newstorage

Documentation

Index

• Variables
• type Iterator
• type MultiError
• type Operation
• type Provider
• type QueryOption
  • func WithPageSize(size int) QueryOption
• type QueryOptions
• type Store
• type StoreConfiguration
• type Tag

Variables

var ErrDataNotFound = errors.New("data not found")

ErrDataNotFound is returned when data is not found.

var ErrStoreNotFound = errors.New("store not found")

ErrStoreNotFound is returned when a store is not found.

Types

type Iterator

type Iterator interface {
	// Next moves the pointer to the next entry in the iterator. It returns false if the iterator is exhausted.
	Next() (bool, error)

	// Key returns the key of the current entry.
	Key() (string, error)

	// Value returns the value of the current entry.
	Value() ([]byte, error)

	// Tags returns the tags associated with the key of the current entry.
	Tags() ([]Tag, error)

	// Close closes this iterator object, freeing resources.
	Close() error
}

Iterator allows for iteration over a collection of entries in a store.

type MultiError

type MultiError interface {
	error
	Errors() []error // Errors returns the error objects for all operations.
}

MultiError represents the errors that occurred during a bulk operation.

type Operation

type Operation struct {
	Key   string
	Value []byte // A nil value will result in a delete operation.
	Tags  []Tag  // Optional.
}

Operation represents an operation to be performed in the Batch method.

type Provider

type Provider interface {
	// OpenStore opens a store with the given name and returns a handle.
	// If the store has never been opened before, then it is created.
	// Store names are not case-sensitive. If name is blank, then an error will be returned.
	OpenStore(name string) (Store, error)

	// SetStoreConfig sets the configuration on a store.
	// The store must be created prior to calling this method.
	// If the store cannot be found, then an error wrapping ErrStoreNotFound will be returned.
	// If name is blank, then an error will be returned.
	SetStoreConfig(name string, config StoreConfiguration) error

	// GetStoreConfig gets the current store configuration.
	// The store must be created prior to calling this method.
	// If the store cannot be found, then an error wrapping ErrStoreNotFound will be returned.
	// If name is blank, then an error will be returned.
	GetStoreConfig(name string) (StoreConfiguration, error)

	// GetOpenStores returns all currently open stores.
	GetOpenStores() []Store

	// Close closes all stores created under this store provider.
	// For persistent store implementations, this does not delete any data in the stores.
	Close() error
}

Provider represents a storage provider.

type QueryOption

type QueryOption func(opts *QueryOptions)

QueryOption represents an option for a Query call in a store.

func WithPageSize

func WithPageSize(size int) QueryOption

WithPageSize sets the maximum page size for data retrievals done within the Iterator returned by the Query call. Paging is handled internally by the Iterator. Higher values may reduce CPU time and the number of database calls at the expense of higher memory usage.

type QueryOptions

type QueryOptions struct {
	// PageSize sets the page size used by the Store.Query method.
	PageSize int
}

QueryOptions represents various options for Query calls in a store.

type Store

type Store interface {
	// Put stores the key + value pair along with the (optional) tags.
	// If key is empty or value is nil, then an error will be returned.
	Put(key string, value []byte, tags ...Tag) error

	// Get fetches the value associated with the given key.
	// If key cannot be found, then an error wrapping ErrDataNotFound will be returned.
	// If key is empty, then an error will be returned.
	Get(key string) ([]byte, error)

	// Get fetches all tags associated with the given key.
	// If key cannot be found, then an error wrapping ErrDataNotFound will be returned.
	// If key is empty, then an error will be returned.
	GetTags(key string) ([]Tag, error)

	// GetBulk fetches the values associated with the given keys.
	// If no data exists under a given key, then a nil []byte is returned for that value. It is not considered an error.
	// Depending on the implementation, this method may be faster than calling Get for each key individually.
	// If any of the given keys are empty, then an error will be returned.
	GetBulk(keys ...string) ([][]byte, error)

	// Query returns all data that satisfies the expression. Expression format: TagName:TagValue.
	// If TagValue is not provided, then all data associated with the TagName will be returned.
	// For now, expression can only be a single tag Name + Value pair.
	// If no options are provided, then defaults will be used.
	Query(expression string, options ...QueryOption) (Iterator, error)

	// Delete deletes the key + value pair (and all tags) associated with key.
	// If key is empty, then an error will be returned.
	Delete(key string) error

	// Batch performs multiple Put and/or Delete operations in order.
	// Depending on the implementation, this method may be faster than repeated Put and/or Delete calls.
	// If any of the given keys are empty, then an error will be returned.
	Batch(operations []Operation) error

	// Flush forces any queued up Put and/or Delete operations to execute.
	// If the Store implementation doesn't queue up operations, then this method is a no-op.
	Flush() error

	// Close closes this store object, freeing resources. For persistent store implementations, this does not delete
	// any data in the underlying databases.
	Close() error
}

Store represents a storage database.

type StoreConfiguration

type StoreConfiguration struct {
	TagNames []string // A list of Tag names that key + value pairs in this store can be associated with.
}

StoreConfiguration represents the configuration of a store.

type Tag

type Tag struct {
	// Name can be used to tag a given key + value pair as belonging to a group.
	// Tag Names are static values that the store must be configured with (see TagNames in StoreConfiguration).
	Name string
	// Value can be used to indicate some optional metadata associated with a given key + value pair + tag name.
	// Unlike Tag Names, Tag Values are dynamic and are not specified during store creation.
	Value string
}

Tag represents a Name + Value pair that can be associated with a key + value pair for querying later.