nconf-lite/lib/nconf/provider.js
Matt Hamann 35088a3313 Added nconf.any method (#278)
* Added nconf.any method

Fixes #126
Implemented on the Provider class
Takes an array of keys, or a variable argument list
Supports both callback and non-callback invocations

* Use an explicit search base in file store test

Fixes #224
Test file was created under process.env.HOME, but test was searching in
the current working directory. If the cwd was not on the same drive as
the home directory, the test would fail.

* Added some API documentation to README for 'any'

* Tweak `.any` documentation
2017-10-21 16:42:24 -04:00

655 lines
17 KiB
JavaScript

/*
* provider.js: Abstraction providing an interface into pluggable configuration storage.
*
* (C) 2011, Charlie Robbins and the Contributors.
*
*/
var async = require('async'),
common = require('./common');
//
// ### function Provider (options)
// #### @options {Object} Options for this instance.
// Constructor function for the Provider object responsible
// for exposing the pluggable storage features of `nconf`.
//
var Provider = exports.Provider = function (options) {
//
// Setup default options for working with `stores`,
// `overrides`, `process.env` and `process.argv`.
//
options = options || {};
this.stores = {};
this.sources = [];
this.init(options);
};
//
// Define wrapper functions for using basic stores
// in this instance
//
['argv', 'env'].forEach(function (type) {
Provider.prototype[type] = function () {
var args = [type].concat(Array.prototype.slice.call(arguments));
return this.add.apply(this, args);
};
});
//
// ### function file (key, options)
// #### @key {string|Object} Fully qualified options, name of file store, or path.
// #### @path {string|Object} **Optional** Full qualified options, or path.
// Adds a new `File` store to this instance. Accepts the following options
//
// nconf.file({ file: '.jitsuconf', dir: process.env.HOME, search: true });
// nconf.file('path/to/config/file');
// nconf.file('userconfig', 'path/to/config/file');
// nconf.file('userconfig', { file: '.jitsuconf', search: true });
//
Provider.prototype.file = function (key, options) {
if (arguments.length == 1) {
options = typeof key === 'string' ? { file: key } : key;
key = 'file';
}
else {
options = typeof options === 'string'
? { file: options }
: options;
}
options.type = 'file';
return this.add(key, options);
};
//
// Define wrapper functions for using
// overrides and defaults
//
['defaults', 'overrides'].forEach(function (type) {
Provider.prototype[type] = function (options) {
options = options || {};
if (!options.type) {
options.type = 'literal';
}
return this.add(type, options);
};
});
//
// ### function use (name, options)
// #### @type {string} Type of the nconf store to use.
// #### @options {Object} Options for the store instance.
// Adds (or replaces) a new store with the specified `name`
// and `options`. If `options.type` is not set, then `name`
// will be used instead:
//
// provider.use('file');
// provider.use('file', { type: 'file', filename: '/path/to/userconf' })
//
Provider.prototype.use = function (name, options) {
options = options || {};
function sameOptions (store) {
return Object.keys(options).every(function (key) {
return options[key] === store[key];
});
}
var store = this.stores[name],
update = store && !sameOptions(store);
if (!store || update) {
if (update) {
this.remove(name);
}
this.add(name, options);
}
return this;
};
//
// ### function add (name, options)
// #### @name {string} Name of the store to add to this instance
// #### @options {Object} Options for the store to create
// Adds a new store with the specified `name` and `options`. If `options.type`
// is not set, then `name` will be used instead:
//
// provider.add('memory');
// provider.add('userconf', { type: 'file', filename: '/path/to/userconf' })
//
Provider.prototype.add = function (name, options, usage) {
options = options || {};
var type = options.type || name;
if (!require('../nconf')[common.capitalize(type)]) {
throw new Error('Cannot add store with unknown type: ' + type);
}
this.stores[name] = this.create(type, options, usage);
if (this.stores[name].loadSync) {
