[VOL-5486] Fix deprecated versions
Change-Id: If0b888d6c2f33b2f415c8b03b08dc994bb3df3f4
Signed-off-by: Abhay Kumar <abhay.kumar@radisys.com>
diff --git a/vendor/golang.org/x/time/rate/rate.go b/vendor/golang.org/x/time/rate/rate.go
new file mode 100644
index 0000000..93a798a
--- /dev/null
+++ b/vendor/golang.org/x/time/rate/rate.go
@@ -0,0 +1,419 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package rate provides a rate limiter.
+package rate
+
+import (
+ "context"
+ "fmt"
+ "math"
+ "sync"
+ "time"
+)
+
+// Limit defines the maximum frequency of some events.
+// Limit is represented as number of events per second.
+// A zero Limit allows no events.
+type Limit float64
+
+// Inf is the infinite rate limit; it allows all events (even if burst is zero).
+const Inf = Limit(math.MaxFloat64)
+
+// Every converts a minimum time interval between events to a Limit.
+func Every(interval time.Duration) Limit {
+ if interval <= 0 {
+ return Inf
+ }
+ return 1 / Limit(interval.Seconds())
+}
+
+// A Limiter controls how frequently events are allowed to happen.
+// It implements a "token bucket" of size b, initially full and refilled
+// at rate r tokens per second.
+// Informally, in any large enough time interval, the Limiter limits the
+// rate to r tokens per second, with a maximum burst size of b events.
+// As a special case, if r == Inf (the infinite rate), b is ignored.
+// See https://en.wikipedia.org/wiki/Token_bucket for more about token buckets.
+//
+// The zero value is a valid Limiter, but it will reject all events.
+// Use NewLimiter to create non-zero Limiters.
+//
+// Limiter has three main methods, Allow, Reserve, and Wait.
+// Most callers should use Wait.
+//
+// Each of the three methods consumes a single token.
+// They differ in their behavior when no token is available.
+// If no token is available, Allow returns false.
+// If no token is available, Reserve returns a reservation for a future token
+// and the amount of time the caller must wait before using it.
+// If no token is available, Wait blocks until one can be obtained
+// or its associated context.Context is canceled.
+//
+// The methods AllowN, ReserveN, and WaitN consume n tokens.
+//
+// Limiter is safe for simultaneous use by multiple goroutines.
+type Limiter struct {
+ mu sync.Mutex
+ limit Limit
+ burst int
+ tokens float64
+ // last is the last time the limiter's tokens field was updated
+ last time.Time
+ // lastEvent is the latest time of a rate-limited event (past or future)
+ lastEvent time.Time
+}
+
+// Limit returns the maximum overall event rate.
+func (lim *Limiter) Limit() Limit {
+ lim.mu.Lock()
+ defer lim.mu.Unlock()
+ return lim.limit
+}
+
+// Burst returns the maximum burst size. Burst is the maximum number of tokens
+// that can be consumed in a single call to Allow, Reserve, or Wait, so higher
+// Burst values allow more events to happen at once.
+// A zero Burst allows no events, unless limit == Inf.
+func (lim *Limiter) Burst() int {
+ lim.mu.Lock()
+ defer lim.mu.Unlock()
+ return lim.burst
+}
+
+// TokensAt returns the number of tokens available at time t.
+func (lim *Limiter) TokensAt(t time.Time) float64 {
+ lim.mu.Lock()
+ _, tokens := lim.advance(t) // does not mutate lim
+ lim.mu.Unlock()
+ return tokens
+}
+
+// Tokens returns the number of tokens available now.
+func (lim *Limiter) Tokens() float64 {
+ return lim.TokensAt(time.Now())
+}
+
+// NewLimiter returns a new Limiter that allows events up to rate r and permits
+// bursts of at most b tokens.
+func NewLimiter(r Limit, b int) *Limiter {
+ return &Limiter{
+ limit: r,
+ burst: b,
+ tokens: float64(b),
+ }
+}
+
+// Allow reports whether an event may happen now.
+func (lim *Limiter) Allow() bool {
+ return lim.AllowN(time.Now(), 1)
+}
+
+// AllowN reports whether n events may happen at time t.
+// Use this method if you intend to drop / skip events that exceed the rate limit.
+// Otherwise use Reserve or Wait.
+func (lim *Limiter) AllowN(t time.Time, n int) bool {
+ return lim.reserveN(t, n, 0).ok
+}
+
+// A Reservation holds information about events that are permitted by a Limiter to happen after a delay.
+// A Reservation may be canceled, which may enable the Limiter to permit additional events.
+type Reservation struct {
+ ok bool
+ lim *Limiter
+ tokens int
+ timeToAct time.Time
+ // This is the Limit at reservation time, it can change later.
+ limit Limit
+}
+
+// OK returns whether the limiter can provide the requested number of tokens
+// within the maximum wait time. If OK is false, Delay returns InfDuration, and
+// Cancel does nothing.
+func (r *Reservation) OK() bool {
+ return r.ok
+}
+
+// Delay is shorthand for DelayFrom(time.Now()).
