log4bro

log4bro makes it hassle free to have compliant microservice ELK stack log behaviour
just require & init and log via global variable in a few seconds
you can run in production mode to automatically switch log-levels
you can run in dockerMode to stop logfile writing and change output to json fields
you can attach some extra fields to json logs so that they are also loved by your ELK stack and your sysops
node + docker + log4bro = happy you, happy ELK stack and happy sysops
comes batteries included for express.js users (check /examples/express_example.js)
auto. access log in ELK format (cout or file)
switch log-level dynamically example: global.LOG.changeLogLevel("INFO");

simple example

const Logger = require("log4bro");

const options = {
  productionMode: true, //switches loglevel between DEBUG and WARN
  logDir: "logs", //relative directory to write log file to
  silence: false, //silences logger
  loggerName: "dev", //ignore
  dockerMode: true, //disables output to logfile
  varKey: "LOG" //name of global variable
};

const logger = new Logger(options);

LOG.trace("bla");
LOG.debug("bla");
LOG.info("bla");
LOG.warn("bla");
LOG.error("bla");
LOG.fatal("bla");