nconf-lite/lib/nconf/stores/redis.js

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/*
* redis.js: Redis storage engine for nconf configuration(s)
*
* (C) 2011, Charlie Robbins
*
*/
var async = require('async'),
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eyes = require('eyes'),
redis = require('redis'),
nconf = require('nconf'),
Memory = require('./Memory').Memory;
//
// ### function Redis (options)
// #### @options {Object} Options for this instance
// Constructor function for the Redis nconf store which maintains
// a nested Redis key structure based on key delimiters `:`.
//
// e.g.
// my:nested:key, 'value'
// namespace:keys ==> ['my']
// namespace:nested:keys ==> ['key']
// namespace:nested:key ==> 'value'
//
var Redis = exports.Redis = function (options) {
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options = options || {}
this.namespace = options.namespace || 'nconf';
this.host = options.host || 'localhost';
this.port = options.port || 6379;
this.ttl = options.ttl || 60 * 60 * 1000;
this.cache = new Memory();
this.redis = redis.createClient(options.port, options.host);
};
//
// ### function get (key, callback)
// #### @key {string} Key to retrieve for this instance.
// #### @callback {function} Continuation to respond to when complete.
// Retrieves the value for the specified key (if any).
//
Redis.prototype.get = function (key, callback) {
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var self = this,
result = {},
now = Date.now(),
mtime = this.cache.mtimes[key],
fullKey = nconf.key(this.namespace, key);
//
// If the key exists in the cache and the ttl is less than
// the value set for this instance, return from the cache.
//
if (mtime && now - mtime < this.ttl) {
return callback(null, this.cache.get(key));
}
//
// Get the set of all children keys for the `key` supplied. If the value
// to be returned is an Object, this list will not be empty.
//
this.redis.smembers(nconf.key(fullKey, 'keys'), function (err, keys) {
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function addValue (source, next) {
self.get(nconf.key(key, source), function (err, value) {
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if (err) {
return next(err);
}
result[source] = value;
next();
});
}
if (keys && keys.length > 0) {
//
// If the value to be retrieved is an Object, recursively attempt
// to get the value from redis. Here we use a recursive call to `this.get`
// to support nested Object keys.
//
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async.forEach(keys, addValue, function (err) {
if (err) {
return callback(err);
}
self.cache.set(key, result);
callback(null, result);
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})
}
else {
//
// If there are no keys, then the value to be retrieved is a literal
// and we can simply return the value from redis directly.
//
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self.redis.get(fullKey, function (err, value) {
if (err) {
return callback(err);
}
result = JSON.parse(value);
if (result) {
self.cache.set(key, result);
}
callback(null, result);
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});
}
});
};
//
// ### function set (key, value, callback)
// #### @key {string} Key to set in this instance
// #### @value {literal|Object} Value for the specified key
// #### @callback {function} Continuation to respond to when complete.
// Sets the `value` for the specified `key` in this instance.
//
Redis.prototype.set = function (key, value, callback) {
var self = this,
path = nconf.path(key);
function addKey (partial, next) {
var index = path.indexOf(partial),
base = [self.namespace].concat(path.slice(0, index)),
parent = nconf.key.apply(null, base.concat(['keys']));
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self.redis.sadd(parent, partial, next);
};
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//
// Iterate over the entire key path and add each key to the
// parent key-set if it doesn't exist already.
//
async.forEach(path, addKey, function (err) {
if (err) {
return callback(err);
}
var fullKey = nconf.key(self.namespace, key);
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if (!Array.isArray(value) && typeof value === 'object') {
//
// If the value is an `Object` (and not an `Array`) then
// nest into the value and set the child keys appropriately.
// This is done for efficient lookup when setting Object keys.
// (i.e. If you set and Object then wish to later retrieve only a
// member of that Object, the entire Object need not be retrieved).
//
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self._setObject(fullKey, value, callback);
}
else {
//
// If the value is a simple literal (or an `Array`) then JSON
// stringify it and put it into Redis.
//
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value = JSON.stringify(value);
self.cache.set(key, value);
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self.redis.set(fullKey, value, callback);
}
});
};
//
// ### function clear (key, callback)
// #### @key {string} Key to remove from this instance
// #### @callback {function} Continuation to respond to when complete.
