nconf
Forked to make nconf.argv more testable
Hierarchical node.js configuration with files, environment variables, command-line arguments, and atomic object merging.
Example
Using nconf is easy; it is designed to be a simple key-value store with support for both local and remote storage. Keys are namespaced and delimited by :
. Let's dive right into sample usage:
var fs = require('fs'),
nconf = require('nconf');
//
// Setup nconf to use (in-order):
// 1. Command-line arguments
// 2. Environment variables
// 3. A file located at 'path/to/config.json'
//
nconf.argv()
.env()
.file({ file: 'path/to/config.json' });
//
// Set a few variables on `nconf`.
//
nconf.set('database:host', '127.0.0.1');
nconf.set('database:port', 5984);
//
// Get the entire database object from nconf. This will output
// { host: '127.0.0.1', port: 5984 }
//
console.log('foo: ' + nconf.get('foo'));
console.log('NODE_ENV: ' + nconf.get('NODE_ENV'));
console.log('database: ' + nconf.get('database'));
//
// Save the configuration object to disk
//
nconf.save(function (err) {
fs.readFile('path/to/your/config.json', function (err, data) {
console.dir(JSON.parse(data.toString()))
});
});
If you run the above script:
$ NODE_ENV=production sample.js --foo bar
The output will be:
foo: bar
NODE_ENV: production
database: { host: '127.0.0.1', port: 5984 }
Hierarchical configuration
Configuration management can get complicated very quickly for even trivial applications running in production. nconf
addresses this problem by enabling you to setup a hierarchy for different sources of configuration with no defaults. The order in which you attach these configuration sources determines their priority in the hierarchy. Let's take a look at the options available to you
-
nconf.argv(options) Loads
process.argv
using yargs. Ifoptions
is supplied it is passed along to yargs. -
nconf.env(options) Loads
process.env
into the hierarchy. - nconf.file(options) Loads the configuration data at options.file into the hierarchy.
- nconf.defaults(options) Loads the data in options.store into the hierarchy.
- nconf.overrides(options) Loads the data in options.store into the hierarchy.
A sane default for this could be:
var nconf = require('nconf');
//
// 1. any overrides
//
nconf.overrides({
'always': 'be this value'
});
//
// 2. `process.env`
// 3. `process.argv`
//
nconf.env().argv();
//
// 4. Values in `config.json`
//
nconf.file('/path/to/config.json');
//
// Or with a custom name
// Note: A custom key must be supplied for hierarchy to work if multiple files are used.
//
nconf.file('custom', '/path/to/config.json');
//
// Or searching from a base directory.
// Note: `name` is optional.
//
nconf.file(name, {
file: 'config.json',
dir: 'search/from/here',
search: true
});
//
// 5. Any default values
//
nconf.defaults({
'if nothing else': 'use this value'
});
API Documentation
The top-level of nconf
is an instance of the nconf.Provider
abstracts this all for you into a simple API.
nconf.add(name, options)
Adds a new store with the specified name
and options
. If options.type
is not set, then name
will be used instead:
nconf.add('supplied', { type: 'literal', store: { 'some': 'config' });
nconf.add('user', { type: 'file', file: '/path/to/userconf.json' });
nconf.add('global', { type: 'file', file: '/path/to/globalconf.json' });
nconf.use(name, options)
Similar to nconf.add
, except that it can replace an existing store if new options are provided
//
// Load a file store onto nconf with the specified settings
//
nconf.use('file', { file: '/path/to/some/config-file.json' });
//
// Replace the file store with new settings
//
nconf.use('file', { file: 'path/to/a-new/config-file.json' });
nconf.remove(name)
Removes the store with the specified name.
The configuration stored at that level will no longer be used for lookup(s).
nconf.remove('file');
nconf.required(keys)
Declares a set of string keys to be mandatory, and throw an error if any are missing.
nconf.defaults({
keya: 'a',
});
nconf.required(['keya', 'keyb']);
// Error: Missing required keys: keyb
Storage Engines
Memory
A simple in-memory storage engine that stores a nested JSON representation of the configuration. To use this engine, just call .use()
with the appropriate arguments. All calls to .get()
, .set()
, .clear()
, .reset()
methods are synchronous since we are only dealing with an in-memory object.
nconf.use('memory');
Argv
Responsible for loading the values parsed from process.argv
by yargs
into the configuration hierarchy. See the yargs option docs for more on the option format.
//
// Can optionally also be an object literal to pass to `yargs`.
//
nconf.argv({
"x": {
alias: 'example',
describe: 'Example description for usage generation',
demand: true,
default: 'some-value'
}
});
Env
Responsible for loading the values parsed from process.env
into the configuration hierarchy.
//
// Can optionally also be an Array of values to limit process.env to.
//
nconf.env(['only', 'load', 'these', 'values', 'from', 'process.env']);
//
// Can also specify a separator for nested keys (instead of the default ':')
//
nconf.env('__');
// Get the value of the env variable 'database__host'
var dbHost = nconf.get('database:host');
//
// Or use all options
//
nconf.env({
separator: '__',
match: /^whatever_matches_this_will_be_whitelisted/
whitelist: ['database__host', 'only', 'load', 'these', 'values', 'if', 'whatever_doesnt_match_but_is_whitelisted_gets_loaded_too']
});
var dbHost = nconf.get('database:host');
Literal
Loads a given object literal into the configuration hierarchy. Both nconf.defaults()
and nconf.overrides()
use the Literal store.
nconf.defaults({
'some': 'default value'
});
File
Based on the Memory store, but provides additional methods .save()
and .load()
which allow you to read your configuration to and from file. As with the Memory store, all method calls are synchronous with the exception of .save()
and .load()
which take callback functions.
It is important to note that setting keys in the File engine will not be persisted to disk until a call to .save()
is made. Note a custom key must be supplied as the first parameter for hierarchy to work if multiple files are used.
nconf.file('path/to/your/config.json');
// add multiple files, hierarchically. notice the unique key for each file
nconf.file('user', 'path/to/your/user.json');
nconf.file('global', 'path/to/your/global.json');
The file store is also extensible for multiple file formats, defaulting to JSON
. To use a custom format, simply pass a format object to the .use()
method. This object must have .parse()
and .stringify()
methods just like the native JSON
object.
If the file does not exist at the provided path, the store will simply be empty.
Encrypting file contents
As of nconf@0.8.0
it is now possible to encrypt and decrypt file contents using the secure
option:
nconf.file('secure-file', {
file: 'path/to/secure-file.json',
secure: {
secret: 'super-secretzzz-keyzz',
alg: 'aes-256-ctr'
}
})
This will encrypt each key using crypto.createCipher
, defaulting to aes-256-ctr
. The encrypted file contents will look like this:
{
"config-key-name": {
"alg": "aes-256-ctr", // cipher used
"value": "af07fbcf" // encrypted contents
},
"another-config-key": {
"alg": "aes-256-ctr", // cipher used
"value": "e310f6d94f13" // encrypted contents
},
}
Redis
There is a separate Redis-based store available through nconf-redis. To install and use this store simply:
$ npm install nconf
$ npm install nconf-redis
Once installing both nconf
and nconf-redis
, you must require both modules to use the Redis store:
var nconf = require('nconf');
//
// Requiring `nconf-redis` will extend the `nconf`
// module.
//
require('nconf-redis');
nconf.use('redis', { host: 'localhost', port: 6379, ttl: 60 * 60 * 1000 });
Installation
npm install nconf --save
Run Tests
Tests are written in vows and give complete coverage of all APIs and storage engines.
$ npm test