KVS

KVS or Key Value Store is an abstract KeyValueStore system. The kvs group of node modules, are intended to present a unified interface to key value stores of every persuasion. This allows for substituting them without changing anything but the initializing parameters.

KVS-filter modules are modules that are used to modify the requests to the KVS system. They can transform the key or the value or both in some way. However they need to take either be transparent and keep to the KVS-system definition (i.e.: values are buffers, etc...) or be used close to the consumer of the API.

Install

npm install kvs-base

Conventions

• a valid store is an object and has 4 methods:
  • function get(name, callback) { … }
  • function set(name, callback) { … }
  • function remove(name, callback) { … }
  • function list(name, callback) { … }
• all values are Buffer objects
• the list method lists all keys that start with name (the first argument)
• the list method returns an object in the form { count:<integer>, values:[<array of strings>] }
• not finding a value is not an error, the value is simply null

Modules

Backends

• kvs-file
• kvs-memcache
• kvs-awss3

Utilities

• kvs-stagger
• kvs-segmentname
• kvs-json
• kvs-string

Use

KVS Stores

var kvs=require('kvs-base');
var store = kvs('kvs-<module>', { <options> });
store.set('name',  'this is a string', function(err) {…});
store.get('name', function(err, value) {
  // attention! value will be a string (or null if not found)
});
store.remove('name', function(err) { … });
store.list('name', function(err, value) { … });

KVS Utilities / Filters

var kvs=require('kvs-base');
var store = kvs('kvs-<module>', { <options> });
kvs.util('kvs-<filter>', store, { … });

KVS Staggering

var kvs=require('kvs-base');
var s1 = kvs('kvs-<module>', { <options> });
var s2 = kvs('kvs-<module>', { <options> });
var s3 = kvs('kvs-<module>', { <options> });
var store = kvs.util('kvs-stagger', [ s1, s2, s3 ], { writeDepth:1, removeDepth:3, percolate:false });

License (MIT)

Copyright (c) 2013 Philipp Dunkel

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.