lock

Documentation

Index

• Variables
• type FuncMockLock
  • func (ml FuncMockLock) Unlock() error
• type FuncMockLocker
  • func (ml FuncMockLocker) Lock(key string, options ...Option) (RuleLock, error)
• type GetSession
• type MockLocker
  • func (tlkr *MockLocker) Lock(key string, options ...Option) (RuleLock, error)
• type Option
  • func MethodForLock(method string) Option
  • func PatternForLock(pattern string) Option
• type RuleLock
• type RuleLocker
  • func NewCoolOffLocker(expiration time.Duration) RuleLocker
  • func NewMapLocker() RuleLocker
  • func NewNestedLocker(outer, inner RuleLocker) RuleLocker
  • func NewSessionLocker(getSession GetSession, lockTimeout int, closeSession, useTryLock bool) RuleLocker
  • func NewV3Locker(cl *v3.Client, lockTimeout int, useTryLock bool) RuleLocker
  • func WithMetrics(ruleLocker RuleLocker, name string) RuleLocker

Variables

var ErrLockedLocally = errors.New("locked locally")

ErrLockedLocally indicates that a local goroutine holds the lock and no attempt will be made to obtain the lock via etcd.

var ErrNilMutex = errors.New("mutex is nil")

ErrNilMutex indicates that the lock has a nil mutex

Types

type FuncMockLock

type FuncMockLock struct {
	UnlockF func() error
}

FuncMockLock instances are driven by functions that are provided.

func (FuncMockLock) Unlock

func (ml FuncMockLock) Unlock() error

Unlock is a mock implementation of RuleLock.Unlock

type FuncMockLocker

type FuncMockLocker struct {
	LockF func(string, ...Option) (RuleLock, error)
}

FuncMockLocker instances are driven by functions that are provided.

func (FuncMockLocker) Lock

func (ml FuncMockLocker) Lock(key string, options ...Option) (RuleLock, error)

Lock is a mock implementation of RuleLock.Lock

type GetSession

type GetSession func(context.Context) (*v3c.Session, error)

type MockLocker

type MockLocker struct {
	Channel  chan bool
	ErrorMsg *string
}

MockLocker implements the RuleLocker interface.

func (*MockLocker) Lock

func (tlkr *MockLocker) Lock(key string, options ...Option) (RuleLock, error)

type Option

type Option func(lo *options)

Option instances are used to provide optional arguments to the RuleLock.Lock method.

func MethodForLock

func MethodForLock(method string) Option

MethodForLock is used to specify the context in which the lock was obtained.

func PatternForLock

func PatternForLock(pattern string) Option

PatternForLock is used to specify the pattern that was used to build the lock key for metric tracking purposes.

type RuleLock

type RuleLock interface {
	Unlock() error
}

type RuleLocker

type RuleLocker interface {
	Lock(string, ...Option) (RuleLock, error)
}

func NewCoolOffLocker

func NewCoolOffLocker(expiration time.Duration) RuleLocker

NewCoolOffLocker creates a simple locker that will prevent a lock from being obtained if a previous attempt (successful or not) was made within the specified expiration period. It is intended to be used with other lockers to prevent excessive locking using more expensive resources (e.g. etcd). It is theoretically possible for two callers to obtain the same lock, if the cooloff period expires before the first caller releases the lock; therefore this locker needs to be used with a nested locker to prevent two callers from accessing the same protected resource.

func NewMapLocker

func NewMapLocker() RuleLocker

func NewNestedLocker

func NewNestedLocker(outer, inner RuleLocker) RuleLocker

NewNestedLocker creates a locker that protects the inner locker with an outer locker, so that no unnecessary calls are made to the inner locker when attempting to obtain an unavailable lock.

func NewSessionLocker

func NewSessionLocker(getSession GetSession, lockTimeout int, closeSession, useTryLock bool) RuleLocker

NewSessionLocker creates a new locker with the provided session constructor. Note that if closeSession is false, it means that the session provided by getSession will not be closed but instead be reused. In that case the locker must be protected by another locker (for instance an in-memory locker) because locks within the same session are reentrant which means that two goroutines can obtain the same lock.

func NewV3Locker

func NewV3Locker(cl *v3.Client, lockTimeout int, useTryLock bool) RuleLocker

NewV3Locker creates a locker backed by etcd V3.

func WithMetrics

func WithMetrics(ruleLocker RuleLocker, name string) RuleLocker

WithMetrics decorates a locker with metrics.