kv

README

KV

A simple key/value store on top of SQLite or MySQL (Go port of GitHub's KV).

Aims compatible with the original implementation by default, offering a few extra backend drivers and some extra configuration knobs.

Status

Work in progress.

• Drivers are almost feature complete.
• No optmization work has happened yet.
• Both drivers could use a few extra tests.
• API changes not expected at this point.
• Not SQL injection free

Missing functionality:

• Custom driver options for MySQL and SQLite
• setnx
• increment
• ttl
• mttl
• Configurable key/value max length
• Enforce default key and value max length

Initialization

Import the module first:

import "github.com/rubiojr/kv"

MySQL

db, err := kv.New("mysql", "root:toor@tcp(127.0.0.1:3306)/gokv")

Note that the database gokv and the table name used by default key_values will need to be created before using this driver.

USE gokv
CREATE TABLE IF NOT EXISTS key_values (
			`id` bigint(20) NOT NULL AUTO_INCREMENT,
			`key` varchar(255) NOT NULL,
			`value` blob NOT NULL,
			`created_at` datetime NOT NULL,
			`updated_at` datetime NOT NULL,
			`expires_at` datetime DEFAULT NULL,
			PRIMARY KEY (id),
			UNIQUE KEY index_key_values_on_key (`key`),
			KEY index_key_values_on_expires_at (expires_at)
			) ENGINE=InnoDB DEFAULT CHARSET=utf8

SQLite

db, err := kv.New("sqlite", "my.db")

Creates a key_values table in my.db file database to store key/values.

Getting and setting keys

Single keys:

// set a couple of keys
err = db.Set("foo", []byte("bar"), nil)
if err != nil {
	panic(err)
}
err = db.Set("stuff", []byte("staff"), nil)
if err != nil {
	panic(err)
}

// Get one key
v, err := db.Get("foo")
if err != nil {
	panic(err)
}
fmt.Println(string(v)) // prints bar

// Deleting a single key
err := db.Del("foo")
if err != nil {
	panic(err)
}

Multiple keys:

// Get multiple keys
values, err := db.MGet("foo", "staff")
if err != nil {
	panic(err)
}
// iterate the results
for _, v := range values {
	fmt.Println(string(v))
}

// Set multiple keys
values := types.KeyValues{}
values["mset1"] = "msetv1"
values["mset2"] = "msetv2"
err = db.MSet(values, nil)

// Deleting multiple keys
err := db.MDel("mset1", "mset2")
if err != nil {
	panic(err)
}

Storing binary values

An example using vmihailenco/msgpack to serialize data.

// store a string as a binary blob
b, err := msgpack.Marshal("blob")
if err != nil {
	panic(err)
}

err = db.Set("bin", b, nil)
if err != nil {
	panic(err)
}

v, err = db.Get("bin")
if err != nil {
	fmt.Println(err)
}

var blobStr string
err = msgpack.Unmarshal(b, &blobStr)
if err != nil {
	panic(err)
}
fmt.Println(blobStr)

Documentation

Index

• Constants
• type Database
  • func New(driver string, urn string) (Database, error)
• type KV

Constants

const MAX_KEY_LENGTH = 255

const MAX_VALUE_LENGTH = 65535

const TABLE_NAME = "key_values"

Types

type Database

type Database interface {
	Init(tableName string, urn string) error

	Get(key string) ([]byte, error)
	MGet(...string) ([][]byte, error)

	Set(key string, value []byte, expireAt *time.Time) error
	MSet(kvs types.KeyValues, expireAt *time.Time) error

	Del(key string) error
	MDel(keys ...string) error

	Exists(key string) (bool, error)
	MExists(keys ...string) ([]bool, error)

	Raw() *sql.DB
}

func New

func New(driver string, urn string) (Database, error)

type KV

type KV struct{}