Don't try to cleanup remote attachments

The cleanup attachment worker was run for every deleted post,
even if it’s a remote post whose attachments we don't even store.
This was especially bad due to attachment cleanup involving a
particularly heavy query wasting a bunch of database perf for nil.

This was uncovered by comparing statistics from
AkkomaGang/akkoma#784 and
AkkomaGang/akkoma#765 (comment)

lib/pleroma/object.ex

@@ -9,7 +9,6 @@ defmodule Pleroma.Object do
   import Ecto.Changeset
 
   alias Pleroma.Activity
-  alias Pleroma.Config
   alias Pleroma.Hashtag
   alias Pleroma.Object
   alias Pleroma.Object.Fetcher
@@ -241,23 +240,11 @@ def delete(%Object{data: %{"id" => id}} = object) do
     with {:ok, _obj} = swap_object_with_tombstone(object),
          deleted_activity = Activity.delete_all_by_object_ap_id(id),
          {:ok, _} <- invalid_object_cache(object) do
-      cleanup_attachments(
-        Config.get([:instance, :cleanup_attachments]),
-        %{object: object}
-      )
-
+      AttachmentsCleanupWorker.enqueue_if_needed(object.data)
       {:ok, object, deleted_activity}
     end
   end
 
-  @spec cleanup_attachments(boolean(), %{required(:object) => map()}) ::
-          {:ok, Oban.Job.t() | nil}
-  def cleanup_attachments(true, %{object: _} = params) do
-    AttachmentsCleanupWorker.enqueue("cleanup_attachments", params)
-  end
-
-  def cleanup_attachments(_, _), do: {:ok, nil}
-
   def prune(%Object{data: %{"id" => _id}} = object) do
     with {:ok, object} <- Repo.delete(object),
          {:ok, _} <- invalid_object_cache(object) do

lib/pleroma/workers/attachments_cleanup_worker.ex

@@ -5,30 +5,61 @@
 defmodule Pleroma.Workers.AttachmentsCleanupWorker do
   import Ecto.Query
 
+  alias Pleroma.Config
   alias Pleroma.Object
   alias Pleroma.Repo
 
   use Pleroma.Workers.WorkerHelper, queue: "attachments_cleanup"
 
+  @doc """
+  Takes object data and if necessary enqueues a job,
+  deleting all attachments of the post eligible for cleanup
+  """
+  @spec enqueue_if_needed(map()) :: {:ok, Oban.Job.t()} | {:ok, :skip} | {:error, any()}
+  def enqueue_if_needed(%{
+        "actor" => actor,
+        "attachment" => [_ | _] = attachments
+      }) do
+    with true <- Config.get([:instance, :cleanup_attachments]),
+         true <- URI.parse(actor).host == Pleroma.Web.Endpoint.host(),
+         [_ | _] <- attachments do
+      enqueue("cleanup_attachments", %{"actor" => actor, "attachments" => attachments})
+    else
+      _ -> {:ok, :skip}
+    end
+  end
+
+  def enqueue_if_needed(_), do: {:ok, :skip}
+
   @impl Oban.Worker
   def perform(%Job{
         args: %{
           "op" => "cleanup_attachments",
-          "object" => %{"data" => %{"attachment" => [_ | _] = attachments, "actor" => actor}}
+          "attachments" => [_ | _] = attachments,
+          "actor" => actor
         }
       }) do
-    if Pleroma.Config.get([:instance, :cleanup_attachments], false) do
-      attachments
-      |> Enum.flat_map(fn item -> Enum.map(item["url"], & &1["href"]) end)
-      |> fetch_objects
-      |> prepare_objects(actor, Enum.map(attachments, & &1["name"]))
-      |> filter_objects
-      |> do_clean
-    end
+    attachments
+    |> Enum.flat_map(fn item -> Enum.map(item["url"], & &1["href"]) end)
+    |> fetch_objects
+    |> prepare_objects(actor, Enum.map(attachments, & &1["name"]))
+    |> filter_objects
+    |> do_clean
 
     {:ok, :success}
   end
 
+  # Left over already enqueued jobs in the old format
+  # This function clause can be deleted once sufficient time passed after 3.14
+  def perform(%Job{
+        args: %{
+          "op" => "cleanup_attachments",
+          "object" => %{"data" => data}
+        }
+      }) do
+    enqueue_if_needed(data)
+  end
+
   def perform(%Job{args: %{"op" => "cleanup_attachments", "object" => _object}}), do: {:ok, :skip}
 
   defp do_clean({object_ids, attachment_urls}) do

test/pleroma/workers/attachments_cleanup_worker_test.exs

@@ -0,0 +1,60 @@
+# Akkoma: Magically expressive social media
+# Copyright © 2024 Akkoma Authors <https://akkoma.dev/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Workers.AttachmentsCleanupWorkerTest do
+  use Pleroma.DataCase, async: false
+  use Oban.Testing, repo: Pleroma.Repo
+
+  import Pleroma.Factory
+
+  alias Pleroma.Workers.AttachmentsCleanupWorker
+
+  setup do
+    clear_config([:instance, :cleanup_attachments], true)
+
+    file = %Plug.Upload{
+      content_type: "image/jpeg",
+      path: Path.absname("test/fixtures/image.jpg"),
+      filename: "an_image.jpg"
+    }
+
+    user = insert(:user)
+
+    {:ok, %Pleroma.Object{} = attachment} =
+      Pleroma.Web.ActivityPub.ActivityPub.upload(file, actor: user.ap_id)
+
+    {:ok, attachment: attachment, user: user}
+  end
+
+  test "does not enqueue remote post" do
+    remote_data = %{
+      "id" => "https://remote.example/obj/123",
+      "actor" => "https://remote.example/user/1",
+      "content" => "content",
+      "attachment" => [
+        %{
+          "type" => "Document",
+          "mediaType" => "image/png",
+          "name" => "marvellous image",
+          "url" => "https://remote.example/files/image.png"
+        }
+      ]
+    }
+
+    assert {:ok, :skip} = AttachmentsCleanupWorker.enqueue_if_needed(remote_data)
+  end
+
+  test "enqueues local post", %{attachment: attachment, user: user} do
+    local_url = Pleroma.Web.Endpoint.url()
+
+    local_data = %{
+      "id" => local_url <> "/obj/123",
+      "actor" => user.ap_id,
+      "content" => "content",
+      "attachment" => [attachment.data]
+    }
+
+    assert {:ok, %Oban.Job{}} = AttachmentsCleanupWorker.enqueue_if_needed(local_data)
+  end
+end