Logback: Enable shutdownHook using Groovy configuration

Question

I'm using logback 1.1.10 with groovy configuration. I recently discovered shutdownHook preference but I haven't found the way to enable it using groovy configuration. Is this possible? Or a missing feature?

Answer 1

Logback's shutdownHook was added in v1.1.3 and it can be configured using Groovy. The docs are a bit light on this matter and the xml->groovy translator ignores the shutdownHook but I have verified the inclusion of a shutdown hook via Groovy config as follows:

  import ch.qos.logback.classic.AsyncAppender
  import ch.qos.logback.classic.PatternLayout
  import ch.qos.logback.classic.encoder.PatternLayoutEncoder
  import ch.qos.logback.core.ConsoleAppender
  import static ch.qos.logback.classic.Level.INFO

  scan("30 seconds")

  statusListener(OnConsoleStatusListener)

  def shutdownHook() {
      def shutdownHook = new ch.qos.logback.core.hook.DelayingShutdownHook();
      shutdownHook.setContext(context);

      def Thread hookThread = new Thread(shutdownHook, "Logback shutdown hook [" + context.name + "]");
      context.putObject("SHUTDOWN_HOOK", hookThread);
      Runtime.getRuntime().addShutdownHook(hookThread);
  }

  shutdownHook();

  appender("Console-Appender", ConsoleAppender) {
      encoder(PatternLayoutEncoder) {
          pattern = "%d|%-5p|%t|%msg%n"
      }
  }

  logger("com", INFO, ["Console-Appender"], false)

  root(INFO, ["Console-Appender"])

This was confirmed by running a Java process which used logback, explicitly pointing to the above configuration by using -Dlogback.configurationFile and the resulting output clearly shows the shutdown hook being used:

08:47:47,705 |-INFO in ch.qos.logback.classic.gaffer.ConfigurationDelegate@7ce97ee5 - Setting ReconfigureOnChangeTask scanning period to 30 seconds
08:47:47,728 |-INFO in ch.qos.logback.classic.gaffer.ConfigurationDelegate@7ce97ee5 - Added status listener of type [ch.qos.logback.core.status.OnConsoleStatusListener]
08:47:47,750 |-INFO in ch.qos.logback.classic.gaffer.ConfigurationDelegate@7ce97ee5 - About to instantiate appender of type [ch.qos.logback.core.ConsoleAppender]
08:47:47,752 |-INFO in ch.qos.logback.classic.gaffer.ConfigurationDelegate@7ce97ee5 - Naming appender as [Console-Appender]
08:47:47,902 |-INFO in ch.qos.logback.classic.gaffer.ConfigurationDelegate@7ce97ee5 - Setting level of logger [com] to INFO
08:47:47,911 |-INFO in ch.qos.logback.classic.gaffer.ConfigurationDelegate@7ce97ee5 - Attaching appender named [Console-Appender] to Logger[com]
08:47:47,915 |-INFO in ch.qos.logback.classic.gaffer.ConfigurationDelegate@7ce97ee5 - Setting level of logger [ROOT] to INFO
08:47:47,915 |-INFO in ch.qos.logback.classic.gaffer.ConfigurationDelegate@7ce97ee5 - Attaching appender named [Console-Appender] to Logger[ROOT]
2017-08-01 08:47:48,072|INFO |main|yippee!
Disconnected from the target VM, address: '127.0.0.1:57421', transport: 'socket'
08:47:48,131 |-INFO in ch.qos.logback.core.hook.DelayingShutdownHook@6765f751 - Sleeping for 0 milliseconds
08:47:48,131 |-INFO in ch.qos.logback.core.hook.DelayingShutdownHook@6765f751 - Logback context being closed via shutdown hook