DynamicConfig

Dynamic configuration storage that can use files and/or environment.

Different sets of configuration can be used.

If present, a default configuration file will always be merged without overwriting previous data.

Installation

Installing from NPM

npm install @codedv8/dynamicconfig --save

Installing from GitHub

npm install https://github.com/codedeviate/dynamicconfig.git --save

Typescript

Batteries are included.

This module contains a typescript declaration.

Fused entries

Keys can be protected by a fuse.

A fused key can't have its value changed by calling the set function.

After calling the function setBlowOnFuse any attempt to set a fused value will result in throwing an exception. This value can not be unset.

const dynConf = require('@codedv8/dynamicconfig');
...
dynConf.addFuse('fused.value');
...
dynConf.set('fused.value', 'new value');

This will result in throwing an exception.

const dynConf = require('@codedv8/dynamicconfig');
...
dynConf.addFuse('fused.value');
...
dynConf.set('fused.value', 'new value');

This will just return quietly without changing any values.

Fallback and default configuration

First of all a configuration matching the enviroment will be loaded. After that the module will search for a default configuration that will be merged without overwriting existing data.

Usage

Force type of config

CONFIG_TYPE=ini node example/basic.js

This will only use files with an ini extention

Set execution environment

NODE_ENV=development node example/basic.js

This will use a config files named development.*. If none is found it will still try to find a config file named default.*.

Set execution environment and force type of config

NODE_ENV=development CONFIG_TYPE=json node example/basic.js

This will use a config files named development.json. If none is found it will still try to find a config file named default.json.

Code usage

Output the current configuration

const devConf = require('@codedv8/dynamicconfig');
console.log(JSON.stringify(devConf.get(), null, '  '));

Get PORT with default value 3070

const devConf = require('@codedv8/dynamicconfig');
const PORT = devConf.get('PORT', 3070);

Get and set values without fuse and with fuse

const devConf = require('@codedv8/dynamicconfig');
console.log('PORT :', devConf.get('PORT', 3070));
devConf.set('PORT', 3071);
console.log('PORT :', devConf.get('PORT', 3070));
devConf.addFuse('PORT');
console.log('PORT :', devConf.get('PORT', 3070));
devConf.set('PORT', 3072);
console.log('PORT :', devConf.get('PORT', 3070));

This will print

PORT : 3070
PORT : 3071
PORT : 3071
PORT : 3071

Get and set values without fuse and with fuse where fuses are set to blow

const devConf = require('@codedv8/dynamicconfig');
devConf.setBlowOnFuse();
console.log('PORT :', devConf.get('PORT', 3070));
devConf.set('PORT', 3071);
console.log('PORT :', devConf.get('PORT', 3070));
devConf.addFuse('PORT');
console.log('PORT :', devConf.get('PORT', 3070));
devConf.set('PORT', 3072);
console.log('PORT :', devConf.get('PORT', 3070));

This will print

PORT : 3070
PORT : 3071
PORT : 3071
/xxxx/xxxx/xxxx/dynamicconfig/index.js:XXX
        throw new Error(`Key ${key} is fused`);
        ^
Error: Key PORT is fused
...

Examples in TypeScript

Get PORT with default value 3070

import devConf from '@codedv8/dynamicconfig'

const PORT = devConf.get('PORT', 3070)

Functions

get(key, defaultValue = null, throwOnDefault = false): value

Will try to find the key from the environment or the config (in that order). If the key isn't found then the default value will be returned. If not default value has been supplied then null will be retruned.

If the parameter throwOnDefault is set to true then an exception will be thrown if the key isn't found.

If the key is omitted (or set to undefined) the config object wil be returned.