log4js-node

A port of log4js to node.js

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Multiprocess Appender

You probably want to use the tcp server or tcp appender instead of this - they are more flexible

Note that if you’re just using node core’s cluster module then you don’t need to use this appender - log4js will handle logging within the cluster transparently.

The multiprocess appender sends log events to a master server over TCP sockets. It can be used as a simple way to centralise logging when you have multiple servers or processes. It uses the node.js core networking modules, and so does not require any extra dependencies. Remember to call log4js.shutdown when your application terminates, so that the sockets get closed cleanly.

Configuration

Example (master)

log4js.configure({
  appenders: {
    file: { type: 'file', filename: 'all-the-logs.log' },
    server: { type: 'multiprocess', mode: 'master', appender: 'file', loggerHost: '0.0.0.0' }
  },
  categories: {
    default: { appenders: ['file'], level: 'info' }
  }
});

This creates a log server listening on port 5000, on all IP addresses the host has assigned to it. Note that the appender is not included in the appenders listed for the categories. Also note that the multiprocess master appender will send every event it receives to the underlying appender, regardless of level settings.

Example (worker)

log4js.configure({
  appenders: {
    network: { type: 'multiprocess', mode: 'worker', loggerHost: 'log.server' }
  },
  categories: {
    default: { appenders: ['network'], level: 'error' }
  }
});

This will send all error messages to log.server:5000.