storage

Documentation

Index

• Variables
• type Batcher
• type BloomFilter
• type Cacher
• type EpochStartNotifier
• type PathManagerHandler
• type Persister
• type Storer

Variables

var ErrClosingPersisters = errors.New("cannot close all the persisters")

ErrClosingPersisters signals that not all persisters were closed

var ErrDestroyingUnit = errors.New("destroy unit didn't remove all the persisters")

ErrDestroyingUnit signals that the destroy unit method did not manage to destroy all the persisters in a pruning storer

var ErrDuplicateKeyToAdd = errors.New("the key can not be added as it already exists")

ErrDuplicateKeyToAdd signals that a key can not be added as it already exists

var ErrEmptyKey = errors.New("key is empty")

ErrEmptyKey is raised when a key is empty

var ErrEmptyPruningPathTemplate = errors.New("empty path template for pruning storers")

ErrEmptyPruningPathTemplate signals that an empty path template for pruning storers has been provided

var ErrEmptyStaticPathTemplate = errors.New("empty path template for static storers")

ErrEmptyStaticPathTemplate signals that an empty path template for static storers has been provided

var ErrInvalidBatch = errors.New("batch is invalid")

ErrInvalidBatch is raised when the used batch is invalid

var ErrInvalidNumOpenFiles = errors.New("maxOpenFiles is invalid")

ErrInvalidNumOpenFiles is raised when the max num of open files is less than 1

var ErrInvalidNumberOfActivePersisters = errors.New("invalid number of active persisters")

ErrInvalidNumberOfActivePersisters signals that an invalid number of active persisters has been provided

var ErrInvalidNumberOfEpochsToSave = errors.New("invalid number of epochs to save")

ErrInvalidNumberOfEpochsToSave signals that an invalid number of epochs to save has been provided

var ErrInvalidNumberOfPersisters = errors.New("invalid number of active persisters")

ErrInvalidNumberOfPersisters signals that an invalid number of persisters has been provided

var ErrInvalidPruningPathTemplate = errors.New("invalid path template for pruning storers")

ErrInvalidPruningPathTemplate signals that an invalid path template for pruning storers has been provided

var ErrInvalidStaticPathTemplate = errors.New("invalid path template for static storers")

ErrInvalidStaticPathTemplate signals that an invalid path template for static storers has been provided

var ErrKeyNotFound = errors.New("key not found")

ErrKeyNotFound is raised when a key is not found

var ErrNilBloomFilter = errors.New("expected not nil bloom filter")

ErrNilBloomFilter is raised when a nil bloom filter is provided

var ErrNilCacher = errors.New("expected not nil cacher")

ErrNilCacher is raised when a nil cacher is provided

var ErrNilConfig = errors.New("nil config")

ErrNilConfig signals that a nil configuration has been received

var ErrNilEpochStartNotifier = errors.New("nil epoch start notifier")

ErrNilEpochStartNotifier signals that a nil epoch start notifier has been provided

var ErrNilPathManager = errors.New("nil path manager")

ErrNilPathManager signals that a nil path manager has been provided

var ErrNilPersister = errors.New("expected not nil persister")

ErrNilPersister is raised when a nil persister is provided

var ErrNilPersisterFactory = errors.New("nil persister factory")

ErrNilPersisterFactory signals that a nil persister factory has been provided

var ErrNilShardCoordinator = errors.New("nil shard coordinator")

ErrNilShardCoordinator signals that a nil shard coordinator has been provided

var ErrNotSupportedCacheType = errors.New("not supported cache type")

ErrNotSupportedCacheType is raised when an unsupported cache type is provided

var ErrNotSupportedDBType = errors.New("nit supported db type")

ErrNotSupportedDBType is raised when an unsupported database type is provided

var ErrNotSupportedHashType = errors.New("hash type not supported")

ErrNotSupportedHashType is raised when an unsupported hasher is provided

var ErrSerialDBIsClosed = errors.New("serialDB is closed")

ErrSerialDBIsClosed is raised when the serialDB is closed

Types

type Batcher

type Batcher interface {
	// Put inserts one entry - key, value pair - into the batch
	Put(key []byte, val []byte) error
	// Delete deletes the batch
	Delete(key []byte) error
	// Reset clears the contents of the batch
	Reset()
	// IsInterfaceNil returns true if there is no value under the interface
	IsInterfaceNil() bool
}

