yamlconf

An alternative approach to the application configuration, with yaml and env variables.

Getting started

To start using this, simply require yamlconf function and call it:

const config = require('yamlconf')();

It will load configuration defined in ./config.yml file.

Also, it will look for ./config.local.yml file and if it's found, it will merge values with normal config, local values taking precedence.

Configuration

Pass the path to the config file as a string:

const config = require('yamlconf')('./path/to/config.yml');

Pass the configuration object for more options:

Property	Meaning	Defaults to
path	filepath to config	./config.yml
loadToProcess	when it's true, config will be available globally in process.config	false
dotenv	configuration for .env file
dotenv.path	filepath to .env file	./env
dotenv.silent	should not warn if .env file is missing	true
localConfig	configuration object for local config
localConfig.path	path to local config	'./config.local.yml'
localConfig.force	specify if localConfig should be always loaded, fails if doesn't exists	false

Reasons to implement this

Why yet another npm module for app configuration?

Yes, you are right, there are plenty of them, you may know node-yaml-config or yaml-config, but none of them actually conform with something I would call "good manners". What are they?

• You should NOT define special blocks of configuration for each of your environments. If you do this, you may quickly end up with huge file containing something like this:

  dev-123-feature:
    apiLimit: 123
    
  stage-2.1:
    debug: false
  ...
  

  Instead, you should have just one config file and the values defined there can be overridden by "local" configuration if needed.

  In practice, you have config.yml and your CI tool (or developer) may add config.local.yml during build process to successfully setup the application with desired configuration. Important note here: This custom local configuration file should't be tracked by VCS.

• You should be able to set credentials and secret keys easily without exposing them in source code.

  Environment variables suit the best for this - you can define them on the fly and out of the scope of the application source code.

  Yamlconf supports both environment variables and .env file, so you can define configuration in this way:

  In .env:

  REDIS=redis://yourhost:6379
  

  and in config.yml:

  services:
    redis: process.env.REDIS
  

  It should be already obvious, but I strictly discourage you to have .env tracked by VCS.

• The philosophy behind yamlconf should match with "The twelve-factor app" methodology.

Why YAML and not JSON?

IMHO because json is not simply the appropriate format for the configuration. For example:

• It's too verbose and no human friendly.
• You have to edit also an already existing line when adding new object property or array item.
• You can't use comments at all.