lock

Documentation

Index

• Constants
• Variables
• type ErrorLocker
  • func LongOperation(db prefixer.Prefixer, name string) ErrorLocker
• type ErrorRWLocker
  • func 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 maximum time to wait before returning control to caller.
	WaitTimeout = 1 * time.Minute

	// WaitRetry 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)

func LongOperation

func 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.

type ErrorRWLocker

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

ErrorRWLocker is the interface for a RWLock as inspired by RWMutex

func ReadWrite

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

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).