update kube and vendor dependencies

With kubernetes 1.18 release of client-go, signatures on methods in
generated clientsets, dynamic, metadata, and scale clients have been
modified to accept context.Context as a first argument.
Signatures of Create, Update, and Patch methods have been updated
to accept CreateOptions, UpdateOptions and PatchOptions respectively.
Signatures of Delete and DeleteCollection methods now accept
DeleteOptions by value instead of by reference.
These changes are now accommodated with this PR and client-go
and dependencies are updated to v1.18.0

Signed-off-by: Humble Chirammal <hchiramm@redhat.com>

vendor/k8s.io/apimachinery/pkg/util/clock/clock.go

@@ -52,23 +52,26 @@ func (RealClock) Since(ts time.Time) time.Duration {
 	return time.Since(ts)
 }
 
-// Same as time.After(d).
+// After is the same as time.After(d).
 func (RealClock) After(d time.Duration) <-chan time.Time {
 	return time.After(d)
 }
 
+// NewTimer returns a new Timer.
 func (RealClock) NewTimer(d time.Duration) Timer {
 	return &realTimer{
 		timer: time.NewTimer(d),
 	}
 }
 
+// NewTicker returns a new Ticker.
 func (RealClock) NewTicker(d time.Duration) Ticker {
 	return &realTicker{
 		ticker: time.NewTicker(d),
 	}
 }
 
+// Sleep pauses the RealClock for duration d.
 func (RealClock) Sleep(d time.Duration) {
 	time.Sleep(d)
 }
@@ -94,12 +97,14 @@ type fakeClockWaiter struct {
 	destChan      chan time.Time
 }
 
+// NewFakePassiveClock returns a new FakePassiveClock.
 func NewFakePassiveClock(t time.Time) *FakePassiveClock {
 	return &FakePassiveClock{
 		time: t,
 	}
 }
 
+// NewFakeClock returns a new FakeClock
 func NewFakeClock(t time.Time) *FakeClock {
 	return &FakeClock{
 		FakePassiveClock: *NewFakePassiveClock(t),
@@ -120,14 +125,14 @@ func (f *FakePassiveClock) Since(ts time.Time) time.Duration {
 	return f.time.Sub(ts)
 }
 
-// Sets the time.
+// SetTime sets the time on the FakePassiveClock.
 func (f *FakePassiveClock) SetTime(t time.Time) {
 	f.lock.Lock()
 	defer f.lock.Unlock()
 	f.time = t
 }
 
-// Fake version of time.After(d).
+// After is the Fake version of time.After(d).
 func (f *FakeClock) After(d time.Duration) <-chan time.Time {
 	f.lock.Lock()
 	defer f.lock.Unlock()
@@ -140,7 +145,7 @@ func (f *FakeClock) After(d time.Duration) <-chan time.Time {
 	return ch
 }
 
-// Fake version of time.NewTimer(d).
+// NewTimer is the Fake version of time.NewTimer(d).
 func (f *FakeClock) NewTimer(d time.Duration) Timer {
 	f.lock.Lock()
 	defer f.lock.Unlock()
@@ -157,6 +162,7 @@ func (f *FakeClock) NewTimer(d time.Duration) Timer {
 	return timer
 }
 
+// NewTicker returns a new Ticker.
 func (f *FakeClock) NewTicker(d time.Duration) Ticker {
 	f.lock.Lock()
 	defer f.lock.Unlock()
@@ -174,14 +180,14 @@ func (f *FakeClock) NewTicker(d time.Duration) Ticker {
 	}
 }
 
-// Move clock by Duration, notify anyone that's called After, Tick, or NewTimer
+// Step moves clock by Duration, notifies anyone that's called After, Tick, or NewTimer
 func (f *FakeClock) Step(d time.Duration) {
 	f.lock.Lock()
 	defer f.lock.Unlock()
 	f.setTimeLocked(f.time.Add(d))
 }
 