+func (r *Reservation) Delay() time.Duration {
+ return r.DelayFrom(time.Now())
+}
+
+// InfDuration is the duration returned by Delay when a Reservation is not OK.
+const InfDuration = time.Duration(math.MaxInt64)
+
+// DelayFrom returns the duration for which the reservation holder must wait
+// before taking the reserved action. Zero duration means act immediately.
+// InfDuration means the limiter cannot grant the tokens requested in this
+// Reservation within the maximum wait time.
+func (r *Reservation) DelayFrom(t time.Time) time.Duration {
+ if !r.ok {
+ return InfDuration
+ }
+ delay := r.timeToAct.Sub(t)
+ if delay < 0 {
+ return 0
+ }
+ return delay
+}
+
+// Cancel is shorthand for CancelAt(time.Now()).
+func (r *Reservation) Cancel() {
+ r.CancelAt(time.Now())
+}
+
+// CancelAt indicates that the reservation holder will not perform the reserved action
+// and reverses the effects of this Reservation on the rate limit as much as possible,
+// considering that other reservations may have already been made.
+func (r *Reservation) CancelAt(t time.Time) {
+ if !r.ok {
+ return
+ }
+
+ r.lim.mu.Lock()
+ defer r.lim.mu.Unlock()
+
+ if r.lim.limit == Inf || r.tokens == 0 || r.timeToAct.Before(t) {
+ return
+ }
+
+ // calculate tokens to restore
+ // The duration between lim.lastEvent and r.timeToAct tells us how many tokens were reserved
+ // after r was obtained. These tokens should not be restored.
+ restoreTokens := float64(r.tokens) - r.limit.tokensFromDuration(r.lim.lastEvent.Sub(r.timeToAct))
+ if restoreTokens <= 0 {
+ return
+ }
+ // advance time to now
+ t, tokens := r.lim.advance(t)
+ // calculate new number of tokens
+ tokens += restoreTokens
+ if burst := float64(r.lim.burst); tokens > burst {
+ tokens = burst
+ }
+ // update state
+ r.lim.last = t
+ r.lim.tokens = tokens
+ if r.timeToAct == r.lim.lastEvent {
+ prevEvent := r.timeToAct.Add(r.limit.durationFromTokens(float64(-r.tokens)))
+ if !prevEvent.Before(t) {
+ r.lim.lastEvent = prevEvent
+ }
+ }
+}
+
+// Reserve is shorthand for ReserveN(time.Now(), 1).
+func (lim *Limiter) Reserve() *Reservation {
+ return lim.ReserveN(time.Now(), 1)
+}
+
+// ReserveN returns a Reservation that indicates how long the caller must wait before n events happen.
+// The Limiter takes this Reservation into account when allowing future events.
+// The returned Reservation’s OK() method returns false if n exceeds the Limiter's burst size.
+// Usage example:
+//
+// r := lim.ReserveN(time.Now(), 1)
+// if !r.OK() {
+// // Not allowed to act! Did you remember to set lim.burst to be > 0 ?
+// return
+// }
+// time.Sleep(r.Delay())
+// Act()
+//
+// Use this method if you wish to wait and slow down in accordance with the rate limit without dropping events.
+// If you need to respect a deadline or cancel the delay, use Wait instead.
+// To drop or skip events exceeding rate limit, use Allow instead.
+func (lim *Limiter) ReserveN(t time.Time, n int) *Reservation {
+ r := lim.reserveN(t, n, InfDuration)
+ return &r
+}
+
+// Wait is shorthand for WaitN(ctx, 1).
+func (lim *Limiter) Wait(ctx context.Context) (err error) {
+ return lim.WaitN(ctx, 1)
+}
+
+// WaitN blocks until lim permits n events to happen.
+// It returns an error if n exceeds the Limiter's burst size, the Context is
+// canceled, or the expected wait time exceeds the Context's Deadline.
+// The burst limit is ignored if the rate limit is Inf.
+func (lim *Limiter) WaitN(ctx context.Context, n int) (err error) {
+ // The test code calls lim.wait with a fake timer generator.
+ // This is the real timer generator.
+ newTimer := func(d time.Duration) (<-chan time.Time, func() bool, func()) {
+ timer := time.NewTimer(d)
+ return timer.C, timer.Stop, func() {}
+ }
+
+ return lim.wait(ctx, n, time.Now(), newTimer)
+}
+
+// wait is the internal implementation of WaitN.
