node-logger

Centralized logger for 17.Media Node.JS projects

... in the fires of Mount Doom, the dark lord Sauron forged, in secret, a master logger to control all others. "One logger to log them all!"

Usage

First of all you have to set up your configs:

import { Level } from '@17media/node-logger';

const loggerConfig = {
  // configs shared by all log services
  base: {
    // minimum level to trigger logger [ERROR|WARN|INFO|DEBUG]
    // levels lower than this will not be logged
    // it can be overridden in each service specific config
    logLevel: Level.INFO,

    // project name, preferably 'name' from package.json
    project: require('~/package.json').name,

    // environment [production|stage|development]
    environment: 'production',
  },

  // configs for slack
  Slack: {
    // override minimum log level (optional)
    logLevel: Level.WARN,

    // slack bot access token
    slackToken: SLACK_BOT_TOKEN,

    // slack channel to log messages to
    slackChannel: SLACK_BOT_ALERT_CHANNEL,
  },

  // configs for log collecting service (fluentD)
  Fluentd: {
    // override minimum log level (optional)
    logLevel: Level.INFO,

    // log collector URL
    collectorUrl: LOG_COLLECTOR_URL,
  },

  // configs for logging to console
  Console: {
    // override minimum log level (optional)
    logLevel: Level.ERROR,
  },
};

Then, there are two ways to continue, the easy way and the complete way:

Easy Way

This is the simple way and should cover ~90% of the use cases.

const logger = require('@17media/node-logger').createLogger(loggerConfig)('some:label');

logger.debug('track the variable value during development', { info });
logger.info('somehing worth logging for future reference', { additionalInfo });
logger.warn('somehing worth notice', { additionalInfo });
logger.error('somehing terrible happened', new Error());
logger.fatal('somehing disastrous happened', new Error(), { additionalInfo });

Complete Way

Provide configs to initiate the logger: A log service will be used only when all corresponding configs are provided.

const { Logger } = require('@17media/node-logger');
const logger = new Logger(loggerConfig);

Use the logger like:

const { LogMessage } = require('@17media/node-logger');

logger.Log(
  Level.WARN,
  new LogMessage('something happened', { additionalInfo }),
  'some:label:for:the:message'
);

In most situations you would want to pre-label all the messages logged in a file. You can do it by:

const labelledLogger = logger.Label('path:to:this:file');

labelledLogger.Log(
  Level.WARN,
  new LogMessage('something happened', { additionalInfo })
);

You can extend LogMessage and ErrorMessage to create customized formatting for your context.