 @@
+defmodule Mobilizon.Service.Workers.CleanOrphanMediaWorker do
+  @moduledoc """
+  Worker to clean orphan media
+  """
+
+  use Oban.Worker, queue: "background"
+  alias Mobilizon.Service.CleanOrphanMedia
+
+  @grace_period Mobilizon.Config.get([:instance, :orphan_upload_grace_period_hours], 48)
+
+  @impl Oban.Worker
+  def perform(%Job{}) do
+    if Mobilizon.Config.get!([:instance, :remove_orphan_uploads]) and should_perform?() do
+      CleanOrphanMedia.clean()
+    end
+  end
+
+  @spec should_perform? :: boolean()
+  defp should_perform? do
+    case Cachex.get(:key_value, "last_media_cleanup") do
+      {:ok, %DateTime{} = last_media_cleanup} ->
+        DateTime.compare(
+          last_media_cleanup,
+          DateTime.add(DateTime.utc_now(), @grace_period * -3600)
+        ) == :lt
+
+      _ ->
+        true
+    end
+  end
+end