+func (lim *Limiter) wait(ctx context.Context, n int, t time.Time, newTimer func(d time.Duration) (<-chan time.Time, func() bool, func())) error {
+ lim.mu.Lock()
+ burst := lim.burst
+ limit := lim.limit
+ lim.mu.Unlock()
+
+ if n > burst && limit != Inf {
+ return fmt.Errorf("rate: Wait(n=%d) exceeds limiter's burst %d", n, burst)
+ }
+ // Check if ctx is already cancelled
+ select {
+ case <-ctx.Done():
+ return ctx.Err()
+ default:
+ }
+ // Determine wait limit
+ waitLimit := InfDuration
+ if deadline, ok := ctx.Deadline(); ok {
+ waitLimit = deadline.Sub(t)
+ }
+ // Reserve
+ r := lim.reserveN(t, n, waitLimit)
+ if !r.ok {
+ return fmt.Errorf("rate: Wait(n=%d) would exceed context deadline", n)
+ }
+ // Wait if necessary
+ delay := r.DelayFrom(t)
+ if delay == 0 {
+ return nil
+ }
+ ch, stop, advance := newTimer(delay)
+ defer stop()
+ advance() // only has an effect when testing
+ select {
+ case <-ch:
+ // We can proceed.
+ return nil
+ case <-ctx.Done():
+ // Context was canceled before we could proceed. Cancel the
+ // reservation, which may permit other events to proceed sooner.
+ r.Cancel()
+ return ctx.Err()
+ }
+}
+
+// SetLimit is shorthand for SetLimitAt(time.Now(), newLimit).
+func (lim *Limiter) SetLimit(newLimit Limit) {
+ lim.SetLimitAt(time.Now(), newLimit)
+}
+
+// SetLimitAt sets a new Limit for the limiter. The new Limit, and Burst, may be violated
+// or underutilized by those which reserved (using Reserve or Wait) but did not yet act
+// before SetLimitAt was called.
+func (lim *Limiter) SetLimitAt(t time.Time, newLimit Limit) {
+ lim.mu.Lock()
+ defer lim.mu.Unlock()
+
+ t, tokens := lim.advance(t)
+
+ lim.last = t
+ lim.tokens = tokens
+ lim.limit = newLimit
+}
+
+// SetBurst is shorthand for SetBurstAt(time.Now(), newBurst).
+func (lim *Limiter) SetBurst(newBurst int) {
+ lim.SetBurstAt(time.Now(), newBurst)
+}
+
+// SetBurstAt sets a new burst size for the limiter.
+func (lim *Limiter) SetBurstAt(t time.Time, newBurst int) {
+ lim.mu.Lock()
+ defer lim.mu.Unlock()
+
+ t, tokens := lim.advance(t)
+
+ lim.last = t
+ lim.tokens = tokens
+ lim.burst = newBurst
+}
+
+// reserveN is a helper method for AllowN, ReserveN, and WaitN.
+// maxFutureReserve specifies the maximum reservation wait duration allowed.
+// reserveN returns Reservation, not *Reservation, to avoid allocation in AllowN and WaitN.
+func (lim *Limiter) reserveN(t time.Time, n int, maxFutureReserve time.Duration) Reservation {
+ lim.mu.Lock()
+ defer lim.mu.Unlock()
+
+ if lim.limit == Inf {
+ return Reservation{
+ ok: true,
+ lim: lim,
+ tokens: n,
+ timeToAct: t,
+ }
+ }
+
+ t, tokens := lim.advance(t)
+
+ // Calculate the remaining number of tokens resulting from the request.
+ tokens -= float64(n)
+
+ // Calculate the wait duration
+ var waitDuration time.Duration
+ if tokens < 0 {
+ waitDuration = lim.limit.durationFromTokens(-tokens)
+ }
+
+ // Decide result
+ ok := n <= lim.burst && waitDuration <= maxFutureReserve
+
+ // Prepare reservation
+ r := Reservation{
+ ok: ok,
+ lim: lim,
+ limit: lim.limit,
+ }
+ if ok {
+ r.tokens = n
+ r.timeToAct = t.Add(waitDuration)
+
+ // Update state
+ lim.last = t
+ lim.tokens = tokens
+ lim.lastEvent = r.timeToAct
+ }
+
+ return r
+}
+
+// advance calculates and returns an updated state for lim resulting from the passage of time.
+// lim is not changed.
+// advance requires that lim.mu is held.
+func (lim *Limiter) advance(t time.Time) (newT time.Time, newTokens float64) {
+ last := lim.last
+ if t.Before(last) {
+ last = t
+ }
+
+ // Calculate the new number of tokens, due to time that passed.
+ elapsed := t.Sub(last)
+ delta := lim.limit.tokensFromDuration(elapsed)
+ tokens := lim.tokens + delta
+ if burst := float64(lim.burst); tokens > burst {
+ tokens = burst
+ }
+ return t, tokens
+}
+
+// durationFromTokens is a unit conversion function from the number of tokens to the duration
+// of time it takes to accumulate them at a rate of limit tokens per second.
+func (limit Limit) durationFromTokens(tokens float64) time.Duration {
+ if limit <= 0 {
+ return InfDuration
+ }
+ seconds := tokens / float64(limit)
+ return time.Duration(float64(time.Second) * seconds)
+}
+
+// tokensFromDuration is a unit conversion function from a time duration to the number of tokens
+// which could be accumulated during that duration at a rate of limit tokens per second.
+func (limit Limit) tokensFromDuration(d time.Duration) float64 {
+ if limit <= 0 {
+ return 0
+ }
+ return d.Seconds() * float64(limit)
+}