// Removes the value for the specified `key` from this instance.
//
Redis.prototype.clear = function (key, callback) {
var self = this,
result = {},
path = [this.namespace].concat(nconf.path(key)),
last = path.pop(),
fullKey = nconf.key(this.namespace, key);
//
// Clear the key from the cache for this instance
//
this.cache.clear(key);
//
// Remove the `key` from the parent set of keys.
//
this.redis.srem(nconf.key.apply(null, path.concat(['keys'])), last, function (err) {
//
// Remove the value from redis by iterating over the set of keys (if any)
// and deleting each value. If no keys, then just delete the simple literal.
//
self.redis.smembers(nconf.key(fullKey, 'keys'), function (err, keys) {
function removeValue (child, next) {
//
// Recursively call `self.clear` here to ensure we remove any
// nested Objects completely from this instance.
//
self.clear(nconf.key(key, child), next);
}
if (keys && keys.length > 0) {
//
// If there are child keys then iterate over them,
// removing each child along the way.
//
async.forEach(keys, removeValue, callback);
}
else {
//
// Otherwise if this is just a simple literal, then
// simply remove it from Redis directly.
//
self.redis.del(fullKey, callback);
}
});
});
};
//
// ### function save (value, callback)
// #### @value {Object} Config object to set for this instance
// #### @callback {function} Continuation to respond to when complete.
// Removes any existing configuration settings that may exist in this
// instance and then adds all key-value pairs in `value`.
//
Redis.prototype.save = function (value, callback) {
if (Array.isArray(value) || typeof value !== 'object') {
return callback(new Error('`value` to be saved must be an object.'));
}
var self = this,
keys = Object.keys(value);
//
// Clear all existing keys associated with this instance.
//
this.reset(function (err) {
if (err) {
return callback(err);
}
//
// Iterate over the keys in the new value, setting each of them.
//
async.forEach(keys, function (key, next) {
self.set(key, value[key], next);
}, callback);
});
};
//
// ### function load (callback)
// #### @callback {function} Continuation to respond to when complete.
// Responds with an Object representing all keys associated in this instance.
//
Redis.prototype.load = function (callback) {
var self = this,
result = {};
this.redis.smembers(nconf.key(this.namespace, 'keys'), function (err, keys) {
if (err) {
return callback(err);
}
function addValue (key, next) {
self.get(key, function (err, value) {
if (err) {
return next(err);
}
result[key] = value;
next();
});
}
async.forEach(keys, addValue, function (err) {
return err ? callback(err) : callback(null, result);
});
});
};
//
// ### function reset (callback)
// #### @callback {function} Continuation to respond to when complete.
// Clears all keys associated with this instance.
//
Redis.prototype.reset = function (callback) {
var self = this;
//
// Get the list of of top-level keys, then clear each of them
//
this.redis.smembers(nconf.key(this.namespace, 'keys'), function (err, existing) {
if (err) {
return callback(err);
}
async.forEach(existing, function (key, next) {
self.clear(key, next);
}, callback);
});
};
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//
// ### @private function _setObject (key, value, callback)
// #### @key {string} Key to set in this instance
// #### @value {Object} Value for the specified key
// #### @callback {function} Continuation to respond to when complete.
// Internal helper function for setting all keys of a nested object.
//
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Redis.prototype._setObject = function (key, value, callback) {
var self = this,
keys = Object.keys(value);
function addValue (child, next) {
//
// Add the child key to the parent key-set, then set the value.
// Recursively call `_setObject` in the event of nested Object(s).
//
self.redis.sadd(nconf.key(key, 'keys'), child, function (err) {
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if (err) {
return next(err);
}
var fullKey = nconf.key(key, child),
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childValue = value[child];
if (!Array.isArray(childValue) && typeof childValue === 'object') {
self._setObject(fullKey, childValue, next);
}
else {
childValue = JSON.stringify(childValue);
self.redis.set(fullKey, childValue, next);
}
});
}
//
// Iterate over the keys of the Object and set the appropriate values.
//
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async.forEach(keys, addValue, function (err) {
return err ? callback(err) : callback();
});
};