flowcontrol

Documentation

Index

• type Backoff
  • func NewBackOff(initial, max time.Duration) *Backoff
  • func NewFakeBackOff(initial, max time.Duration, tc *clock.FakeClock) *Backoff
  • func (p *Backoff) DeleteEntry(id string)
  • func (p *Backoff) GC()
  • func (p *Backoff) Get(id string) time.Duration
  • func (p *Backoff) IsInBackOffSince(id string, eventTime time.Time) bool
  • func (p *Backoff) IsInBackOffSinceUpdate(id string, eventTime time.Time) bool
  • func (p *Backoff) Next(id string, eventTime time.Time)
  • func (p *Backoff) Reset(id string)
• type Clock
• type RateLimiter
  • func NewFakeAlwaysRateLimiter() RateLimiter
  • func NewFakeNeverRateLimiter() RateLimiter
  • func NewTokenBucketRateLimiter(qps float32, burst int) RateLimiter
  • func NewTokenBucketRateLimiterWithClock(qps float32, burst int, c Clock) RateLimiter

Types

type Backoff

type Backoff struct {
	sync.RWMutex
	Clock clock.Clock
	// contains filtered or unexported fields
}

func NewBackOff

func NewBackOff(initial, max time.Duration) *Backoff

func NewFakeBackOff

func NewFakeBackOff(initial, max time.Duration, tc *clock.FakeClock) *Backoff

func (*Backoff) DeleteEntry

func (p *Backoff) DeleteEntry(id string)

func (*Backoff) GC

func (p *Backoff) GC()

Garbage collect records that have aged past maxDuration. Backoff users are expected to invoke this periodically.

func (*Backoff) Get

func (p *Backoff) Get(id string) time.Duration

Get the current backoff Duration

func (*Backoff) IsInBackOffSince

func (p *Backoff) IsInBackOffSince(id string, eventTime time.Time) bool

Returns True if the elapsed time since eventTime is smaller than the current backoff window

func (*Backoff) IsInBackOffSinceUpdate

func (p *Backoff) IsInBackOffSinceUpdate(id string, eventTime time.Time) bool

Returns True if time since lastupdate is less than the current backoff window.

func (*Backoff) Next

func (p *Backoff) Next(id string, eventTime time.Time)

move backoff to the next mark, capping at maxDuration

func (*Backoff) Reset

func (p *Backoff) Reset(id string)

Reset forces clearing of all backoff data for a given key.

type Clock

type Clock interface {
	Now() time.Time
	Sleep(time.Duration)
}

An injectable, mockable clock interface.

type RateLimiter

type RateLimiter interface {
	// TryAccept returns true if a token is taken immediately. Otherwise,
	// it returns false.
	TryAccept() bool
	// Accept returns once a token becomes available.
	Accept()
	// Stop stops the rate limiter, subsequent calls to CanAccept will return false
	Stop()
	// QPS returns QPS of this rate limiter
	QPS() float32
	// Wait returns nil if a token is taken before the Context is done.
	Wait(ctx context.Context) error
}

func NewFakeAlwaysRateLimiter

func NewFakeAlwaysRateLimiter() RateLimiter

func NewFakeNeverRateLimiter

func NewFakeNeverRateLimiter() RateLimiter

func NewTokenBucketRateLimiter

func NewTokenBucketRateLimiter(qps float32, burst int) RateLimiter

NewTokenBucketRateLimiter creates a rate limiter which implements a token bucket approach. The rate limiter allows bursts of up to 'burst' to exceed the QPS, while still maintaining a smoothed qps rate of 'qps'. The bucket is initially filled with 'burst' tokens, and refills at a rate of 'qps'. The maximum number of tokens in the bucket is capped at 'burst'.

func NewTokenBucketRateLimiterWithClock

func NewTokenBucketRateLimiterWithClock(qps float32, burst int, c Clock) RateLimiter

NewTokenBucketRateLimiterWithClock is identical to NewTokenBucketRateLimiter but allows an injectable clock, for testing.