jmptrader / go-sqlkv

An SQL-based key/value store for Golang

SQL-based key/value store for Golang

SqlKv provides an SQL-based key/value store for Golang. It can work with any of the database types supported by the built-in database/sql package.

It can be used, for example, to easily store configuration values in Sqlite, or to build a simple caching system when something more advanced like memcached or Redis is not available.

Installation

go get github.com/laurent22/go-sqlkv

Usage

The first step is to initialize a new database connection. The package expects the connection to remain open while being used. For example, using Sqlite:

db, err := sql.Open("sqlite3", "example.db")
if err != nil {
	panic(err)
}
defer db.Close()

Then create a new SqlKv object and pass it the db connection and the table name. The table will automatically be created if it does not already exist.

store := sqlkv.New(db, "kvstore")

The value can then be retrived and set using the provided methods:

• String(name) / SetString(name, value)
• Int(name) / SetInt(name, value)
• Float(name) / SetFloat(name, value)
• Bool(name) / SetBool(name, value)
• Time(name) / SetTime(name, value)

When getting a value, a default value can be provided using the alternative <Type>D() methods:

• StringD(name, "some default")
• IntD(name, 12345)
• FloatD(name, 3.14)
• BoolD(name, true)
• TimeD(name, time.Now())

In order to keep the API simple, all the errors are handled internally when possible. If an error cannot be handled (eg. cannot read or write to the database), the method will panic.

If a key is missing, each Get method will return Golang's default zero value for this type. The zero values are:

• String: ""
• Int: 0
• Float: 0
• Bool: false
• Time: time.Time{} (Test with time.IsZero())

You can use HasKey to check if a key really exists. The method Del is also available to delete a key.

Postgres support

To use the library with Postgres, you need to specify the driver name just after having created the store object:

store := sqlkv.New(db, "kvstore")
store.SetDriverName("postgres")

A more detailed example is in example/postgres/example.go

API reference

http://godoc.org/github.com/laurent22/go-sqlkv

Full example

package main

import (
	"database/sql"
	"fmt"
	"os"
	"time"
	
	_ "github.com/laurent22/go-sqlkv"
	_ "github.com/mattn/go-sqlite3"	
)

func main() {
	os.Remove("example.db")
	db, err := sql.Open("sqlite3", "example.db")
	if err != nil {
		panic(err)
	}
	defer db.Close()
	
	store := sqlkv.New(db, "kvstore")
	
	store.SetString("username", "John")
	fmt.Println(store.String("username"))
	
	store.SetInt("age", 25)
	fmt.Println(store.Int("age"))
	
	store.SetFloat("pi", 3.14)
	fmt.Println(store.Float("pi"))	

	store.SetTime("today", time.Now())
	fmt.Println(store.Time("today"))	
	
	store.SetBool("enabled", true)
	fmt.Println(store.Bool("enabled"))

	fmt.Println(store.HasKey("username"))
	
	store.Del("username")
	fmt.Println(store.String("username"))

	fmt.Println(store.HasKey("username"))	
}

License

The MIT License (MIT)

Copyright (c) 2013-2014 Laurent Cozic

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.