More robust PuSH subscription refreshes (#2799)

* Fix #2473 - Use sidekiq scheduler to refresh PuSH subscriptions instead of cron

Fix an issue where / in domain would raise exception in TagManager#normalize_domain

PuSH subscriptions refresh done in a round-robin way to avoid hammering a single
server's hub in sequence. Correct handling of failures/retries through Sidekiq (see
also #2613). Optimize Account#with_followers scope. Also, since subscriptions
are now delegated to Sidekiq jobs, an uncaught exception will not stop the entire
refreshing operation halfway through

Fix #2702 - Correct user agent header on outgoing http requests

* Add test for SubscribeService

* Extract #expiring_accounts into method

* Make mastodon:push:refresh no-op

* Queues are now defined in sidekiq.yml

* Queues are now in sidekiq.yml

1 files changed, 7 insertions, 3 deletions

diff --git a/app/helpers/http_helper.rb b/app/helpers/http_helper.rb
index 1697de746..e39a52da0 100644
--- a/app/helpers/http_helper.rb
+++ b/app/helpers/http_helper.rb
@@ -1,13 +1,17 @@
 # frozen_string_literal: true
 
 module HttpHelper
-  USER_AGENT = "#{HTTP::Request::USER_AGENT} (Mastodon/#{Mastodon::Version}; +http://#{Rails.configuration.x.local_domain}/)"
-
   def http_client(options = {})
     timeout = { write: 10, connect: 10, read: 10 }.merge(options)
 
-    HTTP.headers(user_agent: USER_AGENT)
+    HTTP.headers(user_agent: user_agent)
         .timeout(:per_operation, timeout)
         .follow
   end
+
+  private
+
+  def user_agent
+    @user_agent ||= "#{HTTP::Request::USER_AGENT} (Mastodon/#{Mastodon::Version}; +http://#{Rails.configuration.x.local_domain}/)"
+  end
 end