node-config-yml

Yaml Config for Node.js

Install

$ yarn add node-config-yaml

or

$ npm install node-config-yaml

Usage

Use config for yaml config files in Node.js projects. For example you might have a project with the following config.yml file in the project dir.

1
2app:
3    url: http://myapp.com/home
4    cache: redis
5
6db:
7    location: mysql-db-prod
8

This config can be accessed like this.

1
2var config = require('node-config-yaml').load();
3
4console.log(config.app.url);
5console.log(config.app.cache);
6console.log(config.db.location);
7

You can might use:

1
2var config = require('node-config-yaml')
3
4.load() // load config from config.yml in root project directory
5.load('file') // load config from .yml file
6.load('dir') // load all .yml files in directory to config
7.load(['dir', 'file']) // load .yml files from sources to config
8.load(['some_sources'], { root: 'root_file_name' }) // load .yml files from sources to config with root_file_name as root (default: config)
9

Substitution

You can substitute variables in the config.yml like this.

1
2dns: myapp.com
3
4app:
5    url: http://${dns}/home
6    cache: redis
7
8db:
9    location: mysql-db-prod
10

This config would yield the following.

1
2console.log(config.app.url);
3
4// outputs - http://myapp.com/home
5

Config Folder

Instead of having a file named config.yml with all of your environment settings in place, you could have a config folder at the root level of your project. This module will read in every .yml file, and return an object that looks like:

1{
2    [file-name]: [parsed-file-contents],
3    ...,
4} 

if you need to do cross-file referencing, you can, via dot-notation:

1# file `a.yml`
2foo: bar

1#file `b.yml`
2baz: ${a.foo}

will get you

1{
2    a: {foo: 'bar'},
3    b: {baz: 'bar'}
4}

with root options:

1# file `a.yml`
2foo: bar

1#file `b.yml`
2baz: ${foo}

will get you

1.load(['a.yml', 'b.yml'], { root: 'a' }
2
3{
4    foo: 'bar',
5    b: {baz: 'bar'}
6}

Environment Specific Settings

Based on an Environment ID, you can designate specific override settings for different types of environments. First you have to specify your Environment ID. You can do so in one of several ways. The first Environment ID that is found in the following order wins.

1. --env command line argument
2. --${static-environment} command line argument
3. ENVIRONMENT_ID process environment setting
4. git branch name with regex filtering

Static Environments

To understand this better let's first talk about Static Environments. These are environments that have their own environment specific settings or Environment Overrides. Not necessarily all environments have their own environment specific settings, but those that do should be defined as Static Environments in the config.yml as follows:

1
2environments:
3    static:
4        - dev
5        - test
6        - prod
7

Keys as environments

The other approach you can take is to have top level keys that only consist of your environments.

Using a single config.yml file

setup your config.yml as follows:

1dev:
2    # ...
3test:
4    # ...
5prod:
6    # ...

Using a Config folder.

Your filenames determine the keys, so your directory could be set as follows:

config/dev.yml
config/test.yml
config/prod.yml

Environment ID: --env Argument

Set the Environment ID using --env command line argument.

node app.js --env feature-xyz

This is often helpful when running gulp tasks.

gulp deploy --env feature-xyz

Environment ID: --${static-environment} Argument

For Static Environments set the Environment ID using the static environment id as an argument.

gulp deploy --prod

Environment ID: ENVIRONMENT_ID

Set the Environment ID using ENVIRONMENT_ID process environment variable.

export ENVIRONMENT_ID=feature-xyz

Environment ID: git branch

If an Environment ID is not found using one of the other methods, it will use the git branch for the current project folder. This branch can be filtered using regex. Let's say your current branch is Features/ISSUE-123-feature-xyz, and you have the following setting in your config.yml.

1
2branchRegex: Features/ISSUE-\d+-((\w|-)+)
3

The Environment ID will be feature-zyz. If no branchRegex is given the branch name will be taken as is.

Environment ID Substitution

The Environment ID can be substituted into the config.yml. Let's say you have an Environment ID feature-xyz and the following config.yml.

1dns: ${envId}.myapp.com
2
3app:
4    url: http://${dns}/home
5    cache: redis
6
7db:
8    location: MYSQL-DB-${ENVID}

This will yield the following:

1var config = require('node-config-yaml').load();
2
3console.log(config.dns);          // feature-xyz.myapp.com
4console.log(config.app.url);      // http://feature-xyz.myapp.com
5console.log(config.db.location);  // MYSQL-DB-FEATURE-XYZ
6

Environment Overrides

For Static Environments, settings can be overridden for that specific environment. For example, with the following config.yml:

1dns: ${envId}.myapp.com
2
3app:
4    url: http://${dns}/home
5    cache: redis
6
7db:
8    location: MYSQL-DB-${ENVID}
9
10prod:
11    app:
12        url: https://${dns}
13    db:
14        location: DB-${ENVID}
15

and the following app.js file:

1var config = require('node-config-yaml').load();
2
3console.log(config.dns);
4console.log(config.app.url);
5console.log(config.app.cache);
6console.log(config.db.location);
7

the following command:

node app.js --prod

would output the following:

prod.myapp.com
https://prod.myapp.com
redis
MYSQL-DB-PROD

Credits:

config-yml

https://github.com/Nordstrom/config