-// Sets the time.
+// SetTime sets the time on a FakeClock.
 func (f *FakeClock) SetTime(t time.Time) {
 	f.lock.Lock()
 	defer f.lock.Unlock()
@@ -219,7 +225,7 @@ func (f *FakeClock) setTimeLocked(t time.Time) {
 	f.waiters = newWaiters
 }
 
-// Returns true if After has been called on f but not yet satisfied (so you can
+// HasWaiters returns true if After has been called on f but not yet satisfied (so you can
 // write race-free tests).
 func (f *FakeClock) HasWaiters() bool {
 	f.lock.RLock()
@@ -227,6 +233,7 @@ func (f *FakeClock) HasWaiters() bool {
 	return len(f.waiters) > 0
 }
 
+// Sleep pauses the FakeClock for duration d.
 func (f *FakeClock) Sleep(d time.Duration) {
 	f.Step(d)
 }
@@ -248,24 +255,25 @@ func (i *IntervalClock) Since(ts time.Time) time.Duration {
 	return i.Time.Sub(ts)
 }
 
-// Unimplemented, will panic.
+// After is currently unimplemented, will panic.
 // TODO: make interval clock use FakeClock so this can be implemented.
 func (*IntervalClock) After(d time.Duration) <-chan time.Time {
 	panic("IntervalClock doesn't implement After")
 }
 
-// Unimplemented, will panic.
+// NewTimer is currently unimplemented, will panic.
 // TODO: make interval clock use FakeClock so this can be implemented.
 func (*IntervalClock) NewTimer(d time.Duration) Timer {
 	panic("IntervalClock doesn't implement NewTimer")
 }
 
-// Unimplemented, will panic.
+// NewTicker is currently unimplemented, will panic.
 // TODO: make interval clock use FakeClock so this can be implemented.
 func (*IntervalClock) NewTicker(d time.Duration) Ticker {
 	panic("IntervalClock doesn't implement NewTicker")
 }
 
+// Sleep is currently unimplemented; will panic.
 func (*IntervalClock) Sleep(d time.Duration) {
 	panic("IntervalClock doesn't implement Sleep")
 }
@@ -355,6 +363,7 @@ func (f *fakeTimer) Reset(d time.Duration) bool {
 	return false
 }
 
+// Ticker defines the Ticker interface
 type Ticker interface {
 	C() <-chan time.Time
 	Stop()

vendor/k8s.io/apimachinery/pkg/util/errors/errors.go

@@ -28,9 +28,14 @@ type MessageCountMap map[string]int
 
 // Aggregate represents an object that contains multiple errors, but does not
 // necessarily have singular semantic meaning.
+// The aggregate can be used with `errors.Is()` to check for the occurrence of
+// a specific error type.
+// Errors.As() is not supported, because the caller presumably cares about a
+// specific error of potentially multiple that match the given type.
 type Aggregate interface {
 	error
 	Errors() []error
+	Is(error) bool
 }
 
 // NewAggregate converts a slice of errors into an Aggregate interface, which
@@ -71,16 +76,17 @@ func (agg aggregate) Error() string {
 	}
 	seenerrs := sets.NewString()
 	result := ""
-	agg.visit(func(err error) {
+	agg.visit(func(err error) bool {
 		msg := err.Error()
 		if seenerrs.Has(msg) {
-			return
+			return false
 		}
 		seenerrs.Insert(msg)
 		if len(seenerrs) > 1 {
 			result += ", "
 		}
 		result += msg
+		return false
 	})
 	if len(seenerrs) == 1 {
 		return result
@@ -88,19 +94,33 @@ func (agg aggregate) Error() string {
 	return "[" + result + "]"
 }
 
