sharder

Generate 128 bits keys and resolve them to shards

sharder  

Generate 128 bits keys and resolve them to shards. A shard can be just any JS object.

$ npm install sharder --save

 
var shard1  = { url: 'http://localhost:3000', append: true }
  , shard2  = { url: 'http://localhost:3001', append: true }
  , shard3  = { url: 'http://localhost:3002', append: false }
  , sharder = require('sharder')({
                shards: {
                    1: shard1
                  , 2: shard2
                  , 3: shard3
                }
              })
 
  , key     = sharder.generate()
 
  , cacher = require('sharder')({
                cache: true,
                shards: {
                    1: shard1
                  , 2: shard2
                }
              })
 
console.log(sharder.resolve(key))
// { url: 'http://localhost:3000', append: true, id: 1 } 
console.log(sharder.resolve(key))
// { url: 'http://localhost:3000', append: true, id: 1 } 
console.log(sharder.resolve(key))
// { url: 'http://localhost:3000', append: true, id: 1 } 
 
console.log(cacher.generate(new Buffer([1, 2])))
// 01000000-0000-0000-0000-000000000102 
console.log(cacher.generate(new Buffer([1, 2])))
// 01000000-0000-0000-0000-000000000102 
console.log(cacher.generate(new Buffer([3, 2])))
// 02000000-0000-0000-0000-000000000302 
console.log(cacher.generate(new Buffer([3, 2])))
// 02000000-0000-0000-0000-000000000302 

Sharder is the class and function exposed by this module. It can be created by sharder() or using new Sharder().

A sharder accepts the following options:

  • shards: contains a map of shards, identified by a number.
  • cache: enables cache mode, in this mode all shards must be appendable and generate must be used with a fixed prefix.

Every shard might include a append: true property, to identify it is writable. This property is defaulted to true.

Example

new Sharder({
  shards: {
      1: {
          append: false
        , url: 'http://localhost:3001'
      }
    , 2: {
          append: true
        , url: 'http://localhost:3002'
      }
    , 3: {
          append: true
        , url: 'http://localhost:3003'
      }
  }
})

Generate a uuid-style identifier.

If the sharder is initialized with cache: true the fixedPart is mandatory, and the id is calculated based on the number of bits in the fixedPart.


Resolve a key generated by generate() to a specific shard.

Copyright (c) 2014, Matteo Collina hello@matteocollina.com

Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.