crampon

Hierarchical configuration, made easy.

Basic Usage (No Hierarchy)

In it's most basic usage, you can add configuration objects to a crampon instance and then access that configuration:

var Crampon = require('crampon'),
    crampon = new Crampon().add({
        root: '/home/apps/ftknox'
    });

var config = crampon.getConfig();

Adding Data

Data can be added using the add and addFile methods. New data is merged with old data and if there are conflicts then new values will take precedence:

var crampon = new Crampon().add({
        root: '/home/apps/ftknox',
        db: {
            name: 'ftknox',
            pwd: '1234'
        }
    })
    .addFile('./conf'); // could be conf.js or conf.json if extension is not specified

// conf.js: module.exports = { db: { pwd:'abcd' } };

assert.deepEqual(crampon.getConfig(), {
    root: '/home/apps/ftknox',
    db: {
        name: 'ftknox',
        pwd: 'abcd'
    }
});

Hierarchical Configuration

Hierarchical configuration can be used to setup environment specific configuration with the ability to inherit and override configuration for each environment:

// Set the hierarchy when constructing an instance of crampon
var crampon = new Crampon(['prod', 'test', 'dev']).add({
    prod: {
        root: '/home/apps/ftknox',
        db: {
            name: 'ftknox',
            pwd: '1234'
        },
        debugLevel: 3
    },
    stage: {
        debugLevel: 2
    },
    dev: {
        db: {
            name: 'ftknox_dev'
        },
        debugLevel: 1
    }
});

// Get the dev configuration
var config = crampon.getConfig('dev');

// Note that the environment param defaults to the NODE_ENV environment variable

assert.deepEqual(config, {
    root: '/home/apps/ftknox',
    db: {
        name: 'ftknox_dev',
        pwd: '1234'
    },
    debugLevel: 3
});

Overrides

When using a hierarchical configuration, data added via add and addFile must have environment keys at the root. In order to override environment specific configuration with configuration that applies in all cases you can use addOverride and addOverrideFile.

Continuing the above example, you could override the debugLevel in your dev environment in this way:

crampon.addOverride({
    debugLevel: 1
});

// Get the configuration
var config = crampon.getConfig('dev');

// debugLevel is now 1 in all environments
assert.deepEqual(config, {
    root: '/home/apps/ftknox',
    db: {
        name: 'ftknox_dev',
        pwd: '1234'
    },
    debugLevel: 1
});

Arrays

As of version 0.2, arrays in configuration are replaced, rather than merged.

var crampon = new Crampon().add({
        favoriteColor: 'pink',
        otherColors: [
            'blue',
            'red'
        ]
    })
    .add({
        otherColors: [
            'green',
            'black'
        ]
    });

assert.deepEqual(crampon.getConfig(), {
    favoriteColor: 'pink',
    otherColors: [
        'green',
        'black'
    ]
});