-func (agg aggregate) visit(f func(err error)) {
+func (agg aggregate) Is(target error) bool {
+	return agg.visit(func(err error) bool {
+		return errors.Is(err, target)
+	})
+}
+
+func (agg aggregate) visit(f func(err error) bool) bool {
 	for _, err := range agg {
 		switch err := err.(type) {
 		case aggregate:
-			err.visit(f)
+			if match := err.visit(f); match {
+				return match
+			}
 		case Aggregate:
 			for _, nestedErr := range err.Errors() {
-				f(nestedErr)
+				if match := f(nestedErr); match {
+					return match
+				}
 			}
 		default:
-			f(err)
+			if match := f(err); match {
+				return match
+			}
 		}
 	}
+
+	return false
 }
 
 // Errors is part of the Aggregate interface.

vendor/k8s.io/apimachinery/pkg/util/intstr/generated.pb.go

@@ -38,7 +38,7 @@ var _ = math.Inf
 // is compatible with the proto package it is being compiled against.
 // A compilation error at this line likely means your copy of the
 // proto package needs to be updated.
-const _ = proto.GoGoProtoPackageIsVersion2 // please upgrade the proto package
+const _ = proto.GoGoProtoPackageIsVersion3 // please upgrade the proto package
 
 func (m *IntOrString) Reset()      { *m = IntOrString{} }
 func (*IntOrString) ProtoMessage() {}
@@ -289,6 +289,7 @@ func (m *IntOrString) Unmarshal(dAtA []byte) error {
 func skipGenerated(dAtA []byte) (n int, err error) {
 	l := len(dAtA)
 	iNdEx := 0
+	depth := 0
 	for iNdEx < l {
 		var wire uint64
 		for shift := uint(0); ; shift += 7 {
@@ -320,10 +321,8 @@ func skipGenerated(dAtA []byte) (n int, err error) {
 					break
 				}
 			}
-			return iNdEx, nil
 		case 1:
 			iNdEx += 8
-			return iNdEx, nil
 		case 2:
 			var length int
 			for shift := uint(0); ; shift += 7 {
@@ -344,55 +343,30 @@ func skipGenerated(dAtA []byte) (n int, err error) {
 				return 0, ErrInvalidLengthGenerated
 			}
 			iNdEx += length
-			if iNdEx < 0 {
-				return 0, ErrInvalidLengthGenerated
-			}
-			return iNdEx, nil
 		case 3:
-			for {
-				var innerWire uint64
-				var start int = iNdEx
-				for shift := uint(0); ; shift += 7 {
-					if shift >= 64 {
-						return 0, ErrIntOverflowGenerated
-					}
-					if iNdEx >= l {
-						return 0, io.ErrUnexpectedEOF
-					}
-					b := dAtA[iNdEx]
-					iNdEx++
-					innerWire |= (uint64(b) & 0x7F) << shift
-					if b < 0x80 {
-						break
-					}
-				}
-				innerWireType := int(innerWire & 0x7)
-				if innerWireType == 4 {
-					break
-				}
-				next, err := skipGenerated(dAtA[start:])
-				if err != nil {
-					return 0, err
-				}
-				iNdEx = start + next
-				if iNdEx < 0 {
-					return 0, ErrInvalidLengthGenerated
-				}
-			}
-			return iNdEx, nil
+			depth++
 		case 4:
-			return iNdEx, nil
+			if depth == 0 {
+				return 0, ErrUnexpectedEndOfGroupGenerated
+			}
+			depth--
 		case 5:
 			iNdEx += 4
-			return iNdEx, nil
 		default:
 			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
 		}
+		if iNdEx < 0 {
+			return 0, ErrInvalidLengthGenerated
+		}
+		if depth == 0 {
+			return iNdEx, nil
+		}
 	}
-	panic("unreachable")
+	return 0, io.ErrUnexpectedEOF
 }
 
 var (
-	ErrInvalidLengthGenerated = fmt.Errorf("proto: negative length found during unmarshaling")
-	ErrIntOverflowGenerated   = fmt.Errorf("proto: integer overflow")
+	ErrInvalidLengthGenerated        = fmt.Errorf("proto: negative length found during unmarshaling")
+	ErrIntOverflowGenerated          = fmt.Errorf("proto: integer overflow")
+	ErrUnexpectedEndOfGroupGenerated = fmt.Errorf("proto: unexpected end of group")
 )

