node-file-ensure, a small filesystem utility to make sure a file is there

This weekend we’ve come up with a small utility that will make our life easier, and hopefully yours as well!

We use cascading mechanisms for our configurations, so, for example, we define the config in a few different files:

• base.yml, that has all the common configurations
• dev.yml, which is for local environments
• staging.yml, which is for our staging environment
• live.yml, well…you guessed it!

So, for example, a live.yml might look like:

domain:   'namshi.com'

whereas the base one has many more values:

apis:
  version:   'v1'
  domain:    'api.{{ domain }}'
  baseUrl:   'https://{{ apis.domain }}'

There’s a problem with this approach: if one of the developers wants to change a value in his dev.js git will tell him that the file has changed, which is quite annoying!

To overcome this we always put it in the .gitignore:

dev.yml

and instead commit a dev.yml.example file that has the skeleton of the file, asking everyone, when booting the application for the first time, to copy that file to a dev.js.

Things work flawlessly until you need to do this 10 times (I mean, in 10 projects, like we do) or when you forget this step during the installation and waste a lot of time trying to debug why the application is not running correctly.

To overcome this annoying issue we decided to develop a small utility, node-file-ensure, that does all of this for you:

var ensure = require('file-ensure');

ensure('./config/dev.yml', {from: './config/dev.yml.example'});

Simple as that!

ensure will make sure to create an empty file if it doesnt find the one you specified:

ensure('./config/dev.yml');

and is able to copy the contents from another file, like in the first example above:

ensure('./config/dev.yml', {from: './config/dev.yml.example'});

If you need to run any check after ensure has run, you can provide a callback:

ensure('path/to/config/dev.yml', {src: 'path/to/config/dev.yml.example'}, function(err){
  console.log(fs.readFileSync('path/to/config/dev.yml').toString() === fs.readFileSync('path/to/config/dev.yml.example').toString());
});

That’s it! Tests run through mocha and we’ve set them up on travis, to be on the safe side :)

If you have patches, suggestions or rants…feel free to open an issue on GitHub!