this.stores[name].loadSync();
}
return this;
};
//
// ### function remove (name)
// #### @name {string} Name of the store to remove from this instance
// Removes a store with the specified `name` from this instance. Users
// are allowed to pass in a type argument (e.g. `memory`) as name if
// this was used in the call to `.add()`.
//
Provider.prototype.remove = function (name) {
delete this.stores[name];
return this;
};
//
// ### function create (type, options)
// #### @type {string} Type of the nconf store to use.
// #### @options {Object} Options for the store instance.
// Creates a store of the specified `type` using the
// specified `options`.
//
Provider.prototype.create = function (type, options, usage) {
return new (require('../nconf')[common.capitalize(type.toLowerCase())])(options, usage);
};
//
// ### function init (options)
// #### @options {Object} Options to initialize this instance with.
// Initializes this instance with additional `stores` or `sources` in the
// `options` supplied.
//
Provider.prototype.init = function (options) {
var self = this;
//
// Add any stores passed in through the options
// to this instance.
//
if (options.type) {
this.add(options.type, options);
}
else if (options.store) {
this.add(options.store.name || options.store.type, options.store);
}
else if (options.stores) {
Object.keys(options.stores).forEach(function (name) {
var store = options.stores[name];
self.add(store.name || name || store.type, store);
});
}
//
// Add any read-only sources to this instance
//
if (options.source) {
this.sources.push(this.create(options.source.type || options.source.name, options.source));
}
else if (options.sources) {
Object.keys(options.sources).forEach(function (name) {
var source = options.sources[name];
self.sources.push(self.create(source.type || source.name || name, source));
});
}
};
//
// ### function get (key, callback)
// #### @key {string} Key to retrieve for this instance.
// #### @callback {function} **Optional** Continuation to respond to when complete.
// Retrieves the value for the specified key (if any).
//
Provider.prototype.get = function (key, callback) {
if (typeof key === 'function') {
// Allow a * key call to be made
callback = key;
key = null;
}
//
// If there is no callback we can short-circuit into the default
// logic for traversing stores.
//
if (!callback) {
return this._execute('get', 1, key, callback);
}
//
// Otherwise the asynchronous, hierarchical `get` is
// slightly more complicated because we do not need to traverse
// the entire set of stores, but up until there is a defined value.
//
var current = 0,
names = Object.keys(this.stores),
self = this,
response,
mergeObjs = [];
async.whilst(function () {
return typeof response === 'undefined' && current < names.length;
}, function (next) {
var store = self.stores[names[current]];
current++;
if (store.get.length >= 2) {
return store.get(key, function (err, value) {
if (err) {
return next(err);
}
response = value;
// Merge objects if necessary
if (response && typeof response === 'object' && !Array.isArray(response)) {
mergeObjs.push(response);
response = undefined;
}
next();
});
}
response = store.get(key);
// Merge objects if necessary
if (response && typeof response === 'object' && !Array.isArray(response)) {
mergeObjs.push(response);
response = undefined;
}
next();
}, function (err) {
if (!err && mergeObjs.length) {
response = common.merge(mergeObjs.reverse());
}
return err ? callback(err) : callback(null, response);
});
};
//
// ### function any (keys, callback)
// #### @keys {array|string...} Array of keys to query, or a variable list of strings
// #### @callback {function} **Optional** Continuation to respond to when complete.
// Retrieves the first truthy value (if any) for the specified list of keys.
//
Provider.prototype.any = function (keys, callback) {
if (!Array.isArray(keys)) {
keys = Array.prototype.slice.call(arguments);
if (keys.length > 0 && typeof keys[keys.length - 1] === 'function') {
callback = keys.pop();
} else {
callback = null;
}
}
//
// If there is no callback, use the short-circuited "get"
// on each key in turn.
//
if (!callback) {
