redsync

README

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 gopkg.in/redsync.v1

The only dependencies are the Go distribution and Redigo.

Documentation

• Reference

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.

Documentation

Overview

Package redsync provides a Redis-based distributed mutual exclusion lock implementation as described in the post http://redis.io/topics/distlock.

Values containing the types defined in this package should not be copied.

Index

• Variables
• type Mutex
  • func NewMutex(ctx context.Context, name string, options ...Option) *Mutex
  • func (m *Mutex) Extend() bool
  • func (m *Mutex) GetToken() string
  • func (m *Mutex) Lock() error
  • func (m *Mutex) Unlock() bool
• type Option
  • func SetDriftFactor(factor float64) Option
  • func SetExpiry(expiry time.Duration) Option
  • func SetRetryDelay(delayMin, delayMax time.Duration) Option
  • func SetToken(token string) Option
  • func SetTries(tries int) Option
• type OptionFunc
  • func (f OptionFunc) Apply(mutex *Mutex)
• type Pool
• type Redsync
  • func New(pools []Pool) *Redsync
  • func (r *Redsync) NewMutex(ctx context.Context, name string, options ...Option) *Mutex

Variables

var ErrFailed = errors.New("redsync: failed to acquire lock")

ErrFailed indicates error happened when acquire the lock

Types

type Mutex

type Mutex struct {
	// contains filtered or unexported fields
}

Mutex is a distributed mutual exclusion lock.

func NewMutex

func NewMutex(ctx context.Context, name string, options ...Option) *Mutex

NewMutex create a mutex using default redsync

func (*Mutex) Extend

func (m *Mutex) Extend() bool

Extend resets the mutex's expiry and returns the status of expiry extension. It is a run-time error if m is not locked on entry to Extend.

func (*Mutex) GetToken

func (m *Mutex) GetToken() string

GetToken return the token id for the mutex

func (*Mutex) Lock

func (m *Mutex) Lock() error

Lock locks m. In case it returns an error on failure, you may retry to acquire the lock by calling this method again.

func (*Mutex) Unlock

func (m *Mutex) Unlock() bool

Unlock unlocks m and returns the status of unlock. It is a run-time error if m is not locked on entry to Unlock.

type Option

type Option interface {
	Apply(*Mutex)
}

An Option configures a mutex.

func SetDriftFactor

func SetDriftFactor(factor float64) Option

SetDriftFactor can be used to set the clock drift factor.

func SetExpiry

func SetExpiry(expiry time.Duration) Option

SetExpiry can be used to set the expiry of a mutex to the given value.

func SetRetryDelay

func SetRetryDelay(delayMin, delayMax time.Duration) Option

SetRetryDelay can be used to set the amount of time to wait between retries.

func SetToken

func SetToken(token string) Option

SetToken set the mutex token

func SetTries

func SetTries(tries int) Option

SetTries can be used to set the number of times lock acquire is attempted.

type OptionFunc

type OptionFunc func(*Mutex)

OptionFunc is a function that configures a mutex.

func (OptionFunc) Apply

func (f OptionFunc) Apply(mutex *Mutex)

Apply calls f(mutex)

type Pool

type Pool interface {
	Get() redis.Cmdable
}

Pool maintains a pool of Redis connections.

type Redsync

type Redsync struct {
	// contains filtered or unexported fields
}

Redsync provides a simple method for creating distributed mutexes using multiple Redis connection pools.

func New

func New(pools []Pool) *Redsync

New creates and returns a new Redsync instance from given Redis connection pools.

func (*Redsync) NewMutex

func (r *Redsync) NewMutex(ctx context.Context, name string, options ...Option) *Mutex

NewMutex returns a new distributed mutex with given name.