light

Documentation

Overview

TODO(@Wondertan): Instead of doing sampling over the coordinates do a random walk over NMT trees.

Index

• Variables
• func EmptyGetter() (share.Getter, blockservice.BlockService)
• func GetterWithRandSquare(t *testing.T, n int) (share.Getter, *share.Root)
• func Node(dn *availability_test.TestDagNet) *availability_test.TestNode
• func RandNode(dn *availability_test.TestDagNet, squareSize int) (*availability_test.TestNode, *share.Root)
• func SubNetNode(sn *availability_test.SubNet) *availability_test.TestNode
• type Option
  • func WithSampleAmount(sampleAmount uint) Option
• type Parameters
  • func DefaultParameters() Parameters
  • func (p *Parameters) Validate() error
• type Sample
  • func SampleSquare(squareWidth int, num int) ([]Sample, error)
• type ShareAvailability
  • func NewShareAvailability(getter share.Getter, ds datastore.Batching, opts ...Option) *ShareAvailability
  • func TestAvailability(getter share.Getter) *ShareAvailability
  • func (la *ShareAvailability) Close(ctx context.Context) error
  • func (la *ShareAvailability) ProbabilityOfAvailability(context.Context) float64
  • func (la *ShareAvailability) SharesAvailable(ctx context.Context, dah *share.Root) error

Variables

var (
	DefaultSampleAmount uint = 16
)

SampleAmount specifies the minimum required amount of samples a light node must perform before declaring that a block is available

Functions

func EmptyGetter

func EmptyGetter() (share.Getter, blockservice.BlockService)

EmptyGetter provides an unfilled share.Getter with corresponding blockservice.BlockService than can be filled by the test.

func GetterWithRandSquare

func GetterWithRandSquare(t *testing.T, n int) (share.Getter, *share.Root)

GetterWithRandSquare provides a share.Getter filled with 'n' NMT trees of 'n' random shares, essentially storing a whole square.

func Node

func Node(dn *availability_test.TestDagNet) *availability_test.TestNode

Node creates a new empty Light Node.

func RandNode

func RandNode(dn *availability_test.TestDagNet, squareSize int) (*availability_test.TestNode, *share.Root)

RandNode creates a Light Node filled with a random block of the given size.

func SubNetNode

func SubNetNode(sn *availability_test.SubNet) *availability_test.TestNode

Types

type Option

type Option func(*Parameters)

Option is a function that configures light availability Parameters

func WithSampleAmount

func WithSampleAmount(sampleAmount uint) Option

WithSampleAmount is a functional option that the Availability interface implementers use to set the SampleAmount configuration param

type Parameters

type Parameters struct {
	SampleAmount uint // The minimum required amount of samples to perform
}

Parameters is the set of Parameters that must be configured for the light availability implementation

func DefaultParameters

func DefaultParameters() Parameters

DefaultParameters returns the default Parameters' configuration values for the light availability implementation

func (*Parameters) Validate

func (p *Parameters) Validate() error

Validate validates the values in Parameters

type Sample

type Sample struct {
	Row, Col int
}

Sample is a point in 2D space over square.

func SampleSquare

func SampleSquare(squareWidth int, num int) ([]Sample, error)

SampleSquare randomly picks *num* unique points from the given *width* square and returns them as samples.

type ShareAvailability

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

ShareAvailability implements share.Availability using Data Availability Sampling technique. It is light because it does not require the downloading of all the data to verify its availability. It is assumed that there are a lot of lightAvailability instances on the network doing sampling over the same Root to collectively verify its availability.

func NewShareAvailability

func NewShareAvailability(
	getter share.Getter,
	ds datastore.Batching,
	opts ...Option,
) *ShareAvailability

NewShareAvailability creates a new light Availability.

func TestAvailability

func TestAvailability(getter share.Getter) *ShareAvailability

func (*ShareAvailability) Close

func (la *ShareAvailability) Close(ctx context.Context) error

Close flushes all queued writes to disk.

func (*ShareAvailability) ProbabilityOfAvailability

func (la *ShareAvailability) ProbabilityOfAvailability(context.Context) float64

ProbabilityOfAvailability calculates the probability that the data square is available based on the amount of samples collected (params.SampleAmount).

Formula: 1 - (0.75 ** amount of samples)

func (*ShareAvailability) SharesAvailable

func (la *ShareAvailability) SharesAvailable(ctx context.Context, dah *share.Root) error

SharesAvailable randomly samples `params.SampleAmount` amount of Shares committed to the given Root. This way SharesAvailable subjectively verifies that Shares are available.