@terran-source/dotconfig

dotconfig

[Deprecated] App configuration made simple for Node.js. Now moved to

Supports:

1. app configuration file of type json or env (custom type parser can also be implemented through implementing IParser & using setparser)
2. Environment specific configuration overloading
3. Now with the power of interpolate-json to support interpolation (or parameter substitution) inside app-configuration (strongly recommend to go through the documentation to know the full power of interpolation)

Install

# with npm
npm install @terran-source/dotconfig

# or with Yarn
yarn add @terran-source/dotconfig

Usage

Declaration

// declare the variable at the beginning
const { loadConfig } = require('@terran-source/dotconfig');

json

/**
*    App Directory structure
*
*    app/
*     | -- package.json
*     | -- index.js
*     | -- app-config.json
*     | -- app-config.dev.json
*     | -- app-config.test.json
*     | -- app-config.prod.json
*
*/

// ** app-config.json **
{
  "scheme": "http",
  "server": "localhost",
  "port": "8080",
  "baseKey": "baseValue",
  "user": {
    "name": "${USER_NAME}",
    "password": "${USER_PASSWORD}"
  },
  "url": "${scheme}://${=${user.name}.toLowerCase()=}:${= encodeURIComponent(${user.password}) =}@${server}:${port}"
}

// ** app-config.dev.json **
{
  "baseKey": "devValue",
   "someDevKey": "someDevValue"
}

// ** app-config.test.json **
{
  "scheme": "https",
  "server": "test.example.com",
  "baseKey": "testValue"
}

// ** app-config.prod.json **
{
  "scheme": "https",
  "server": "${APP_SERVER_NAME}",
  "port": "${APP_PORT}",
  "baseKey": "${BASE_KEY}"
}

// ** index.js **
// declare the variable at the beginning
const { loadConfig } = require('@terran-source/dotconfig');

// load process.appConfig
let { parsed, error } = loadConfig('app-config.json');

if (error) {
  console.log(error);
}

// now either use parsed or process.appConfig (recommended)
console.log(`parsed: ${JSON.stringify(parsed, null, 2)}`);
console.log(`url: ${process.appConfig.url}`);

# execute using:
USER_NAME=DevUser USER_PASSWORD=P@ssw0rd node index.js
# output:
parsed: {
  "scheme": "http",
  "server": "localhost",
  "port": "8080",
  "baseKey": "devValue",
  "user": {
    "name": "DevUser",
    "password": "P@ssw0rd"
  },
  "url": "http://devuser:P%40ssw0rd@localhost:8080",
   "someDevKey": "someDevValue"
}
url: http://devuser:P%40ssw0rd@localhost:8080

Let's break it up:

USER_NAME & USER_PASSWORD are set through environment variable. This will replace the placeholders ${USER_NAME} & ${USER_PASSWORD} in app-config.json. The environment is not specified. Hence, it'll be set as default value dev. Now, the loadConfig function will search for any dev environment specific configuration (i.e. any file with name app-config.dev.json in the same directory, where it finds the original app-config.json). If it finds the additional file, it loads the details & overwrite anything, that matches with the base configuration or add anything, that is not present. i.e.

• "baseKey": "baseValue" becomes "baseKey": "devValue"
• additional "someDevKey": "someDevValue" key is added

To load environment specific configurations:

let { parsed, error } = loadConfig({ env: 'test', path: 'app-config.json' });
// or
let { parsed, error } = loadConfig('test', { path: 'app-config.json' });
// or
// set Environment variable `NODE_ENV=test` and then run (recommended)
let { parsed, error } = loadConfig(true, { path: 'app-config.json' });

console.log(`parsed: ${JSON.stringify(parsed, null, 2)}`);
console.log(`url: ${process.appConfig.url}`);

# execute: for  loadConfig(true, { path: 'app-config.json' })
NODE_ENV=test USER_NAME=TestUser USER_PASSWORD=P@ssw0rd node index.js
# output:
parsed: {
  "scheme": "https",
  "server": "test.example.com",
  "port": "8080",
  "baseKey": "testValue",
  "user": {
    "name": "TestUser",
    "password": "P@ssw0rd"
  },
  "url": "https://testuser:[e-mail]:8080"
}
url: https://testuser:[e-mail]:8080

env

/**
*    App Directory structure
*
*    app/
*     | -- package.json
*     | -- index.js
*     | -- .env
*     | -- dev.env
*     | -- test.env
*     | -- prod.env
*
*/

// ** .env **
key = "value"
"baseKey"= "baseValue"
'subKey'="subValue"
"someKey"= 'someValue'

// ** dev.env **
devKey=devValue
"baseKey"= "devValue"
'subKey'="subDevValue"
"someKey"= 'someDevValue'

// ** test.env **
testKey=testValue
"baseKey"= "testValue"
'subKey'="subTestValue"
"someKey"= 'someTestValue'

// ** prod.env **
"baseKey"= "${BASE_KEY}"
'subKey'="${SUB_KEY}"
"someKey"= '${SOME_KEY}'

// ** index.js **
// declare the variable at the beginning
const { loadConfig } = require('@terran-source/dotconfig');

// load process.appConfig
let { parsed, error } = loadConfig(true, { path: '.env' });

if (error) {
  console.log(error);
}

// now either use parsed or process.appConfig (recommended)
console.log(`parsed: ${JSON.stringify(parsed, null, 2)}`);
console.log(`baseKey: ${process.appConfig.baseKey}`);

For the Production environment, set the proper ENVIRONMENT_VARIABLE to be interpolated.

