Node-config tutorial
last modified October 18, 2023
In this article we show how to create configuration files for Node applications with node-config module.
Node-config
Node-config creates configuration files for application deployments.
Node-config allows us to define a set of default parameters and extend them for different deployment environments (development, qa, staging, production, etc.).
The configuration files are located in the default config
directory. The location can be overriden with the NODE_CONFIG_DIR
environment variable. The NODE_ENV environment variable contains
the name of our application's deployment environment; it is
development by default.
Node config supports various configuration file formats, including JSON, YAML,
properties, or XML. The default configuration file is default.json
(or default.yaml, default.xml). If we use a production
deployment, then the configuration is loaded from production.json.
Setting up Node-config
First, we install node-config.
$ npm init -y
We initiate a new Node application.
$ npm i config
We install node-config with nmp i config.
$ npm i js-yaml
In addition, we install js-yaml for YAML support.
Node-config example
The following example retrieves configuration data with config
package.
{
"app": {
"port": 3000
},
"db": {
"host": "localhost",
"port": 27017,
"name": "ydb"
}
}
We have default.json in the config directory.
const config = require('config');
let appPort = config.get('app.port');
console.log(`Application port: ${appPort}`);
let dbHost = config.get('db.host');
console.log(`Database host: ${dbHost}`);
let dbPort = config.get('db.port');
console.log(`Database port: ${dbPort}`);
let dbName = config.get('db.name');
console.log(`Database name: ${dbName}`);
console.log('NODE_ENV: ' + config.util.getEnv('NODE_ENV'));
We load the config package and get the values
with config.get function. The default deployment
type is specified in NODE_ENV.
$ node simple.js Application port: 3000 Database host: localhost Database port: 27017 Database name: ydb NODE_ENV: development
Node-config example II
We change the configuration file to YAML and set a production deployment environment.
app: port: 3000 db: host: localhost port: 27017 name: ydb
This is default.yaml file.
app: port: 3300 db: host: localhost port: 27017 name: mydb
This is production.yaml file.
const config = require('config');
let appPort = config.get('app.port');
console.log(`Application port: ${appPort}`);
...
The simple.js file is the same.
$ node simple.js Application port: 3000 Database host: localhost Database port: 27017 Database name: ydb NODE_ENV: development
This is the output for the default environment. The configuration is loaded from
default.yaml.
$ set NODE_ENV=production $ node simple.js Application port: 3300 Database host: localhost Database port: 27017 Database name: mydb NODE_ENV: production
We change the NODE_ENV variable with the set command.
(Use export on Linux.) Now the configuration data is loaded from
production.yaml file.
Source
In this article we have used node-config package to create
configuration files for our Node.js application.