maintenance: break maintenance tasks into individual jobs.

Break the hourly/daily/weekly/monthly maintenance tasks down into
individual delayed jobs. This way if one task fails, it won't prevent
other tasks from running. Also, jobs can be run in parallel, and can be
individually retried if they fail.

app/logical/danbooru_maintenance.rb

@@ -2,45 +2,34 @@ module DanbooruMaintenance
   module_function
 
   def hourly
-    safely { Upload.prune! }
-    safely { PostPruner.prune! }
-    safely { RateLimit.prune! }
-    safely { regenerate_post_counts! }
+    queue PruneUploadsJob
+    queue PrunePostsJob
+    queue PruneRateLimitsJob
+    queue RegeneratePostCountsJob
   end
 
   def daily
-    safely { Delayed::Job.where('created_at < ?', 45.days.ago).delete_all }
-    safely { PostDisapproval.prune! }
-    safely { BulkUpdateRequestPruner.warn_old }
-    safely { BulkUpdateRequestPruner.reject_expired }
-    safely { Ban.prune! }
-    safely { BigqueryExportService.async_export_all! }
-    safely { ActiveRecord::Base.connection.execute("vacuum analyze") unless Rails.env.test? }
+    queue PruneDelayedJobsJob
+    queue PrunePostDisapprovalsJob
+    queue PruneBulkUpdateRequestsJob
+    queue PruneBansJob
+    queue BigqueryExportAllJob
+    queue VacuumDatabaseJob
   end
 
   def weekly
-    safely { TagRelationshipRetirementService.find_and_retire! }
-    safely { ApproverPruner.dmail_inactive_approvers! }
+    queue RetireTagRelationshipsJob
+    queue DmailInactiveApproversJob
   end
 
   def monthly
-    safely { ApproverPruner.prune! }
+    queue PruneApproversJob
   end
 
-  def regenerate_post_counts!
-    updated_tags = Tag.regenerate_post_counts!
-    updated_tags.each do |tag|
-      DanbooruLogger.info("Updated tag count", tag.attributes)
-    end
-  end
-
-  def safely(&block)
-    ActiveRecord::Base.connection.execute("set statement_timeout = 0")
-
-    CurrentUser.scoped(User.system, "127.0.0.1") do
-      yield
-    end
-  rescue StandardError => exception
+  def queue(job)
+    DanbooruLogger.info("Queueing #{job.name}")
+    job.perform_later
+  rescue Exception # rubocop:disable Lint/RescueException
     DanbooruLogger.log(exception)
     raise exception if Rails.env.test?
   end