DHLog

A simple logger to be used in node.js, that can be configured with different outputs.

Usage

Get a logger in your module:

const log = require('dhlog').forModule(module);
log.debug('This is a debug output');
log.info('This is an info output');
log.warn('This is a warning output');
log.error('This is an error output');

By default only logging to the console is activated.

Configuration

You can supply a custom logging configuration either per file or per environment variable. The environment variable takes precedence.

• Create a file named dhlog.json in your working directory
• Create the environment variable DHLOG with the config as json string

Example configuration:

{
  "outputs": [
    {"type": "consoleOutput", "maxLevel": 4},
    {"type": "fileOutput","path": "./logs/default.log","maxLevel": 4}
  ]
}

Log outputs

All output modules support all the option:

• maxLevel the maximum log level that should be logged.
  • 4: debug
  • 3: info
  • 2: warn
  • 1: error

consoleOutput

This output module maps the log functions to the functions of the console.

fileOutput

This output module writes all log statements to a file and rotates the file when it gets too large.

Options:

• path the file path where the log should be written to
• maxFileSize maximum bytes that should be written to a file before it is rotated
• maxFileCount maximum count of rotated files to keep

When a file is full, the output module will rename the logfile and open a new one. The rotated files get a timestamp as suffix.

License

The MIT License (MIT)