waitingcache

README

Waiting cache

A waiting cache is used at the destination of a migration. When you create NewWaitingCache it returns a local and a remote storage.StorageProvider.

• Any reads from the local result in a NeedAt being sent. It will then WAIT until all the data is available.
• Any writes to the remote result in the data being marked as locally available, and will unblock any reads waiting.
• Any writes to the local result in a DontNeedAt being sent, and the block is marked as locally available.
• Reads from remote are unsupported.

It should be noted that only COMPLETE blocks are tracked. For this reason remote WriteAts should be aligned and complete blocks - as from a migrator.

Documentation

Index

• func NewWaitingCache(prov storage.Provider, blockSize int) (*Local, *Remote)
• func NewWaitingCacheWithLogger(prov storage.Provider, blockSize int, log types.Logger) (*Local, *Remote)
• type Local
  • func (wcl *Local) Availability() (int, int)
  • func (wcl *Local) CancelWrites(offset int64, length int64)
  • func (wcl *Local) Close() error
  • func (wcl *Local) DirtyBlocks(blocks []uint)
  • func (wcl *Local) Flush() error
  • func (wcl *Local) GetMetrics() *Metrics
  • func (wcl *Local) ReadAt(buffer []byte, offset int64) (int, error)
  • func (wcl *Local) SendSiloEvent(eventType storage.EventType, eventData storage.EventData) []storage.EventReturnData
  • func (wcl *Local) Size() uint64
  • func (wcl *Local) WriteAt(buffer []byte, offset int64) (int, error)
• type Metrics
• type Remote
  • func (wcr *Remote) CancelWrites(offset int64, length int64)
  • func (wcr *Remote) Close() error
  • func (wcr *Remote) Flush() error
  • func (wcr *Remote) GetMetrics() *Metrics
  • func (wcr *Remote) ReadAt(_ []byte, _ int64) (int, error)
  • func (wcr *Remote) SendSiloEvent(eventType storage.EventType, eventData storage.EventData) []storage.EventReturnData
  • func (wcr *Remote) Size() uint64
  • func (wcr *Remote) WriteAt(buffer []byte, offset int64) (int, error)
• type WaitingCache
  • func (i *WaitingCache) GetMetrics() *Metrics

Functions

func NewWaitingCache

func NewWaitingCache(prov storage.Provider, blockSize int) (*Local, *Remote)

func NewWaitingCacheWithLogger

func NewWaitingCacheWithLogger(prov storage.Provider, blockSize int, log types.Logger) (*Local, *Remote)

Types

type Local

type Local struct {
	storage.ProviderWithEvents

	NeedAt     func(offset int64, length int32)
	DontNeedAt func(offset int64, length int32)
	// contains filtered or unexported fields
}

func (*Local) Availability

func (wcl *Local) Availability() (int, int)

func (*Local) CancelWrites

func (wcl *Local) CancelWrites(offset int64, length int64)

func (*Local) Close

func (wcl *Local) Close() error

func (*Local) DirtyBlocks

func (wcl *Local) DirtyBlocks(blocks []uint)

func (*Local) Flush

func (wcl *Local) Flush() error

func (*Local) GetMetrics

func (wcl *Local) GetMetrics() *Metrics

func (*Local) ReadAt

func (wcl *Local) ReadAt(buffer []byte, offset int64) (int, error)

func (*Local) SendSiloEvent

func (wcl *Local) SendSiloEvent(eventType storage.EventType, eventData storage.EventData) []storage.EventReturnData

Relay events to embedded StorageProvider

func (*Local) Size

func (wcl *Local) Size() uint64

func (*Local) WriteAt

func (wcl *Local) WriteAt(buffer []byte, offset int64) (int, error)

type Metrics

type Metrics struct {
	WaitForBlock             uint64
	WaitForBlockHadRemote    uint64
	WaitForBlockHadLocal     uint64
	WaitForBlockTime         time.Duration
	WaitForBlockLock         uint64
	WaitForBlockLockDone     uint64
	MarkAvailableLocalBlock  uint64
	MarkAvailableRemoteBlock uint64
	AvailableLocal           uint64
	AvailableRemote          uint64
}

type Remote

type Remote struct {
	storage.ProviderWithEvents
	// contains filtered or unexported fields
}

func (*Remote) CancelWrites

func (wcr *Remote) CancelWrites(offset int64, length int64)

func (*Remote) Close

func (wcr *Remote) Close() error

func (*Remote) Flush

func (wcr *Remote) Flush() error

func (*Remote) GetMetrics

func (wcr *Remote) GetMetrics() *Metrics

func (*Remote) ReadAt

func (wcr *Remote) ReadAt(_ []byte, _ int64) (int, error)

func (*Remote) SendSiloEvent

func (wcr *Remote) SendSiloEvent(eventType storage.EventType, eventData storage.EventData) []storage.EventReturnData

Relay events to embedded StorageProvider

func (*Remote) Size

func (wcr *Remote) Size() uint64

func (*Remote) WriteAt

func (wcr *Remote) WriteAt(buffer []byte, offset int64) (int, error)

type WaitingCache

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

*

• Waiting cache StorageProvider *
• NB: This tracks COMPLETE blocks only. Not partial ones. *

func (*WaitingCache) GetMetrics

func (i *WaitingCache) GetMetrics() *Metrics