var val;
for (var i = 0; i < keys.length; ++i) {
val = this._execute('get', 1, keys[i], callback);
if (val) {
return val;
}
}
return null;
}
var keyIndex = 0,
result,
self = this;
async.whilst(function() {
return !result && keyIndex < keys.length;
}, function(next) {
var key = keys[keyIndex];
keyIndex++;
self.get(key, function(err, v) {
if (err) {
next(err);
} else {
result = v;
next();
}
});
}, function(err) {
return err ? callback(err) : callback(null, result);
});
};
//
// ### function set (key, value, callback)
// #### @key {string} Key to set in this instance
// #### @value {literal|Object} Value for the specified key
// #### @callback {function} **Optional** Continuation to respond to when complete.
// Sets the `value` for the specified `key` in this instance.
//
Provider.prototype.set = function (key, value, callback) {
return this._execute('set', 2, key, value, callback);
};
//
// ### function required (keys)
// #### @keys {array} List of keys
// Throws an error if any of `keys` has no value, otherwise returns `true`
Provider.prototype.required = function (keys) {
if (!Array.isArray(keys)) {
throw new Error('Incorrect parameter, array expected');
}
var missing = [];
keys.forEach(function(key) {
if (typeof this.get(key) === 'undefined') {
missing.push(key);
}
}, this);
if (missing.length) {
throw new Error('Missing required keys: ' + missing.join(', '));
} else {
return true;
}
};
//
// ### function reset (callback)
// #### @callback {function} **Optional** Continuation to respond to when complete.
// Clears all keys associated with this instance.
//
Provider.prototype.reset = function (callback) {
return this._execute('reset', 0, callback);
};
//
// ### function clear (key, callback)
// #### @key {string} Key to remove from this instance
// #### @callback {function} **Optional** Continuation to respond to when complete.
// Removes the value for the specified `key` from this instance.
//
Provider.prototype.clear = function (key, callback) {
return this._execute('clear', 1, key, callback);
};
//
// ### function merge ([key,] value [, callback])
// #### @key {string} Key to merge the value into
// #### @value {literal|Object} Value to merge into the key
// #### @callback {function} **Optional** Continuation to respond to when complete.
// Merges the properties in `value` into the existing object value at `key`.
//
// 1. If the existing value `key` is not an Object, it will be completely overwritten.
// 2. If `key` is not supplied, then the `value` will be merged into the root.
//
Provider.prototype.merge = function () {
var self = this,
args = Array.prototype.slice.call(arguments),
callback = typeof args[args.length - 1] === 'function' && args.pop(),
value = args.pop(),
key = args.pop();
function mergeProperty (prop, next) {
return self._execute('merge', 2, prop, value[prop], next);
}
if (!key) {
if (Array.isArray(value) || typeof value !== 'object') {
return onError(new Error('Cannot merge non-Object into top-level.'), callback);
}
return async.forEach(Object.keys(value), mergeProperty, callback || function () { })
}
return this._execute('merge', 2, key, value, callback);
};
//
// ### function load (callback)
// #### @callback {function} Continuation to respond to when complete.
// Responds with an Object representing all keys associated in this instance.
//
Provider.prototype.load = function (callback) {
var self = this;
function getStores () {
var stores = Object.keys(self.stores);
stores.reverse();
return stores.map(function (name) {
return self.stores[name];
});
}
function loadStoreSync(store) {
if (!store.loadSync) {
throw new Error('nconf store ' + store.type + ' has no loadSync() method');
}
return store.loadSync();
}
function loadStore(store, next) {
if (!store.load && !store.loadSync) {
return next(new Error('nconf store ' + store.type + ' has no load() method'));
}
return store.loadSync
? next(null, store.loadSync())
: store.load(next);
}
function loadBatch (targets, done) {
if (!done) {
return common.merge(targets.map(loadStoreSync));
}
async.map(targets, loadStore, function (err, objs) {
return err ? done(err) : done(null, common.merge(objs));
});
}