vendor/k8s.io/apimachinery/pkg/util/intstr/intstr.go

@@ -97,7 +97,8 @@ func (intstr *IntOrString) String() string {
 }
 
 // IntValue returns the IntVal if type Int, or if
-// it is a String, will attempt a conversion to int.
+// it is a String, will attempt a conversion to int,
+// returning 0 if a parsing error occurs.
 func (intstr *IntOrString) IntValue() int {
 	if intstr.Type == String {
 		i, _ := strconv.Atoi(intstr.StrVal)

vendor/k8s.io/apimachinery/pkg/util/net/http.go

@@ -206,13 +206,17 @@ func GetHTTPClient(req *http.Request) string {
 	return "unknown"
 }
 
-// SourceIPs splits the comma separated X-Forwarded-For header or returns the X-Real-Ip header or req.RemoteAddr,
-// in that order, ignoring invalid IPs. It returns nil if all of these are empty or invalid.
+// SourceIPs splits the comma separated X-Forwarded-For header and joins it with
+// the X-Real-Ip header and/or req.RemoteAddr, ignoring invalid IPs.
+// The X-Real-Ip is omitted if it's already present in the X-Forwarded-For chain.
+// The req.RemoteAddr is always the last IP in the returned list.
+// It returns nil if all of these are empty or invalid.
 func SourceIPs(req *http.Request) []net.IP {
+	var srcIPs []net.IP
+
 	hdr := req.Header
 	// First check the X-Forwarded-For header for requests via proxy.
 	hdrForwardedFor := hdr.Get("X-Forwarded-For")
-	forwardedForIPs := []net.IP{}
 	if hdrForwardedFor != "" {
 		// X-Forwarded-For can be a csv of IPs in case of multiple proxies.
 		// Use the first valid one.
@@ -220,38 +224,49 @@ func SourceIPs(req *http.Request) []net.IP {
 		for _, part := range parts {
 			ip := net.ParseIP(strings.TrimSpace(part))
 			if ip != nil {
-				forwardedForIPs = append(forwardedForIPs, ip)
+				srcIPs = append(srcIPs, ip)
 			}
 		}
 	}
-	if len(forwardedForIPs) > 0 {
-		return forwardedForIPs
-	}
 
 	// Try the X-Real-Ip header.
 	hdrRealIp := hdr.Get("X-Real-Ip")
 	if hdrRealIp != "" {
 		ip := net.ParseIP(hdrRealIp)
-		if ip != nil {
-			return []net.IP{ip}
+		// Only append the X-Real-Ip if it's not already contained in the X-Forwarded-For chain.
+		if ip != nil && !containsIP(srcIPs, ip) {
+			srcIPs = append(srcIPs, ip)
 		}
 	}
 
-	// Fallback to Remote Address in request, which will give the correct client IP when there is no proxy.
+	// Always include the request Remote Address as it cannot be easily spoofed.
+	var remoteIP net.IP
 	// Remote Address in Go's HTTP server is in the form host:port so we need to split that first.
 	host, _, err := net.SplitHostPort(req.RemoteAddr)
 	if err == nil {
-		if remoteIP := net.ParseIP(host); remoteIP != nil {
-			return []net.IP{remoteIP}
+		remoteIP = net.ParseIP(host)
+	}
+	// Fallback if Remote Address was just IP.
+	if remoteIP == nil {
+		remoteIP = net.ParseIP(req.RemoteAddr)
+	}
+
+	// Don't duplicate remote IP if it's already the last address in the chain.
+	if remoteIP != nil && (len(srcIPs) == 0 || !remoteIP.Equal(srcIPs[len(srcIPs)-1])) {
+		srcIPs = append(srcIPs, remoteIP)
+	}
+
+	return srcIPs
+}
+
+// Checks whether the given IP address is contained in the list of IPs.
+func containsIP(ips []net.IP, ip net.IP) bool {
+	for _, v := range ips {
+		if v.Equal(ip) {
+			return true
 		}
 	}
-
-	// Fallback if Remote Address was just IP.
-	if remoteIP := net.ParseIP(req.RemoteAddr); remoteIP != nil {
-		return []net.IP{remoteIP}
-	}
-
-	return nil
+	return false
 }
 
