kubernetes/vendor/github.com/mxk/go-flowrate/flowrate/flowrate.go

type Monitor …

// New creates a new flow control monitor. Instantaneous transfer rate is
// measured and updated for each sampleRate interval. windowSize determines the
// weight of each sample in the exponential moving average (EMA) calculation.
// The exact formulas are:
//
// 	sampleTime = currentTime - prevSampleTime
// 	sampleRate = byteCount / sampleTime
// 	weight     = 1 - exp(-sampleTime/windowSize)
// 	newRate    = weight*sampleRate + (1-weight)*oldRate
//
// The default values for sampleRate and windowSize (if <= 0) are 100ms and 1s,
// respectively.
func New(sampleRate, windowSize time.Duration) *Monitor { … }

// Update records the transfer of n bytes and returns n. It should be called
// after each Read/Write operation, even if n is 0.
func (m *Monitor) Update(n int) int { … }

// IO is a convenience method intended to wrap io.Reader and io.Writer method
// execution. It calls m.Update(n) and then returns (n, err) unmodified.
func (m *Monitor) IO(n int, err error) (int, error) { … }

// Done marks the transfer as finished and prevents any further updates or
// limiting. Instantaneous and current transfer rates drop to 0. Update, IO, and
// Limit methods become NOOPs. It returns the total number of bytes transferred.
func (m *Monitor) Done() int64 { … }

const timeRemLimit …

type Status …

// Status returns current transfer status information. The returned value
// becomes static after a call to Done.
func (m *Monitor) Status() Status { … }

// Limit restricts the instantaneous (per-sample) data flow to rate bytes per
// second. It returns the maximum number of bytes (0 <= n <= want) that may be
// transferred immediately without exceeding the limit. If block == true, the
// call blocks until n > 0. want is returned unmodified if want < 1, rate < 1,
// or the transfer is inactive (after a call to Done).
//
// At least one byte is always allowed to be transferred in any given sampling
// period. Thus, if the sampling rate is 100ms, the lowest achievable flow rate
// is 10 bytes per second.
//
// For usage examples, see the implementation of Reader and Writer in io.go.
func (m *Monitor) Limit(want int, rate int64, block bool) (n int) { … }

// SetTransferSize specifies the total size of the data transfer, which allows
// the Monitor to calculate the overall progress and time to completion.
func (m *Monitor) SetTransferSize(bytes int64) { … }

// update accumulates the transferred byte count for the current sample until
// clock() - m.sLast >= m.sRate. The monitor status is updated once the current
// sample is done.
func (m *Monitor) update(n int) (now time.Duration) { … }

// reset clears the current sample state in preparation for the next sample.
func (m *Monitor) reset(sampleTime time.Duration) { … }

// waitNextSample sleeps for the remainder of the current sample. The lock is
// released and reacquired during the actual sleep period, so it's possible for
// the transfer to be inactive when this method returns.
func (m *Monitor) waitNextSample(now time.Duration) time.Duration { … }