Kiwi

A simple unified Crystal interface for key-value stores.

• Installation
• Usage
  • MemoryStore
  • FileStore
  • RedisStore
  • LevelDBStore
  • MemcachedStore
• Benchmark
• Tests
• Contributors

Installation

Add this to your application's shard.yml:

dependencies:
  kiwi:
    github: crystal-community/kiwi
    version: ~> 0.1.0

Usage

All the stores have the same simple interface defined by Kiwi::Store:

• set(key : String, value : String) : String
• get(key : String) : String|Nil
• delete(key : String) : String|Nil
• clear
• []=(key : String, value) : String - alias for set
• [](key : String) : String - alias for get

MemoryStore

require "kiwi/memory_store"

store = Kiwi::MemoryStore.new

store.set("key", "value")
store.get("key")  # => "value"
store.delete("key")
store.clear

# Or your can use Hash-like methods:
store["key"] = "new value"
store["key"]  # => "new "value"

FileStore

require "kiwi/file_store"

store = Kiwi::FileStore("/tmp/kiwi")

RedisStore

RedisStore requires you to have redis shard.

require "redis"
require "kiwi/redis_store"

store = Kiwi::RedisStore(Redis.new)

LevelDBStore

LevelDBStore requires you to have levelDB shard.

require "leveldb"
require "kiwi/leveldb_store"

leveldb = LevelDB::DB.new("./db")
store = Kiwi::LevelDBStore(leveldb)

MemcachedStore

MemcachedStore requires you to have memcached shard.

require "memcached"
require "kiwi/memcached_store"

store = Kiwi::MemcachedStore.new(Memcached::Client.new)

Benchmark

The following table shows operations per second for every particular store on my machine.

	set	get	get(empty)	delete
MemoryStore	3056000	4166000	4074000	10473000
LevelDBStore	120000	193000	253000	37000
RedisStore	41000	42000	42000	21000
MemcachedStore	38000	41000	40000	21000
FileStore	27000	66000	73000	8000

Data information:

• Key size: 5-100 bytes.
• Value size: 10-1000 bytes.
• Number of items: 100,000

Environment information:

• CPU: Intel(R) Core(TM) i7-3632QM CPU @ 2.20GHz
• File System: ext4, SSD
• RAM: DDR3, 1600 MHz
• Operating system: 3.16.0-4-amd64 x86_64 GNU/Linux

Results can vary on different systems depending on hardware(CPU, RAM, HDD/SSD) and software(OS, file system, etc).

Running benchmark

make benchmark

Tests

Run specs for all stores:

make test

Run spec for a particular store:

crystal spec ./spec/kiwi/file_store_spec.cr

Contributors

• greyblake Sergey Potapov - creator, maintainer.
• mauricioabreu Mauricio de Abreu Antunes - thanks for MemcachedStore.