object

Documentation

Overview

Package object implements repository support for content-addressable objects of arbitrary size.

Index

• Constants
• Variables
• type Format
• type HasObjectID
• type ID
  • func DirectObjectID(blockID string) ID
  • func IndirectObjectID(indexObjectID ID) ID
  • func ParseID(s string) (ID, error)
  • func (i ID) BlockID() (string, bool)
  • func (i ID) IndexObjectID() (ID, bool)
  • func (i ID) String() string
  • func (i ID) Validate() error
• type Manager
  • func NewObjectManager(ctx context.Context, bm blockManager, f Format, opts ManagerOptions) (*Manager, error)
  • func (om *Manager) NewWriter(ctx context.Context, opt WriterOptions) Writer
  • func (om *Manager) Open(ctx context.Context, objectID ID) (Reader, error)
  • func (om *Manager) VerifyObject(ctx context.Context, oid ID) (int64, []string, error)
• type ManagerOptions
• type Reader
• type Writer
• type WriterOptions

Constants

const DefaultSplitter = "DYNAMIC"

DefaultSplitter is the name of the splitter used by default for new repositories.

Variables

var SupportedSplitters []string

SupportedSplitters is a list of supported object splitters including:

NEVER    - prevents objects from ever splitting
FIXED    - always splits large objects exactly at the maximum block size boundary
DYNAMIC  - dynamically splits large objects based on rolling hash of contents.

Types

type Format

type Format struct {
	Splitter     string `json:"splitter,omitempty"`     // splitter used to break objects into storage blocks
	MinBlockSize int    `json:"minBlockSize,omitempty"` // minimum block size used with dynamic splitter
	AvgBlockSize int    `json:"avgBlockSize,omitempty"` // approximate size of storage block (used with dynamic splitter)
	MaxBlockSize int    `json:"maxBlockSize,omitempty"` // maximum size of storage block
}

Format describes the format of objects in a repository.

type HasObjectID

type HasObjectID interface {
	ObjectID() ID
}

HasObjectID exposes the identifier of an object.

type ID

type ID string

ID is an identifier of a repository object. Repository objects can be stored.

1. In a single content block, this is the most common case for small objects.
2. In a series of content blocks with an indirect block pointing at them (multiple indirections are allowed). This is used for larger files. Object IDs using indirect blocks start with "I"

func DirectObjectID

func DirectObjectID(blockID string) ID

DirectObjectID returns direct object ID based on the provided block ID.

func IndirectObjectID

func IndirectObjectID(indexObjectID ID) ID

IndirectObjectID returns indirect object ID based on the underlying index object ID.

func ParseID

func ParseID(s string) (ID, error)

ParseID converts the specified string into object ID

func (ID) BlockID

func (i ID) BlockID() (string, bool)

BlockID returns the block ID of the underlying content storage block.

func (ID) IndexObjectID

func (i ID) IndexObjectID() (ID, bool)

IndexObjectID returns the object ID of the underlying index object.

func (ID) String

func (i ID) String() string

String returns string representation of ObjectID that is suitable for displaying in the UI.

func (ID) Validate

func (i ID) Validate() error

Validate checks the ID format for validity and reports any errors.

type Manager

type Manager struct {
	Format Format
	// contains filtered or unexported fields
}

Manager implements a content-addressable storage on top of blob storage.

func NewObjectManager

func NewObjectManager(ctx context.Context, bm blockManager, f Format, opts ManagerOptions) (*Manager, error)

NewObjectManager creates an ObjectManager with the specified block manager and format.

func (*Manager) NewWriter

func (om *Manager) NewWriter(ctx context.Context, opt WriterOptions) Writer

NewWriter creates an ObjectWriter for writing to the repository.

func (*Manager) Open

func (om *Manager) Open(ctx context.Context, objectID ID) (Reader, error)

Open creates new ObjectReader for reading given object from a repository.

func (*Manager) VerifyObject

func (om *Manager) VerifyObject(ctx context.Context, oid ID) (int64, []string, error)

VerifyObject ensures that all objects backing ObjectID are present in the repository and returns the total length of the object and storage blocks of which it is composed.

type ManagerOptions

type ManagerOptions struct {
	Trace func(message string, args ...interface{})
}

ManagerOptions specifies object manager options.

type Reader

type Reader interface {
	io.Reader
	io.Seeker
	io.Closer
	Length() int64
}

Reader allows reading, seeking, getting the length of and closing of a repository object.

type Writer

type Writer interface {
	io.WriteCloser

	Result() (ID, error)
}

Writer allows writing content to the storage and supports automatic deduplication and encryption of written data.

type WriterOptions

type WriterOptions struct {
	Description string
	Prefix      string // empty string or a single-character ('g'..'z')
}

WriterOptions can be passed to Repository.NewWriter()