A port of log4js to node.js
You’ll need to use the logLevelFilter. Here’s an example configuration:
log4js.configure({
appenders: {
everything: { type: 'file', filename: 'all-the-logs.log' },
emergencies: { type: 'file', filename: 'oh-no-not-again.log' },
'just-errors': { type: 'logLevelFilter', appender: 'emergencies', level: 'error' }
},
categories: {
default: { appenders: ['just-errors', 'everything'], level: 'debug' }
}
});
const logger = log4js.getLogger();
logger.debug('This goes to all-the-logs.log');
logger.info('As does this.');
logger.error('This goes to all-the-logs.log and oh-no-not-again.log');
Previous versions of log4js used to watch for changes in the configuration file and reload when it changed. It didn’t always work well, sometimes leaving file handles or sockets open. This feature was removed in version 2.x. As a replacement, I’d suggest using a library like watchr to notify you of file changes. Then you can call log4js.shutdown
followed by log4js.configure
again.
replaceConsole
- it doesn’t work any more?I removed replaceConsole
- it caused a few weird errors, and I wasn’t entirely comfortable with messing around with a core part of node. If you still want to do this, then code like this should do the trick:
log4js.configure(...); // set up your categories and appenders
const logger = log4js.getLogger('console');
console.log = logger.info.bind(logger); // do the same for others - console.debug, etc.