cas

Documentation

Overview

Package cas stores data in in a backing blob store with content-addressed storage and convergent encryption. That is, objects with with identical contents (using the same secret) have identical blob key and ciphertext.

Stored data is identified by a keyed hash of the plaintext data. Contents are encrypted with AEAD. All keys used are derived from the user-controlled secret by Argon2 KDFs.

Limitations

- No key rotation (at this level) - No garbage collection (at this level)

Index

• Variables
• type Extent
  • func (e *Extent) Bytes() ([]byte, error)
  • func (e *Extent) End() int64
  • func (e *Extent) Key() string
  • func (e *Extent) Next() (_ *Extent, ok bool)
  • func (e *Extent) Start() int64
• type Handle
  • func (h *Handle) IO(ctx context.Context) *Reader
  • func (h *Handle) Size() int64
• type Option
  • func WithChunkGoal(size uint32) Option
  • func WithChunkLimits(min, max uint32) Option
• type Reader
  • func (r *Reader) ExtentAt(offset int64) (*Extent, error)
  • func (r *Reader) Read(p []byte) (int, error)
  • func (r *Reader) ReadAt(p []byte, offset int64) (int, error)
• type Store
  • func NewStore(bucket *blob.Bucket, sharingPassphrase string, opts ...Option) *Store
  • func (s *Store) Create(ctx context.Context, r io.Reader) (string, error)
  • func (s *Store) DebugBoxKey(key string) (string, error)
  • func (s *Store) DebugReadBlob(ctx context.Context, blobKey string) ([]byte, error)
  • func (s *Store) Open(ctx context.Context, key string) (*Handle, error)
• type UnexpectedContentTypeError
  • func (u *UnexpectedContentTypeError) Error() string

Variables

var (
	ErrBadKey      = errors.New("bad key")
	ErrNotExist    = errors.New("object does not exist")
	ErrCorruptBlob = errors.New("blob is corrupted")
)

Types

type Extent

type Extent struct {
	// contains filtered or unexported fields
}

func (*Extent) Bytes

func (e *Extent) Bytes() ([]byte, error)

func (*Extent) End

func (e *Extent) End() int64

func (*Extent) Key

func (e *Extent) Key() string

func (*Extent) Next

func (e *Extent) Next() (_ *Extent, ok bool)

func (*Extent) Start

func (e *Extent) Start() int64

type Handle

type Handle struct {
	// contains filtered or unexported fields
}

func (*Handle) IO

func (h *Handle) IO(ctx context.Context) *Reader

func (*Handle) Size

func (h *Handle) Size() int64

type Option

type Option option

func WithChunkGoal

func WithChunkGoal(size uint32) Option

WithChunkGoal sets the desired average chunk size for chunking.

Zero will leave the previous value in effect.

func WithChunkLimits

func WithChunkLimits(min, max uint32) Option

WithChunkLimits sets the minimum and maximum chunk size.

Zero will leave the previous value in effect.

An invalid combination (min > max, including when one is left to zero and uses the previous value) will set both values to max.

type Reader

type Reader struct {
	// contains filtered or unexported fields
}

func (*Reader) ExtentAt

func (r *Reader) ExtentAt(offset int64) (*Extent, error)

ExtentAt returns the extent containing offset, or io.EOF if offset is outside of stored data.

Note that the extent starting offset can be (and typically is) before the requested offset.

func (*Reader) Read

func (r *Reader) Read(p []byte) (int, error)

func (*Reader) ReadAt

func (r *Reader) ReadAt(p []byte, offset int64) (int, error)

type Store

type Store struct {
	// contains filtered or unexported fields
}

func NewStore

func NewStore(bucket *blob.Bucket, sharingPassphrase string, opts ...Option) *Store

func (*Store) Create

func (s *Store) Create(ctx context.Context, r io.Reader) (string, error)

func (*Store) DebugBoxKey

func (s *Store) DebugBoxKey(key string) (string, error)

func (*Store) DebugReadBlob

func (s *Store) DebugReadBlob(ctx context.Context, blobKey string) ([]byte, error)

func (*Store) Open

func (s *Store) Open(ctx context.Context, key string) (*Handle, error)

type UnexpectedContentTypeError

type UnexpectedContentTypeError struct {
	ContentType string
}

func (*UnexpectedContentTypeError) Error

func (u *UnexpectedContentTypeError) Error() string