 // Extracts and returns the clients IP from the given request.

vendor/k8s.io/apimachinery/pkg/util/rand/rand.go

@@ -1,127 +0,0 @@
-/*
-Copyright 2015 The Kubernetes Authors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-// Package rand provides utilities related to randomization.
-package rand
-
-import (
-	"math/rand"
-	"sync"
-	"time"
-)
-
-var rng = struct {
-	sync.Mutex
-	rand *rand.Rand
-}{
-	rand: rand.New(rand.NewSource(time.Now().UnixNano())),
-}
-
-// Int returns a non-negative pseudo-random int.
-func Int() int {
-	rng.Lock()
-	defer rng.Unlock()
-	return rng.rand.Int()
-}
-
-// Intn generates an integer in range [0,max).
-// By design this should panic if input is invalid, <= 0.
-func Intn(max int) int {
-	rng.Lock()
-	defer rng.Unlock()
-	return rng.rand.Intn(max)
-}
-
-// IntnRange generates an integer in range [min,max).
-// By design this should panic if input is invalid, <= 0.
-func IntnRange(min, max int) int {
-	rng.Lock()
-	defer rng.Unlock()
-	return rng.rand.Intn(max-min) + min
-}
-
-// IntnRange generates an int64 integer in range [min,max).
-// By design this should panic if input is invalid, <= 0.
-func Int63nRange(min, max int64) int64 {
-	rng.Lock()
-	defer rng.Unlock()
-	return rng.rand.Int63n(max-min) + min
-}
-
-// Seed seeds the rng with the provided seed.
-func Seed(seed int64) {
-	rng.Lock()
-	defer rng.Unlock()
-
-	rng.rand = rand.New(rand.NewSource(seed))
-}
-
-// Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n)
-// from the default Source.
-func Perm(n int) []int {
-	rng.Lock()
-	defer rng.Unlock()
-	return rng.rand.Perm(n)
-}
-
-const (
-	// We omit vowels from the set of available characters to reduce the chances
-	// of "bad words" being formed.
-	alphanums = "bcdfghjklmnpqrstvwxz2456789"
-	// No. of bits required to index into alphanums string.
-	alphanumsIdxBits = 5
-	// Mask used to extract last alphanumsIdxBits of an int.
-	alphanumsIdxMask = 1<<alphanumsIdxBits - 1
-	// No. of random letters we can extract from a single int63.
-	maxAlphanumsPerInt = 63 / alphanumsIdxBits
-)
-
-// String generates a random alphanumeric string, without vowels, which is n
-// characters long.  This will panic if n is less than zero.
-// How the random string is created:
-// - we generate random int63's
-// - from each int63, we are extracting multiple random letters by bit-shifting and masking
-// - if some index is out of range of alphanums we neglect it (unlikely to happen multiple times in a row)
-func String(n int) string {
-	b := make([]byte, n)
-	rng.Lock()
-	defer rng.Unlock()
-
-	randomInt63 := rng.rand.Int63()
-	remaining := maxAlphanumsPerInt
-	for i := 0; i < n; {
-		if remaining == 0 {
-			randomInt63, remaining = rng.rand.Int63(), maxAlphanumsPerInt
-		}
-		if idx := int(randomInt63 & alphanumsIdxMask); idx < len(alphanums) {
-			b[i] = alphanums[idx]
-			i++
-		}
-		randomInt63 >>= alphanumsIdxBits
-		remaining--
-	}
-	return string(b)
-}
-
-// SafeEncodeString encodes s using the same characters as rand.String. This reduces the chances of bad words and
-// ensures that strings generated from hash functions appear consistent throughout the API.
-func SafeEncodeString(s string) string {
-	r := make([]byte, len(s))
-	for i, b := range []rune(s) {
-		r[i] = alphanums[(int(b) % len(alphanums))]
-	}
-	return string(r)
-}

