How do I change log level in runtime without restarting Vert.x application

Question

I know that we can change log level by putting it in vertx-default-jul-logging.properties file.

java.util.logging.ConsoleHandler.formatter=java.util.logging.SimpleFormatter
java.util.logging.ConsoleHandler.level=FINER

java.util.logging.FileHandler.limit=10000000
java.util.logging.FileHandler.count=10
java.util.logging.FileHandler.level=FINER
java.util.logging.FileHandler.formatter=java.util.logging.SimpleFormatter

But I need to restart the application when we change log level in this file as it gets built with application. Is there any way to change the log level without restarting the application like we can do in jboss by jboss cli.

Answer 1

This file doesn't have to be built with the application. It just has to be on the classpath.

But anyway, I don't believe JDK logging supports hot reload of a configuration file. There are other logging tools which do though. Like Logback-classic .

Logback-classic can scan for changes in its configuration file and automatically reconfigure itself when the configuration file changes.

For example, to reload every five seconds:

<configuration scan="true" scanPeriod="5 seconds" > 
  ...
</configuration> 

Vert.x can be configured to use different logging frameworks . To do so, you must set the vertx.logger-delegate-factory-class-name system property. As Logback-classic is an slf4j implementation, you need:

-Dvertx.logger-delegate-factory-class-name=io.vertx.core.logging.SLF4JLogDelegateFactory