database

Documentation

Overview

Package database provides KV database for meta-information

Index

• Variables
• type Batch
• type PrefixReader
• type Reader
• type ReaderWriter
• type Storage
• type StorageProcessor
• type Transaction
• type Writer

Variables

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

Errors for Storage

Types

type Batch

type Batch interface {
	Writer

	// Write closes batch and send accumulated writes to the database
	Write() error
}

Batch provides a way to pack many writes.

type PrefixReader

type PrefixReader interface {
	HasPrefix(prefix []byte) bool
	ProcessByPrefix(prefix []byte, proc StorageProcessor) error
	KeysByPrefix(prefix []byte) [][]byte
	FetchByPrefix(prefix []byte) [][]byte
}

PrefixReader provides prefixed operations

type Reader

type Reader interface {
	Get(key []byte) ([]byte, error)
}

Reader provides KV read calls

type ReaderWriter

type ReaderWriter interface {
	Reader
	Writer
}

ReaderWriter combines Reader and Writer

type Storage

type Storage interface {
	Reader
	Writer

	PrefixReader

	CreateBatch() Batch
	OpenTransaction() (Transaction, error)

	CreateTemporary() (Storage, error)

	Open() error
	Close() error
	CompactDB() error
	Drop() error
}

Storage is an interface to KV storage

type StorageProcessor

type StorageProcessor func(key []byte, value []byte) error

StorageProcessor is a function to process one single storage entry

type Transaction

type Transaction interface {
	Reader
	Writer

	Commit() error
	Discard()
}

Transaction provides isolated atomic way to perform updates.

Transactions might be expensive. Transaction should always finish with either Discard() or Commit()

type Writer

type Writer interface {
	Put(key []byte, value []byte) error
	Delete(key []byte) error
}

Writer provides KV update/delete calls