vendor/k8s.io/apimachinery/pkg/util/validation/validation.go

@@ -109,6 +109,44 @@ func IsFullyQualifiedDomainName(fldPath *field.Path, name string) field.ErrorLis
 	return allErrors
 }
 
+// Allowed characters in an HTTP Path as defined by RFC 3986. A HTTP path may
+// contain:
+// * unreserved characters (alphanumeric, '-', '.', '_', '~')
+// * percent-encoded octets
+// * sub-delims ("!", "$", "&", "'", "(", ")", "*", "+", ",", ";", "=")
+// * a colon character (":")
+const httpPathFmt string = `[A-Za-z0-9/\-._~%!$&'()*+,;=:]+`
+
+var httpPathRegexp = regexp.MustCompile("^" + httpPathFmt + "$")
+
+// IsDomainPrefixedPath checks if the given string is a domain-prefixed path
+// (e.g. acme.io/foo). All characters before the first "/" must be a valid
+// subdomain as defined by RFC 1123. All characters trailing the first "/" must
+// be valid HTTP Path characters as defined by RFC 3986.
+func IsDomainPrefixedPath(fldPath *field.Path, dpPath string) field.ErrorList {
+	var allErrs field.ErrorList
+	if len(dpPath) == 0 {
+		return append(allErrs, field.Required(fldPath, ""))
+	}
+
+	segments := strings.SplitN(dpPath, "/", 2)
+	if len(segments) != 2 || len(segments[0]) == 0 || len(segments[1]) == 0 {
+		return append(allErrs, field.Invalid(fldPath, dpPath, "must be a domain-prefixed path (such as \"acme.io/foo\")"))
+	}
+
+	host := segments[0]
+	for _, err := range IsDNS1123Subdomain(host) {
+		allErrs = append(allErrs, field.Invalid(fldPath, host, err))
+	}
+
+	path := segments[1]
+	if !httpPathRegexp.MatchString(path) {
+		return append(allErrs, field.Invalid(fldPath, path, RegexError("Invalid path", httpPathFmt)))
+	}
+
+	return allErrs
+}
+
 const labelValueFmt string = "(" + qualifiedNameFmt + ")?"
 const labelValueErrMsg string = "a valid label must be an empty string or consist of alphanumeric characters, '-', '_' or '.', and must start and end with an alphanumeric character"
 

vendor/k8s.io/apimachinery/pkg/util/wait/wait.go

@@ -19,10 +19,12 @@ package wait
 import (
 	"context"
 	"errors"
+	"math"
 	"math/rand"
 	"sync"
 	"time"
 
+	"k8s.io/apimachinery/pkg/util/clock"
 	"k8s.io/apimachinery/pkg/util/runtime"
 )
 
@@ -128,9 +130,15 @@ func NonSlidingUntilWithContext(ctx context.Context, f func(context.Context), pe
 // Close stopCh to stop. f may not be invoked if stop channel is already
 // closed. Pass NeverStop to if you don't want it stop.
 func JitterUntil(f func(), period time.Duration, jitterFactor float64, sliding bool, stopCh <-chan struct{}) {
-	var t *time.Timer
-	var sawTimeout bool
+	BackoffUntil(f, NewJitteredBackoffManager(period, jitterFactor, &clock.RealClock{}), sliding, stopCh)
+}
 
+// BackoffUntil loops until stop channel is closed, run f every duration given by BackoffManager.
+//
+// If sliding is true, the period is computed after f runs. If it is false then
+// period includes the runtime for f.
+func BackoffUntil(f func(), backoff BackoffManager, sliding bool, stopCh <-chan struct{}) {
+	var t clock.Timer
 	for {
 		select {
 		case <-stopCh:
@@ -138,13 +146,8 @@ func JitterUntil(f func(), period time.Duration, jitterFactor float64, sliding b
 		default:
 		}
 