Batcher allows to batch the data first then write the batch to the persister in one go

type BloomFilter

type BloomFilter interface {
	//Add adds the value to the bloom filter
	Add([]byte)
	// MayContain checks if the value is in in the set. If it returns 'false',
	//the item is definitely not in the DB
	MayContain([]byte) bool
	//Clear sets all the bits from the filter to 0
	Clear()
	// IsInterfaceNil returns true if there is no value under the interface
	IsInterfaceNil() bool
}

BloomFilter provides services for filtering database requests

type Cacher

type Cacher interface {
	// Clear is used to completely clear the cache.
	Clear()
	// Put adds a value to the cache.  Returns true if an eviction occurred.
	Put(key []byte, value interface{}) (evicted bool)
	// Get looks up a key's value from the cache.
	Get(key []byte) (value interface{}, ok bool)
	// Has checks if a key is in the cache, without updating the
	// recent-ness or deleting it for being stale.
	Has(key []byte) bool
	// Peek returns the key value (or undefined if not found) without updating
	// the "recently used"-ness of the key.
	Peek(key []byte) (value interface{}, ok bool)
	// HasOrAdd checks if a key is in the cache  without updating the
	// recent-ness or deleting it for being stale,  and if not adds the value.
	// Returns whether found and whether an eviction occurred.
	HasOrAdd(key []byte, value interface{}) (ok, evicted bool)
	// Remove removes the provided key from the cache.
	Remove(key []byte)
	// RemoveOldest removes the oldest item from the cache.
	RemoveOldest()
	// Keys returns a slice of the keys in the cache, from oldest to newest.
	Keys() [][]byte
	// Len returns the number of items in the cache.
	Len() int
	// MaxSize returns the maximum number of items which can be stored in the cache.
	MaxSize() int
	// RegisterHandler registers a new handler to be called when a new data is added
	RegisterHandler(func(key []byte))
	// IsInterfaceNil returns true if there is no value under the interface
	IsInterfaceNil() bool
}

Cacher provides caching services

type EpochStartNotifier

type EpochStartNotifier interface {
	RegisterHandler(handler notifier.SubscribeFunctionHandler)
	UnregisterHandler(handler notifier.SubscribeFunctionHandler)
	NotifyAll(hdr data.HeaderHandler)
	IsInterfaceNil() bool
}

EpochStartNotifier defines which actions should be done for handling new epoch's events

type PathManagerHandler

type PathManagerHandler interface {
	PathForEpoch(shardId string, epoch uint32, identifier string) string
	PathForStatic(shardId string, identifier string) string
	IsInterfaceNil() bool
}

PathManagerHandler defines which actions should be done for generating paths for databases directories

type Persister

type Persister interface {
	// Put add the value to the (key, val) persistence medium
	Put(key, val []byte) error
	// Get gets the value associated to the key
	Get(key []byte) ([]byte, error)
	// Has returns true if the given key is present in the persistence medium
	Has(key []byte) error
	// Init initializes the persistence medium and prepares it for usage
	Init() error
	// Close closes the files/resources associated to the persistence medium
	Close() error
	// Remove removes the data associated to the given key
	Remove(key []byte) error
	// Destroy removes the persistence medium stored data
	Destroy() error
	// DestroyClosed removes the already closed persistence medium stored data
	DestroyClosed() error
	// IsInterfaceNil returns true if there is no value under the interface
	IsInterfaceNil() bool
}

Persister provides storage of data services in a database like construct

type Storer

type Storer interface {
	Put(key, data []byte) error
	Get(key []byte) ([]byte, error)
	GetFromEpoch(key []byte, epoch uint32) ([]byte, error)
	Has(key []byte) error
	HasInEpoch(key []byte, epoch uint32) error
	SearchFirst(key []byte) ([]byte, error)
	Remove(key []byte) error
	ClearCache()
	DestroyUnit() error
	IsInterfaceNil() bool
	Close() error
}

Storer provides storage services in a two layered storage construct, where the first layer is represented by a cache and second layer by a persitent storage (DB-like)