Granular Logger

This module is a very simple wrapper around winston in order to provide extra flexibility when using time-based log-rotation.

Compatibility

This module is built on each commit with TravisCI on Node 0.10.x and 0.12.x. In addition, the latest version of io.js on Travis is also used, although compability here is a lower priority. Build results are sent over to Code Climate for analysis.

Be aware that this module has had limited testing outside of use in small projects, and as such caution is advised. The module version is currently below v1.0.0, so the API may change at any time, although I do not anticipate doing so.

Setup

granular-logger is available on npm, so simply install it.

$ npm install granular-logger

Creation

In advance of using this module, you should probably become familiar with both moment and winston.

It's extremely easy to create an instance of a logger, using the constructor defined below. Following is a quick overview of the arguments:

new Log(granularity, filepath[, interval][, winston_opts]);

granularity

The time based granularity to log against, for example day. This can be any granularity recognised by moment except ms (it makes no sense to log based on ms), and is a required argument. You can use long or short forms, e.g. year or y.

filepath

This parameter is the path to the file the logs should output to. This path can contain date strings to be formatted by moment using a {} syntax. Below is an example. This is the main use case behind this module, as it isn't possible to define date-based paths with winston.

var Logger = require('granular-logger');

var logger = new Logger('day', '/tmp/logs/app/{YYYY}/{MM}/{DD}/app.log');

console.log(logger.filepath); // becomes /tmp/logs/app/2015/05/21/app.log

interval

In case you wish to rotate on some other interval than 1 <granular>, this parameter allows you to define the interval before rotation. E.g. granularity: day and interval: 7 would mean a weekly rotation. This parameter is optional, and defaults to 1.

winston_opts

This final parameter is simply passed straight through to the winston instance, in case you wish to customise your logging further. If no options are specified, a default will be used which simply logs any provided String straight to a file appended with \n.

Writing

Calling write will write to the log. The arguments taken match those used by winston as defined here. Please note that the first value of info should not be added; it is inserted automatically.

var Logger = require('granular-logger');

var logger = new Logger('day', '/tmp/logs/app/{YYYY}/{MM}/{DD}/app.log');

logger.write('test_string_%d', 1); // test_string_1

Tests

Tests are controlled by Grunt, so ensure you have the CLI installed.

$ npm test
# or
$ grunt test

You can also generate coverage reports in HTML and lcov formats using:

$ grunt coverage

Issues

If you find any issues inside this module, feel free to open an issue here.