lock

Documentation

Index

• Constants
• Variables
• type ErrorLocker
• type ErrorRWLocker
• type Getter
  • func New(client redis.UniversalClient) Getter
• type InMemoryLockGetter
  • func NewInMemory() *InMemoryLockGetter
  • func (i *InMemoryLockGetter) LongOperation(db prefixer.Prefixer, name string) ErrorLocker
  • func (i *InMemoryLockGetter) ReadWrite(_ prefixer.Prefixer, name string) ErrorRWLocker
• type RedisLockGetter
  • func NewRedisLockGetter(client redis.UniversalClient) *RedisLockGetter
  • func (r *RedisLockGetter) LongOperation(db prefixer.Prefixer, name string) ErrorLocker
  • func (r *RedisLockGetter) ReadWrite(db prefixer.Prefixer, name string) ErrorRWLocker

Constants

const (

	// LockTimeout is the expiration of a redis lock if any operation is longer
	// than this, it should refresh the lock.
	LockTimeout = 20 * time.Second

	// WaitTimeout is the maximum time to wait before returning control to caller.
	WaitTimeout = 1 * time.Minute

	// WaitRetry is the time to wait between retries.
	WaitRetry = 100 * time.Millisecond
)

Variables

var (
	// ErrTooManyRetries is the error returned when despite several tries
	// we never managed to get a lock
	ErrTooManyRetries = errors.New("abort after too many failures without getting the lock")
)

Types

type ErrorLocker

type ErrorLocker interface {
	Lock() error
	Unlock()
}

An ErrorLocker is a locker which can fail (returns an error)

type ErrorRWLocker

type ErrorRWLocker interface {
	ErrorLocker
	RLock() error
	RUnlock()
}

ErrorRWLocker is the interface for a RWLock as inspired by RWMutex

type Getter

type Getter interface {
	// ReadWrite returns the read/write lock for the given name.
	// By convention, the name should be prefixed by the instance domain on which
	// it applies, then a slash and the package name (ie alice.example.net/vfs).
	ReadWrite(db prefixer.Prefixer, name string) ErrorRWLocker

	// LongOperation returns a lock suitable for long operations. It will refresh
	// the lock in redis to avoid its automatic expiration.
	LongOperation(db prefixer.Prefixer, name string) ErrorLocker
}

Getter returns a lock on a resource matching the given `name`.

func New

func New(client redis.UniversalClient) Getter

type InMemoryLockGetter

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

func NewInMemory

func NewInMemory() *InMemoryLockGetter

func (*InMemoryLockGetter) LongOperation

func (i *InMemoryLockGetter) LongOperation(db prefixer.Prefixer, name string) ErrorLocker

LongOperation returns a lock suitable for long operations. It will refresh the lock in redis to avoid its automatic expiration.

func (*InMemoryLockGetter) ReadWrite

func (i *InMemoryLockGetter) ReadWrite(_ prefixer.Prefixer, name string) ErrorRWLocker

type RedisLockGetter

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

func NewRedisLockGetter

func NewRedisLockGetter(client redis.UniversalClient) *RedisLockGetter

func (*RedisLockGetter) LongOperation

func (r *RedisLockGetter) LongOperation(db prefixer.Prefixer, name string) ErrorLocker

LongOperation returns a lock suitable for long operations. It will refresh the lock in redis to avoid its automatic expiration.

func (*RedisLockGetter) ReadWrite

func (r *RedisLockGetter) ReadWrite(db prefixer.Prefixer, name string) ErrorRWLocker