persistence

Documentation

Overview

Package persistence adds a layer which handles data storage. This package separates the data from the business layer and is responsible for saving and retrieving it.

Index

• Constants
• func CheckStoragePermission(dirBasePath string) error
• func EnsureDirectoryExists(dirBasePath, newDirName string) error
• func Read(filePath string) ([]byte, error)
• func Write(filePath string, data []byte) error
• type DataDescriptor
• type Handle
  • func NewDiskHandle(path string) (Handle, error)
  • func NewEncryptedPersistence(handle Handle, password string) Handle

Constants

const KeyLength = encryption.KeyLength

KeyLength represents the byte size of the key.

Functions

func CheckStoragePermission

func CheckStoragePermission(dirBasePath string) error

CheckStoragePermission returns an error if we don't have both read and write access to a directory.

func EnsureDirectoryExists

func EnsureDirectoryExists(dirBasePath, newDirName string) error

EnsureDirectoryExists creates a new directory in a base path if it doesn't exist, returns nil if it does, and errors out if the base path doesn't exist.

func Read

func Read(filePath string) ([]byte, error)

Read a file from a file system

func Write

func Write(filePath string, data []byte) error

Write creates and writes data to a file

Types

type DataDescriptor

type DataDescriptor interface {
	Name() string
	Directory() string
	Content() ([]byte, error)
}

DataDescriptor is an interface representing data saved in the persistence layer represented by Handle.

type Handle

type Handle interface {

	// Save takes the provided data and persists it under the given name in the
	// provided directory appropriate for the given persistent storage
	// implementation.
	Save(data []byte, directory string, name string) error

	// Snapshot takes the provided data and persists it as an unique snapshot
	// file in the provided directory appropriate for the given persistent
	// storage implementation.
	Snapshot(data []byte, directory string, name string) error

	// ReadAll returns all non-archived data. It returns two channels: the first
	// channel returned is a non-buffered channel streaming DataDescriptors of
	// all data read. The second channel is a non-buffered channel streaming all
	// errors occurred during reading. Returned channels can be integrated
	// in a pipeline pattern. The function is non-blocking. Channels are closed
	// when there is no more to be read.
	ReadAll() (<-chan DataDescriptor, <-chan error)

	// Archive marks the entire directory with the name provided as archived
	// so that the data in that directory is not returned from ReadAll.
	Archive(directory string) error
}

Handle is an interface for data persistence. Underlying implementation can write data e.g. to disk, cache, or hardware module.

func NewDiskHandle

func NewDiskHandle(path string) (Handle, error)

NewDiskHandle creates on-disk data persistence handle

func NewEncryptedPersistence

func NewEncryptedPersistence(handle Handle, password string) Handle

NewEncryptedPersistence creates an adapter for the disk persistence to store data in an encrypted format