fix(workers): snooze incoming jobs while a host is backed off

With 5 attempts and Oban's short retry delays, an incoming activity from
an unknown actor on a backed-off host was discarded without a request.
ReceiverWorker and SignatureRetryWorker now snooze for up to 2 hours.
Also lowercase backoff host keys and log backed-off user fetches at debug.

test/pleroma/http/backoff_test.exs

@@ -67,6 +67,15 @@ defmodule Pleroma.HTTP.BackoffTest do
       assert_ttl_about(300)
     end
 
+    test "treats host names case-insensitively" do
+      mock_response(429)
+      assert {:error, :ratelimit} = Backoff.get("https://RateLimited.Example.com/users/alice")
+      assert_received :request
+
+      assert {:error, :ratelimit} = Backoff.get(@url)
+      refute_received :request
+    end
+
     test "only backs off from the host that answered" do
       mock_response(429)
       assert {:error, :ratelimit} = Backoff.get(@url)

test/pleroma/web/web_finger_test.exs

@@ -308,6 +308,7 @@ defmodule Pleroma.Web.WebFingerTest do
 
   describe "rate limiting" do
     setup do
+      # the module setup stubs NullCache, the backoff needs a real cache
       Mox.stub_with(Pleroma.CachexMock, Pleroma.CachexProxy)
       test_pid = self()
 

test/pleroma/workers/receiver_worker_test.exs

@@ -133,6 +133,28 @@ defmodule Pleroma.Workers.ReceiverWorkerTest do
     end
   end
 
+  describe "rate-limited fetches" do
+    setup do
+      Cachex.put(:http_backoff_cache, "ratelimited.example", true)
+
+      params =
+        insert(:note_activity).data
+        |> Map.put("actor", "https://ratelimited.example/users/alice")
+
+      %{args: %{"op" => "incoming_ap_doc", "params" => params}}
+    end
+
+    test "snooze while the actor's host is backed off", %{args: args} do
+      assert {:snooze, 300} = perform_job(ReceiverWorker, args)
+    end
+
+    test "stop snoozing two hours after the job was inserted", %{args: args} do
+      inserted_at = DateTime.add(DateTime.utc_now(), -121, :minute)
+
+      assert {:error, :ratelimit} = perform_job(ReceiverWorker, args, inserted_at: inserted_at)
+    end
+  end
+
   test "cancels due to origin containment" do
     params =
       insert(:note_activity).data

test/pleroma/workers/signature_retry_worker_test.exs

@@ -306,6 +306,24 @@ defmodule Pleroma.Workers.SignatureRetryWorkerTest do
     refute Activity.get_by_ap_id(create["id"])
   end
 
+  test "snoozes while the payload actor's host is backed off" do
+    Cachex.put(:http_backoff_cache, "ratelimited.example", true)
+    alice = build(:user, local: false, ap_id: "https://ratelimited.example/users/alice")
+
+    params = %{
+      "type" => "Create",
+      "actor" => alice.ap_id,
+      "id" => "https://ratelimited.example/activities/1",
+      "object" => "https://ratelimited.example/objects/1"
+    }
+
+    job = failed_signature_job(params, signature_headers_for(alice))
+    assert {:snooze, 300} = SignatureRetryWorker.perform(job)
+
+    old_job = %{job | inserted_at: DateTime.add(DateTime.utc_now(), -121, :minute)}
+    assert {:error, :ratelimit} = SignatureRetryWorker.perform(old_job)
+  end
+
   test "processes the activity after refetching a valid matching signature" do
     alice = insert(:user, local: false, ap_id: "https://one.com/users/alice")