Add a circuit breaker for ActivityPub deliveries (#7053)

app/workers/activitypub/delivery_worker.rb

@@ -12,9 +12,7 @@ class ActivityPub::DeliveryWorker
     @source_account = Account.find(source_account_id)
     @inbox_url      = inbox_url
 
-    perform_request do |response|
-      raise Mastodon::UnexpectedResponseError, response unless response_successful? response
-    end
+    perform_request
 
     failure_tracker.track_success!
   rescue => e
@@ -30,8 +28,14 @@ class ActivityPub::DeliveryWorker
     request.add_headers(HEADERS)
   end
 
-  def perform_request(&block)
-    build_request.perform(&block)
+  def perform_request
+    light = Stoplight(@inbox_url) do
+      build_request.perform do |response|
+        raise Mastodon::UnexpectedResponseError, response unless response_successful?(response)
+      end
+    end
+
+    light.run
   end
 
   def response_successful?(response)