Prevent sonar timeouts bubbling into the stager

A clogged Ecto pool could cause cascading errors on startup due to a
sequence of calls between the `Notifier`, `Sonar`, and `Stager`.

1. `Sonar` sends a notification in `handle_continue` on startup.
2. The notification is blocked while the `Notifier` waits for a
   connection from the Ecto pool.
3. `Stager` checks for the connection status on startup, which would
   eventually time out because the `Sonar` hadn't finished initializing.
4. The `Stager` crashes from the timeout error.

This makes the folloing changes to prevent this sequence of events:

1. The `Stager` no longer gets the sonar status during startup.
2. The `Notifier` catches timeout errors from `Sonar` checks, warns
   about it, then returns an `:unknown` status.

lib/oban/job.ex

@@ -79,11 +79,11 @@ defmodule Oban.Job do
           {:args, args()}
           | {:max_attempts, pos_integer()}
           | {:meta, map()}
-          | {:priority, pos_integer()}
+          | {:priority, 0..9}
           | {:queue, atom() | binary()}
-          | {:schedule_in, schedule_in_option()}
-          | {:replace_args, boolean()}
           | {:replace, [replace_option() | replace_by_state_option()]}
+          | {:replace_args, boolean()}
+          | {:schedule_in, schedule_in_option()}
           | {:scheduled_at, DateTime.t()}
           | {:tags, tags()}
           | {:unique, [unique_option()]}
@@ -101,7 +101,7 @@ defmodule Oban.Job do
           attempted_by: [binary()] | nil,
           max_attempts: pos_integer(),
           meta: map(),
-          priority: non_neg_integer(),
+          priority: 0..9,
           inserted_at: DateTime.t(),
           scheduled_at: DateTime.t(),
           attempted_at: DateTime.t() | nil,

lib/oban/notifier.ex

@@ -77,6 +77,8 @@ defmodule Oban.Notifier do
 
   alias Oban.{Config, Registry, Sonar}
 
+  require Logger
+
   @type channel :: atom()
   @type name_or_conf :: Oban.name() | Config.t()
   @type payload :: map() | [map()]
@@ -246,6 +248,11 @@ defmodule Oban.Notifier do
     name
     |> Oban.Registry.via(Sonar)
     |> GenServer.call(:get_status)
+  catch
+    :exit, {:timeout, _} = reason ->
+      Logger.warning("Oban.Notifier.status/1 check failed due to #{inspect(reason)}.")
+
+      :unknown
   end
 
   @doc false

lib/oban/stager.ex

@@ -40,17 +40,7 @@ defmodule Oban.Stager do
     # Init event is essential for auto-allow and backward compatibility.
     :telemetry.execute([:oban, :plugin, :init], %{}, %{conf: state.conf, plugin: __MODULE__})
 
-    {:ok, state, {:continue, :start}}
-  end
-
-  @impl GenServer
-  def handle_continue(:start, %State{} = state) do
-    state =
-      state
-      |> schedule_staging()
-      |> check_mode()
-
-    {:noreply, state}
+    {:ok, schedule_staging(state)}
   end
 
   @impl GenServer
@@ -62,6 +52,7 @@ defmodule Oban.Stager do
 
   @impl GenServer
   def handle_info(:stage, %State{} = state) do
+    state = check_mode(state)
     meta = %{conf: state.conf, leader: Peer.leader?(state.conf), plugin: __MODULE__}
 
     :telemetry.span([:oban, :plugin], meta, fn ->
@@ -74,12 +65,7 @@ defmodule Oban.Stager do
       end
     end)
 
-    state =
-      state
-      |> schedule_staging()
-      |> check_mode()
-
-    {:noreply, state}
+    {:noreply, schedule_staging(state)}
   end
 
   defp stage_and_notify(true = _leader, state) do