Programmatically configuring Log4j2 with ConfigurationBuilder

Question

Im using Log4j2 2.6.2.At the start of the application, I'm calling the following code

ConfigurationBuilder< BuiltConfiguration > builder = ConfigurationBuilderFactory.newConfigurationBuilder();
builder.setStatusLevel( Level.ERROR );
builder.setConfigurationName("OverrideDefaultConsoleLayout");
AppenderComponentBuilder appenderBuilder = builder.newAppender("Stdout", "CONSOLE").addAttribute("target", ConsoleAppender.Target.SYSTEM_OUT);
appenderBuilder.add(builder.newLayout("PatternLayout").addAttribute("pattern", "%% %msg%n"));       
builder.add(appenderBuilder);
builder.add(builder.newLogger("Log4j2Test", Level.DEBUG).add(builder.newAppenderRef("Stdout")).addAttribute("additivity", false));
builder.add(builder.newRootLogger(Level.DEBUG).add(builder.newAppenderRef("Stdout")));
Configurator.initialize(builder.build());
LogManager.getLogger("Log4j2Test").error("Output % followed by this message");

I referred to the following documentation: http://logging.apache.org/log4j/2.x/manual/customconfig.html

My goal is to programmatically configure Log4j2. As a trial, I'm trying to override the default layout for the console Appender.

No configuration file (.properties, .xml) is available to the application. As a result, on startup, the following message is displayed.

ERROR StatusLogger No log4j2 configuration file found. Using default configuration: logging only errors to the console.

The output is displayed as

15:43:50.865 [main] ERROR Log4j2Test - Output % followed by this message

i.e. the default layout is in use. My programmatic override of the default is not working. Can anyone help in rectifying the code?

Remko Popma Remko Popma · Accepted Answer · 2016-10-04T07:40:07

Just calling the code you showed may not work. It needs to be coded as a class extending ConfigurationFactory, and annotated with @Plugin so that Log4j can discover it and use it instead of looking for a configuration file.

The example code on the Log4j manual page you link to shows how to do this.

Programmatically configuring Log4j2 with ConfigurationBuilder

1 Answers