bugfix: Oban instance not available when named supervisors are used

lib/prom_ex/plugins/oban.ex

@@ -438,7 +438,7 @@ if Code.ensure_loaded?(Oban) do
 
       config
       |> Oban.Repo.all(query)
-      |> include_zeros_for_missing_queue_states()
+      |> include_zeros_for_missing_queue_states(config)
       |> Enum.each(fn {{queue, state}, count} ->
         measurements = %{count: count}
         metadata = %{name: normalize_module_name(oban_supervisor), queue: queue, state: state}
@@ -447,10 +447,10 @@ if Code.ensure_loaded?(Oban) do
       end)
     end
 
-    defp include_zeros_for_missing_queue_states(query_result) do
+    defp include_zeros_for_missing_queue_states(query_result, config) do
       {_, opts} =
-        Oban.config().plugins
-        |> Enum.find({nil, [queues: Oban.config().queues]}, fn {plugin, _} ->
+        config.plugins
+        |> Enum.find({nil, [queues: config.queues]}, fn {plugin, _} ->
           plugin == Oban.Pro.Plugins.DynamicQueues
         end)
 

test/prom_ex/plugins/oban_test.exs

@@ -14,6 +14,34 @@ defmodule PromEx.Plugins.ObanTest do
     end
   end
 
+  defmodule TestRepo do
+    def child_spec(_opts) do
+      %{
+        id: __MODULE__,
+        start: {__MODULE__, :start_link, []},
+        type: :supervisor
+      }
+    end
+
+    def start_link do
+      Agent.start_link(fn -> :ok end, name: __MODULE__)
+    end
+
+    def all(_query), do: []
+    def all(_query, _opts), do: []
+    def get_dynamic_repo, do: nil
+
+    # Required by Oban - provides repository configuration
+    def config do
+      [
+        otp_app: :prom_ex,
+        adapter: Ecto.Adapters.Postgres,
+        database: "test_db",
+        hostname: "localhost"
+      ]
+    end
+  end
+
   test "telemetry events are accumulated" do
     start_supervised!(WebApp.PromEx)
 
@@ -39,4 +67,54 @@ defmodule PromEx.Plugins.ObanTest do
       assert [] == ObanPlugin.manual_metrics([])
     end
   end
+
+  describe "Integration test - named supervisor" do
+    test "execute_queue_metrics uses config of named supervisor if Oban instance is not running" do
+      start_supervised!(TestRepo)
+
+      oban_config = [
+        # Named supervisor - this is key!
+        name: CustomApp.Jobs.Oban,
+        repo: TestRepo,
+        queues: [default: 10, high: 5],
+        plugins: [],
+        # Prevent automatic job processing
+        testing: :manual,
+        # Use a minimal notifier for testing
+        notifier: {Oban.Notifiers.PG, []},
+        # Use isolated peer for testing
+        peer: {Oban.Peers.Isolated, [leader?: false]}
+      ]
+
+      {:ok, _oban_pid} = start_supervised({Oban, oban_config})
+      :timer.sleep(200)
+
+      # Verify our named supervisor is running
+      named_supervisor_pid = Oban.Registry.whereis(CustomApp.Jobs.Oban)
+      assert is_pid(named_supervisor_pid), "CustomApp.Jobs.Oban supervisor should be running"
+
+      # Verify we can get its config
+      config = Oban.Registry.config(CustomApp.Jobs.Oban)
+      assert config.name == CustomApp.Jobs.Oban
+
+      # Verify there's no default "Oban" instance
+      default_supervisor_pid = Oban.Registry.whereis(Oban)
+      assert is_nil(default_supervisor_pid), "Default Oban instance should NOT exist"
+
+      named_supervisors = MapSet.new([CustomApp.Jobs.Oban])
+
+      refute_error(fn ->
+        ObanPlugin.execute_queue_metrics(named_supervisors)
+      end)
+    end
+  end
+
+  defp refute_error(fun) do
+    try do
+      fun.()
+      :ok
+    rescue
+      error -> flunk("Expected no error, but got: #{inspect(error)}")
+    end
+  end
 end