# execute: for  loadConfig(true, { path: '.env' })
NODE_ENV=prod BASE_KEY='some base key' SUB_KEY='some sub key' SOME_KEY='some other key' node index.js
# output:
parsed: {
  "key": "value",
  "baseKey": "some base key",
  "subKey": "some sub key",
  "someKey": "some other key"
}
baseKey: some base key

Definition

Syntax: loadConfig([true | env | file.extension], options);

The loadConfig function takes at most 2 parameters

Optional 1^st parameter

boolean: true

If the NODE_ENV environment variable is set as the environment, then passing true as first parameter signifies to get env from NODE_ENV environment value.

// ** index.js **
const { loadConfig } = require();
loadConfig(true, { path: 'app-config.json' });
// do your job
db.connect(process.appConfig.url);

# to load test config
NODE_ENV=test node index.js
# to load uat config
NODE_ENV=uat node index.js
# to load prod config
NODE_ENV=prod node index.js

environment

• example: dev, test, uat, staging, prod etc.

The application environment name, which to load the configuration file for. Should be lowercase (by tradition) & not contain any space or special character.

filename (with extension)

• example: "custom-config-file.ext"

The configuration file path (either relative or absolute).

const { loadConfig } = require('@terran-source/dotconfig');
loadConfig('app-config.json');

options

• type: json
• default:

{
  debug: false,
  encoding: 'utf8',
  env: 'dev',
  path: 'config.json',
  type: 'json'
}

more in Configurations

returns:

• type: json

{
  parsed: {}, // same as process.appConfig if succeed
  error: null // or an Error object with `message` if anything goes wrong
}

If it succeeds to load the configuration file & to parse the information containing within, it sets the process.appConfig with the value & will return with an Object with

• parsed key with the same value as process.appConfig.
• error key, which is null if succeeds or the error details if fails.

Configurations

The options setup.

debug

• type: boolean

• default: false

Set it true to turn on logging to help debug why certain things are not working as expected. Can be turned on globally.

encoding

• type: string
• default: utf8

The encoding of the configuration file, supplied in path.

env

• type: string
• default: dev

In a multi-environment setup (e.g. dev, test, uat, prod), this is the specifier for environment type. In practical case, it seems more logical to not set this one through options, but to set the NODE_ENV environment variable and pass true as first parameter to loadConfig function (see Example).

path

• type: string
• default: config.json

The path of the configuration file. It can either be a relative path or an absolute one.

type

• type: string
• default: json
• supported types: json, env

The configuration file extension.

Functions

// When declared as a variable at the beginning
const dotconfig = require('@terran-source/dotconfig');

loadConfig()

Described so far since Declaration & Definition.

// Syntax I
const dotconfig = require('@terran-source/dotconfig');
dotconfig.loadConfig(opt);

// Syntax II
const { loadConfig } = require('@terran-source/dotconfig');
loadConfig(opt);

IParser

IParser lets others to implement a custom type of parser (like toml, xml etc.)

// ** custom-parser.js **
const { IParser } = require('@terran-source/dotconfig');

// declare a class that extends IParser
class CustomParseClass extends IParser {
  constructor() {
    super();
  }

  // declare a parse function, that takes two parameters
  parse(filePath, encoding) {
    let json = // read filePath & create a json Object
    return json;
  }
}

module.exports = new CustomParseClass();

// ** somewhere.js **
const { loadConfig, setParser } = require('@terran-source/dotconfig');
const customParser = require('/path/to/custom-parser');

// define customParser for customType
setParser('customType', customParser);

// now a configuration file with extension `.customType` can be loaded
loadConfig('custom-app-config.customType');
db.connect(process.appConfig.url);

setParser()

• syntax: setParser(customType, customParser, defaultFileName = null, resetType = false)

  • customType - {type: string} It generally represents the file extension

  • customParser - {type: IParser} An IParser implementation

  • defaultFileName - {type: string, default: null} (optional) default configuration filename (without extension)

  • resetType - {type: Boolean} (optional) make the supplied customType as the default type when the config.loadConfig() runs next time

// ** somewhere.js **
const { loadConfig, setParser } = require('@terran-source/dotconfig');
const customParser = require('/path/to/custom-parser'); // custom-parser should implement IParser

// define customParser for customType & make it default
setParser('customType', customParser, 'custom-config-file', true);

// The following command now loads
//   - `custom-config-file.customType`
//   - `custom-config-file.dev.customType`
loadConfig();

// or if NODE_ENV is set to a different environment, e.g. 'test'
// it loads
//   - `custom-config-file.customType`
//   - `custom-config-file.test.customType`
loadConfig(true);

// Now process.appConfig is available
db.connect(process.appConfig.url);

debug()

Globally turn on debug flag.

// to globally turn it on
const dotconfig = require('@terran-source/dotconfig').debug();

// to globally turn off
dotconfig.debug(false);

reset()

Resets the options.

const dotconfig = require('@terran-source/dotconfig');

// do some custom job
let result = dotconfig.loadConfig({
  debug: true, // globally turn it on
  env: 'test', // globally set environment
  path: 'app-config.json', // not affecting next call
});
// start using process.appConfig or result.parsed

let result2 = dotconfig.loadConfig(); // `debug` is still set as true, `env` is still 'test', but, `path` will be default, i.e. `config.json`

// now if you want to reset debug & all other options
interpolation.reset();