Fixes #36856 - add check for katello-rake task

definitions/checks/katello/check_clean_backend_objects.rb

@@ -0,0 +1,45 @@
+module Checks::Katello
+  class CheckCleanBackendObjects < ForemanMaintain::Check
+    metadata do
+      description 'Check whether subscription consumers of backend service is in sync'
+      tags :pre_upgrade
+
+      confine do
+        feature(:katello)
+      end
+    end
+
+    def warn_hosts(missing_sub_info)
+      unless missing_sub_info.empty?
+        puts "Hosts missing subscription information and would be un-registered:"
+        puts missing_sub_info.map { |e| "  * #{e[1]}(#{e[0]})" }.join("\n")
+      end
+    end
+
+    def clean_backend_objects_dry_run
+      found_orphans = nil
+      missing_sub_info = []
+      list_cmd = "export RUBYOPT='-W0'; foreman-rake katello:clean_backend_objects"
+      execute(list_cmd).each_line do |line|
+        case line
+        when /^(?<orphans>\d+) orphaned consumer id\(s\) found in candlepin\.$/
+          found_orphans = Regexp.last_match(:orphans).to_i
+          puts "Found #{found_orphans} orphans" if found_orphans > 0
+        when /^Candlepin orphaned consumers: (?<orphaned_consumers>.*)$/
+          orphaned_consumers = Regexp.last_match(:orphaned_consumers)
+          puts "Found consumers: #{orphaned_consumers}" if orphaned_consumers != '[]'
+        when /^Host (?<id>\S*) (?<host>\S*) (?<sub>\S*)? is partially missing subscription/
+          missing_sub_info << [Regexp.last_match(:id), Regexp.last_match(:host)]
+        end
+      end
+      warn_hosts(missing_sub_info)
+      return found_orphans + missing_sub_info.length
+    end
+
+    def run
+      assert clean_backend_objects_dry_run.zero?,
+        "'katello:clean_backend_objects' would remove the above Candlepin consumers and hosts!\n" \
+        "Please verify, if this is valid. One solution can be to re-subscribe affected host.\n"
+    end
+  end
+end