function mergeSources (data) {
//
// If `data` was returned then merge it into
// the system store.
//
if (data && typeof data === 'object') {
self.use('sources', {
type: 'literal',
store: data
});
}
}
function loadSources () {
var sourceHierarchy = self.sources.splice(0);
sourceHierarchy.reverse();
//
// If we don't have a callback and the current
// store is capable of loading synchronously
// then do so.
//
if (!callback) {
mergeSources(loadBatch(sourceHierarchy));
return loadBatch(getStores());
}
loadBatch(sourceHierarchy, function (err, data) {
if (err) {
return callback(err);
}
mergeSources(data);
return loadBatch(getStores(), callback);
});
}
return self.sources.length
? loadSources()
: loadBatch(getStores(), callback);
};
//
// ### function save (callback)
// #### @callback {function} **optional** Continuation to respond to when
// complete.
// Instructs each provider to save. If a callback is provided, we will attempt
// asynchronous saves on the providers, falling back to synchronous saves if
// this isn't possible. If a provider does not know how to save, it will be
// ignored. Returns an object consisting of all of the data which was
// actually saved.
//
Provider.prototype.save = function (value, callback) {
if (!callback && typeof value === 'function') {
callback = value;
value = null;
}
var self = this,
names = Object.keys(this.stores);
function saveStoreSync(memo, name) {
var store = self.stores[name];
//
// If the `store` doesn't have a `saveSync` method,
// just ignore it and continue.
//
if (store.saveSync) {
var ret = store.saveSync();
if (typeof ret == 'object' && ret !== null) {
memo.push(ret);
}
}
return memo;
}
function saveStore(memo, name, next) {
var store = self.stores[name];
//
// If the `store` doesn't have a `save` or saveSync`
// method(s), just ignore it and continue.
//
if (store.save) {
return store.save(value, function (err, data) {
if (err) {
return next(err);
}
if (typeof data == 'object' && data !== null) {
memo.push(data);
}
next(null, memo);
});
}
else if (store.saveSync) {
memo.push(store.saveSync());
}
next(null, memo);
}
//
// If we don't have a callback and the current
// store is capable of saving synchronously
// then do so.
//
if (!callback) {
return common.merge(names.reduce(saveStoreSync, []));
}
async.reduce(names, [], saveStore, function (err, objs) {
return err ? callback(err) : callback(null, common.merge(objs));
});
};
//
// ### @private function _execute (action, syncLength, [arguments])
// #### @action {string} Action to execute on `this.store`.
// #### @syncLength {number} Function length of the sync version.
// #### @arguments {Array} Arguments array to apply to the action
// Executes the specified `action` on all stores for this instance, ensuring a callback supplied
// to a synchronous store function is still invoked.
//
Provider.prototype._execute = function (action, syncLength /* [arguments] */) {
var args = Array.prototype.slice.call(arguments, 2),
callback = typeof args[args.length - 1] === 'function' && args.pop(),
destructive = ['set', 'clear', 'merge', 'reset'].indexOf(action) !== -1,
self = this,
response,
mergeObjs = [],
keys = Object.keys(this.stores);
function runAction (name, next) {
var store = self.stores[name];
if (destructive && store.readOnly) {
return next();
}
return store[action].length > syncLength
? store[action].apply(store, args.concat(next))
: next(null, store[action].apply(store, args));
}
if (callback) {
return async.forEach(keys, runAction, function (err) {
return err ? callback(err) : callback();
});
}
keys.forEach(function (name) {
if (typeof response === 'undefined') {
var store = self.stores[name];
if (destructive && store.readOnly) {
return;
}
response = store[action].apply(store, args);
// Merge objects if necessary
if (response && action === 'get' && typeof response === 'object' && !Array.isArray(response)) {
mergeObjs.push(response);
response = undefined;
}
}
});
if (mergeObjs.length) {
response = common.merge(mergeObjs.reverse());
}
return response;
}
//
// Throw the `err` if a callback is not supplied
//
function onError(err, callback) {
if (callback) {
return callback(err);
}
throw err;
}