-		jitteredPeriod := period
-		if jitterFactor > 0.0 {
-			jitteredPeriod = Jitter(period, jitterFactor)
-		}
-
 		if !sliding {
-			t = resetOrReuseTimer(t, jitteredPeriod, sawTimeout)
+			t = backoff.Backoff()
 		}
 
 		func() {
@@ -153,7 +156,7 @@ func JitterUntil(f func(), period time.Duration, jitterFactor float64, sliding b
 		}()
 
 		if sliding {
-			t = resetOrReuseTimer(t, jitteredPeriod, sawTimeout)
+			t = backoff.Backoff()
 		}
 
 		// NOTE: b/c there is no priority selection in golang
@@ -164,8 +167,7 @@ func JitterUntil(f func(), period time.Duration, jitterFactor float64, sliding b
 		select {
 		case <-stopCh:
 			return
-		case <-t.C:
-			sawTimeout = true
+		case <-t.C():
 		}
 	}
 }
@@ -203,6 +205,12 @@ var ErrWaitTimeout = errors.New("timed out waiting for the condition")
 // if the loop should be aborted.
 type ConditionFunc func() (done bool, err error)
 
+// runConditionWithCrashProtection runs a ConditionFunc with crash protection
+func runConditionWithCrashProtection(condition ConditionFunc) (bool, error) {
+	defer runtime.HandleCrash()
+	return condition()
+}
+
 // Backoff holds parameters applied to a Backoff function.
 type Backoff struct {
 	// The initial duration.
@@ -277,6 +285,92 @@ func contextForChannel(parentCh <-chan struct{}) (context.Context, context.Cance
 	return ctx, cancel
 }
 
