Add table cleaning job (#3294)

src/invidious/jobs/base_job.cr

@@ -1,3 +1,33 @@
 abstract class Invidious::Jobs::BaseJob
   abstract def begin
+
+  # When this base job class is inherited, make sure to define
+  # a basic "Config" structure, that contains the "enable" property,
+  # and to create the associated instance property.
+  #
+  macro inherited
+    macro finished
+      # This config structure can be expanded as required.
+      struct Config
+        include YAML::Serializable
+
+        property enable = true
+
+        def initialize
+        end
+      end
+
+      property cfg = Config.new
+
+      # Return true if job is enabled by config
+      protected def enabled? : Bool
+        return (@cfg.enable == true)
+      end
+
+      # Return true if job is disabled by config
+      protected def disabled? : Bool
+        return (@cfg.enable == false)
+      end
+    end
+  end
 end

src/invidious/jobs/clear_expired_items_job.cr

@@ -0,0 +1,27 @@
+class Invidious::Jobs::ClearExpiredItemsJob < Invidious::Jobs::BaseJob
+  # Remove items (videos, nonces, etc..) whose cache is outdated every hour.
+  # Removes the need for a cron job.
+  def begin
+    loop do
+      failed = false
+
+      LOGGER.info("jobs: running ClearExpiredItems job")
+
+      begin
+        Invidious::Database::Videos.delete_expired
+        Invidious::Database::Nonces.delete_expired
+      rescue DB::Error
+        failed = true
+      end
+
+      # Retry earlier than scheduled on DB error
+      if failed
+        LOGGER.info("jobs: ClearExpiredItems failed. Retrying in 10 minutes.")
+        sleep 10.minutes
+      else
+        LOGGER.info("jobs: ClearExpiredItems done.")
+        sleep 1.hour
+      end
+    end
+  end
+end