Redsync

Redsync provides a Redis-based distributed mutual exclusion lock implementation for Go as described in this post. A reference library (by antirez) for Ruby is available at github.com/antirez/redlock-rb.

Installation

Install Redsync using the go get command:

$ go get github.com/go-redsync/redsync/v4

Two driver implementations will be installed; however, only the one used will be included in your project.

See the examples folder for usage of each driver.

Documentation

Reference

Usage

Error handling is simplified to panic for shorter example.

package main

import (
	goredislib "github.com/redis/go-redis/v9"
	"github.com/go-redsync/redsync/v4"
	"github.com/go-redsync/redsync/v4/redis/goredis/v9"
)

func main() {
	// Create a pool with go-redis (or redigo) which is the pool redisync will
	// use while communicating with Redis. This can also be any pool that
	// implements the `redis.Pool` interface.
	client := goredislib.NewClient(&goredislib.Options{
		Addr: "localhost:6379",
	})
	pool := goredis.NewPool(client) // or, pool := redigo.NewPool(...)

	// Create an instance of redisync to be used to obtain a mutual exclusion
	// lock.
	rs := redsync.New(pool)

	// Obtain a new mutex by using the same name for all instances wanting the
	// same lock.
	mutexname := "my-global-mutex"
	mutex := rs.NewMutex(mutexname)

	// Obtain a lock for our given mutex. After this is successful, no one else
	// can obtain the same lock (the same mutex name) until we unlock it.
	if err := mutex.Lock(); err != nil {
		panic(err)
	}

	// Do your work that requires the lock.

	// Release the lock so other processes or threads can obtain a lock.
	if ok, err := mutex.Unlock(); !ok || err != nil {
		panic("unlock failed")
	}
}

Contributing

Contributions are welcome.

License

Redsync is available under the BSD (3-Clause) License.

Disclaimer

This code implements an algorithm which is currently a proposal, it was not formally analyzed. Make sure to understand how it works before using it in production environments.

Real World Uses

Below is a list of public, open source projects that use Redsync:

Sourcegraph: Universal code search and intelligence platform. Uses Redsync in an internal cache implementation.
Open Match by Google: Flexible, extensible, and scalable video game matchmaking. Uses Redsync with its state store implementation.
Gocron by go-co-op: gocron is a job distributed scheduling package which lets you run Go functions at pre-determined intervals using a simple, human-friendly syntax. Uses Redsync with its distributed job scheduler implementation.

If you are using Redsync in a project please send a pull request to add it to the list.

vearne/redsync