+// BackoffManager manages backoff with a particular scheme based on its underlying implementation. It provides
+// an interface to return a timer for backoff, and caller shall backoff until Timer.C returns. If the second Backoff()
+// is called before the timer from the first Backoff() call finishes, the first timer will NOT be drained.
+// The BackoffManager is supposed to be called in a single-threaded environment.
+type BackoffManager interface {
+	Backoff() clock.Timer
+}
+
+type exponentialBackoffManagerImpl struct {
+	backoff              *Backoff
+	backoffTimer         clock.Timer
+	lastBackoffStart     time.Time
+	initialBackoff       time.Duration
+	backoffResetDuration time.Duration
+	clock                clock.Clock
+}
+
+// NewExponentialBackoffManager returns a manager for managing exponential backoff. Each backoff is jittered and
+// backoff will not exceed the given max. If the backoff is not called within resetDuration, the backoff is reset.
+// This backoff manager is used to reduce load during upstream unhealthiness.
+func NewExponentialBackoffManager(initBackoff, maxBackoff, resetDuration time.Duration, backoffFactor, jitter float64, c clock.Clock) BackoffManager {
+	return &exponentialBackoffManagerImpl{
+		backoff: &Backoff{
+			Duration: initBackoff,
+			Factor:   backoffFactor,
+			Jitter:   jitter,
+
+			// the current impl of wait.Backoff returns Backoff.Duration once steps are used up, which is not
+			// what we ideally need here, we set it to max int and assume we will never use up the steps
+			Steps: math.MaxInt32,
+			Cap:   maxBackoff,
+		},
+		backoffTimer:         c.NewTimer(0),
+		initialBackoff:       initBackoff,
+		lastBackoffStart:     c.Now(),
+		backoffResetDuration: resetDuration,
+		clock:                c,
+	}
+}
+
+func (b *exponentialBackoffManagerImpl) getNextBackoff() time.Duration {
+	if b.clock.Now().Sub(b.lastBackoffStart) > b.backoffResetDuration {
+		b.backoff.Steps = math.MaxInt32
+		b.backoff.Duration = b.initialBackoff
+	}
+	b.lastBackoffStart = b.clock.Now()
+	return b.backoff.Step()
+}
+
+// Backoff implements BackoffManager.Backoff, it returns a timer so caller can block on the timer for backoff.
+func (b *exponentialBackoffManagerImpl) Backoff() clock.Timer {
+	b.backoffTimer.Reset(b.getNextBackoff())
+	return b.backoffTimer
+}
+
+type jitteredBackoffManagerImpl struct {
+	clock        clock.Clock
+	duration     time.Duration
+	jitter       float64
+	backoffTimer clock.Timer
+}
+
+// NewJitteredBackoffManager returns a BackoffManager that backoffs with given duration plus given jitter. If the jitter
+// is negative, backoff will not be jittered.
+func NewJitteredBackoffManager(duration time.Duration, jitter float64, c clock.Clock) BackoffManager {
+	return &jitteredBackoffManagerImpl{
+		clock:        c,
+		duration:     duration,
+		jitter:       jitter,
+		backoffTimer: c.NewTimer(0),
+	}
+}
+
+func (j *jitteredBackoffManagerImpl) getNextBackoff() time.Duration {
+	jitteredPeriod := j.duration
+	if j.jitter > 0.0 {
+		jitteredPeriod = Jitter(j.duration, j.jitter)
+	}
+	return jitteredPeriod
+}
+
+func (j *jitteredBackoffManagerImpl) Backoff() clock.Timer {
+	j.backoffTimer.Reset(j.getNextBackoff())
+	return j.backoffTimer
+}
+
 // ExponentialBackoff repeats a condition check with exponential backoff.
 //
 // It repeatedly checks the condition and then sleeps, using `backoff.Step()`
@@ -289,7 +383,7 @@ func contextForChannel(parentCh <-chan struct{}) (context.Context, context.Cance
 // In all other cases, ErrWaitTimeout is returned.
 func ExponentialBackoff(backoff Backoff, condition ConditionFunc) error {
 	for backoff.Steps > 0 {
-		if ok, err := condition(); err != nil || ok {
+		if ok, err := runConditionWithCrashProtection(condition); err != nil || ok {
 			return err
 		}
 		if backoff.Steps == 1 {
@@ -335,7 +429,7 @@ func PollImmediate(interval, timeout time.Duration, condition ConditionFunc) err
 }
 
 func pollImmediateInternal(wait WaitFunc, condition ConditionFunc) error {
-	done, err := condition()
+	done, err := runConditionWithCrashProtection(condition)
 	if err != nil {
 		return err
 	}
@@ -364,7 +458,7 @@ func PollInfinite(interval time.Duration, condition ConditionFunc) error {
 // Some intervals may be missed if the condition takes too long or the time
 // window is too short.
 func PollImmediateInfinite(interval time.Duration, condition ConditionFunc) error {
-	done, err := condition()
+	done, err := runConditionWithCrashProtection(condition)
 	if err != nil {
 		return err
 	}
@@ -431,7 +525,7 @@ func WaitFor(wait WaitFunc, fn ConditionFunc, done <-chan struct{}) error {
 	for {
 		select {
 		case _, open := <-c:
-			ok, err := fn()
+			ok, err := runConditionWithCrashProtection(fn)
 			if err != nil {
 				return err
 			}
@@ -497,16 +591,3 @@ func poller(interval, timeout time.Duration) WaitFunc {
 		return ch
 	})
 }
-
-// resetOrReuseTimer avoids allocating a new timer if one is already in use.
-// Not safe for multiple threads.
-func resetOrReuseTimer(t *time.Timer, d time.Duration, sawTimeout bool) *time.Timer {
-	if t == nil {
-		return time.NewTimer(d)
-	}
-	if !t.Stop() && !sawTimeout {
-		<-t.C
-	}
-	t.Reset(d)
-	return t
-}