README.md

Distributed Mutex on Azure Lease Blobs

This package implements distributed lock available for multiple processes. Possible use-cases include exclusive access to shared data, leader election, etc.

Azure Storage supports the feature that guarantees exclusive access to the blobs using basic lease functionality: it's possible to acquire a fixed or infinite duration lease, renew and then release it. Thus it's possible to implement a basic distributed mutex on top of blobs.

Basic Abstractions

AzureMutex

A wrapper on top of Azure blobs API encapsulates API interactions and provides three primary functions: Acquire, Renew, Release.

Locker

Top-level abstractions that support background renewal of the acquired lease.

Locker Usage

Installation

go get -u github.com/youscan/go-azuremutex

Configuration

var options = azmutex.MutexOptions{
	AccountName:   "mystorageaccount",
	AccountKey:    "******",
	ContainerName: "locks",
}

Use Locker with automated renewal

locker := azmutex.NewLocker(options, "migration")

err = locker.Lock()
...
// As soon the lease was acquired we can safely do exclusive job
RunDatabaseMigration()
...
err = locker.Unlock()

Use AzureMutex with lease that will expire in 60 seconds

mutex := azmutex.NewMutex(options)

err = mutex.Acquire("migration", 60)
...
// This code is only safely to run within 60 seconds window
RunDatabaseMigration()
...
err = mutex.Release("migration")

Reference

• Azure / Architecture / Cloud Design Patterns / Leader Election pattern
• Microsoft Azure Development Cookbook Second Edition: Leasing a blob and implementing distributed locks