rektide / rotating-writable

Rolling fs.createWriteStream with a hourly timestamp suffix.

Rotating Writable

Rotating Writable is an hourly, auto-rotating writable stream, where the suffix might be 2016-4-29-15. It's built to implement a logger compatible with Amazon Elastic Beanstalk's Enhanced Health Checking.

By default, Rotating Writable opens files as append. It passes options through to fs.createWriteStream, so set the flags as you please to change.

Rotating Writable also defaults to application.log as a filename, if the specified path is found to be a directory. This might be a mis-feature.

Install

npm install rotating-writable

Use

Rotating Writable should fairly transparently substitute in for fs.createWriteStream, but instead of returning the stream, it will return a function which returns the current stream: all operations should call the getter and issue their writes to the current stream instance.

Example

A trivial application might look like-

var rotating = require("rotating-writable")
rotating().write("application starting")
setTimeout(function(){
	rotating().write("application ending")
	rotating.end("application finished")
}, 500)

Caution

Creating a rotating writable issues a fs.statSync. It is not expected that apps need to keep creating rotating writables. If you do have this use case, please submit a PR, perhaps an option to skip this