code: function logSetup() {
      JuttleLogger.getLogger = log4js.getLogger;
  
      let levels = {
          '[all]': 'info'
      };
  
      // Handle node.js style debug configuration where DEBUG is a
      // comma-separated list of debug targets, or '*' to enable all
      // debugging.
      let DEBUG = process.env.DEBUG;
      if (DEBUG) {
          let targets = DEBUG.split(',');
          _.each(targets, function(target) {
              if (target === '*') { target = '[all]'; }
              levels[target] = 'debug';
          });
      }
  
      log4js.configure({
          levels: levels,
          appenders: [{type: __dirname + '/stderr-appender'}]
      });
  
      JuttleLogger.getLogger('cli').debug('set logging levels to', levels);
  }
docs: Initialize the Juttle Logger to use log4js. By default all targets are set to info level, but individual targets (or all targets) can be enabled at debug level with the DEBUG environment letiable.