backoff

package
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Published: Oct 12, 2023 License: MIT Imports: 12 Imported by: 0

Documentation

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func FullJitter

func FullJitter(duration, min, max time.Duration, rng *rand.Rand) time.Duration

FullJitter returns a random number, uniformly chosen from the range [min, boundedDur]. boundedDur is the duration bounded between min and max.

func NewBackoffDiscovery

func NewBackoffDiscovery(disc discovery.Discovery, stratFactory BackoffFactory, opts ...BackoffDiscoveryOption) (discovery.Discovery, error)

func NoJitter

func NoJitter(duration, min, max time.Duration, rng *rand.Rand) time.Duration

NoJitter returns the duration bounded between min and max

Types

type BackoffConnector

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

BackoffConnector is a utility to connect to peers, but only if we have not recently tried connecting to them already

func NewBackoffConnector

func NewBackoffConnector(h host.Host, cacheSize int, connectionTryDuration time.Duration, backoff BackoffFactory) (*BackoffConnector, error)

NewBackoffConnector creates a utility to connect to peers, but only if we have not recently tried connecting to them already cacheSize is the size of a TwoQueueCache connectionTryDuration is how long we attempt to connect to a peer before giving up backoff describes the strategy used to decide how long to backoff after previously attempting to connect to a peer

func (*BackoffConnector) Connect

func (c *BackoffConnector) Connect(ctx context.Context, peerCh <-chan peer.AddrInfo)

Connect attempts to connect to the peers passed in by peerCh. Will not connect to peers if they are within the backoff period. As Connect will attempt to dial peers as soon as it learns about them, the caller should try to keep the number, and rate, of inbound peers manageable.

type BackoffDiscovery

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

BackoffDiscovery is an implementation of discovery that caches peer data and attenuates repeated queries

func (*BackoffDiscovery) Advertise

func (d *BackoffDiscovery) Advertise(ctx context.Context, ns string, opts ...discovery.Option) (time.Duration, error)

func (*BackoffDiscovery) FindPeers

func (d *BackoffDiscovery) FindPeers(ctx context.Context, ns string, opts ...discovery.Option) (<-chan peer.AddrInfo, error)

type BackoffDiscoveryOption

type BackoffDiscoveryOption func(*BackoffDiscovery) error

func WithBackoffDiscoveryReturnedChannelSize

func WithBackoffDiscoveryReturnedChannelSize(size int) BackoffDiscoveryOption

WithBackoffDiscoveryReturnedChannelSize sets the size of the buffer to be used during a FindPeer query. Note: This does not apply if the query occurs during the backoff time

func WithBackoffDiscoverySimultaneousQueryBufferSize

func WithBackoffDiscoverySimultaneousQueryBufferSize(size int) BackoffDiscoveryOption

WithBackoffDiscoverySimultaneousQueryBufferSize sets the buffer size for the channels between the main FindPeers query for a given namespace and all simultaneous FindPeers queries for the namespace

type BackoffFactory

type BackoffFactory func() BackoffStrategy

func NewExponentialBackoff

func NewExponentialBackoff(min, max time.Duration, jitter Jitter,
	timeUnits time.Duration, base float64, offset time.Duration, rngSrc rand.Source) BackoffFactory

NewExponentialBackoff creates a BackoffFactory with backoff of the form base^x + offset where x is the attempt number jitter is the function for adding randomness around the backoff timeUnits are the units of time the base^x is evaluated in

func NewExponentialDecorrelatedJitter

func NewExponentialDecorrelatedJitter(min, max time.Duration, base float64, rngSrc rand.Source) BackoffFactory

NewExponentialDecorrelatedJitter creates a BackoffFactory with backoff of the roughly of the form base^x where x is the attempt number. Delays start at the minimum duration and after each attempt delay = rand(min, delay * base), bounded by the max See https://aws.amazon.com/blogs/architecture/exponential-backoff-and-jitter/ for more information

func NewFixedBackoff

func NewFixedBackoff(delay time.Duration) BackoffFactory

NewFixedBackoff creates a BackoffFactory with a constant backoff duration

func NewPolynomialBackoff

func NewPolynomialBackoff(min, max time.Duration, jitter Jitter,
	timeUnits time.Duration, polyCoefs []float64, rngSrc rand.Source) BackoffFactory

NewPolynomialBackoff creates a BackoffFactory with backoff of the form c0*x^0, c1*x^1, ...cn*x^n where x is the attempt number jitter is the function for adding randomness around the backoff timeUnits are the units of time the polynomial is evaluated in polyCoefs is the array of polynomial coefficients from [c0, c1, ... cn]

type BackoffStrategy

type BackoffStrategy interface {
	// Delay calculates how long the next backoff duration should be, given the prior calls to Delay
	Delay() time.Duration
	// Reset clears the internal state of the BackoffStrategy
	Reset()
}

BackoffStrategy describes how backoff will be implemented. BackoffStrategies are stateful.

type Jitter

type Jitter func(duration, min, max time.Duration, rng *rand.Rand) time.Duration

Jitter must return a duration between min and max. Min must be lower than, or equal to, max.

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