Merge branch 'gun-pool-retry' into 'develop'

Gun connection pool retry fix

See merge request pleroma/pleroma!4076

changelog.d/gun_pool2.fix

@@ -0,0 +1 @@
+Connection pool errors when publishing an activity is a soft-error that will be retried shortly.

lib/pleroma/gun/connection_pool/worker_supervisor.ex

@@ -21,7 +21,7 @@ defmodule Pleroma.Gun.ConnectionPool.WorkerSupervisor do
   def start_worker(opts, retry \\ false) do
     case DynamicSupervisor.start_child(__MODULE__, {Pleroma.Gun.ConnectionPool.Worker, opts}) do
       {:error, :max_children} ->
-        funs = [fn -> !retry end, fn -> match?(:error, free_pool()) end]
+        funs = [fn -> retry end, fn -> match?(:error, free_pool()) end]
 
         if Enum.any?(funs, fn fun -> fun.() end) do
           :telemetry.execute([:pleroma, :connection_pool, :provision_failure], %{opts: opts})

lib/pleroma/web/activity_pub/publisher.ex

@@ -129,6 +129,10 @@ defmodule Pleroma.Web.ActivityPub.Publisher do
           _ -> {:error, e}
         end
 
+      {:error, :pool_full} ->
+        Logger.debug("Publisher snoozing worker job due to full connection pool")
+        {:snooze, 30}
+
       e ->
         unless params[:unreachable_since], do: Instances.set_unreachable(inbox)
         Logger.metadata(activity: id, inbox: inbox)