Initial QSfera import

Server/vendor/github.com/cenkalti/backoff/.gitignore

@@ -0,0 +1,22 @@
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe

Server/vendor/github.com/cenkalti/backoff/.travis.yml

@@ -0,0 +1,10 @@
+language: go
+go:
+  - 1.7
+  - 1.x
+  - tip
+before_install:
+  - go get github.com/mattn/goveralls
+  - go get golang.org/x/tools/cmd/cover
+script:
+  - $HOME/gopath/bin/goveralls -service=travis-ci

Server/vendor/github.com/cenkalti/backoff/LICENSE

@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Cenk Altı
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Server/vendor/github.com/cenkalti/backoff/README.md

@@ -0,0 +1,30 @@
+# Exponential Backoff [![GoDoc][godoc image]][godoc] [![Build Status][travis image]][travis] [![Coverage Status][coveralls image]][coveralls]
+
+This is a Go port of the exponential backoff algorithm from [Google's HTTP Client Library for Java][google-http-java-client].
+
+[Exponential backoff][exponential backoff wiki]
+is an algorithm that uses feedback to multiplicatively decrease the rate of some process,
+in order to gradually find an acceptable rate.
+The retries exponentially increase and stop increasing when a certain threshold is met.
+
+## Usage
+
+See https://godoc.org/github.com/cenkalti/backoff#pkg-examples
+
+## Contributing
+
+* I would like to keep this library as small as possible.
+* Please don't send a PR without opening an issue and discussing it first.
+* If proposed change is not a common use case, I will probably not accept it.
+
+[godoc]: https://godoc.org/github.com/cenkalti/backoff
+[godoc image]: https://godoc.org/github.com/cenkalti/backoff?status.png
+[travis]: https://travis-ci.org/cenkalti/backoff
+[travis image]: https://travis-ci.org/cenkalti/backoff.png?branch=master
+[coveralls]: https://coveralls.io/github/cenkalti/backoff?branch=master
+[coveralls image]: https://coveralls.io/repos/github/cenkalti/backoff/badge.svg?branch=master
+
+[google-http-java-client]: https://github.com/google/google-http-java-client/blob/da1aa993e90285ec18579f1553339b00e19b3ab5/google-http-client/src/main/java/com/google/api/client/util/ExponentialBackOff.java
+[exponential backoff wiki]: http://en.wikipedia.org/wiki/Exponential_backoff
+
+[advanced example]: https://godoc.org/github.com/cenkalti/backoff#example_

Server/vendor/github.com/cenkalti/backoff/backoff.go

@@ -0,0 +1,66 @@
+// Package backoff implements backoff algorithms for retrying operations.
+//
+// Use Retry function for retrying operations that may fail.
+// If Retry does not meet your needs,
+// copy/paste the function into your project and modify as you wish.
+//
+// There is also Ticker type similar to time.Ticker.
+// You can use it if you need to work with channels.
+//
+// See Examples section below for usage examples.
+package backoff
+
+import "time"
+
+// BackOff is a backoff policy for retrying an operation.
+type BackOff interface {
+	// NextBackOff returns the duration to wait before retrying the operation,
+	// or backoff. Stop to indicate that no more retries should be made.
+	//
+	// Example usage:
+	//
+	// 	duration := backoff.NextBackOff();
+	// 	if (duration == backoff.Stop) {
+	// 		// Do not retry operation.
+	// 	} else {
+	// 		// Sleep for duration and retry operation.
+	// 	}
+	//
+	NextBackOff() time.Duration
+
+	// Reset to initial state.
+	Reset()
+}
+
+// Stop indicates that no more retries should be made for use in NextBackOff().
+const Stop time.Duration = -1
+
+// ZeroBackOff is a fixed backoff policy whose backoff time is always zero,
+// meaning that the operation is retried immediately without waiting, indefinitely.
+type ZeroBackOff struct{}
+
+func (b *ZeroBackOff) Reset() {}
+
+func (b *ZeroBackOff) NextBackOff() time.Duration { return 0 }
+
+// StopBackOff is a fixed backoff policy that always returns backoff.Stop for
+// NextBackOff(), meaning that the operation should never be retried.
+type StopBackOff struct{}
+
+func (b *StopBackOff) Reset() {}
+
+func (b *StopBackOff) NextBackOff() time.Duration { return Stop }
+
+// ConstantBackOff is a backoff policy that always returns the same backoff delay.
+// This is in contrast to an exponential backoff policy,
+// which returns a delay that grows longer as you call NextBackOff() over and over again.
+type ConstantBackOff struct {
+	Interval time.Duration
+}
+
+func (b *ConstantBackOff) Reset()                     {}
+func (b *ConstantBackOff) NextBackOff() time.Duration { return b.Interval }
+
+func NewConstantBackOff(d time.Duration) *ConstantBackOff {
+	return &ConstantBackOff{Interval: d}
+}

Server/vendor/github.com/cenkalti/backoff/context.go

@@ -0,0 +1,63 @@
+package backoff
+
+import (
+	"context"
+	"time"
+)
+
+// BackOffContext is a backoff policy that stops retrying after the context
+// is canceled.
+type BackOffContext interface {
+	BackOff
+	Context() context.Context
+}
+
+type backOffContext struct {
+	BackOff
+	ctx context.Context
+}
+
+// WithContext returns a BackOffContext with context ctx
+//
+// ctx must not be nil
+func WithContext(b BackOff, ctx context.Context) BackOffContext {
+	if ctx == nil {
+		panic("nil context")
+	}
+
+	if b, ok := b.(*backOffContext); ok {
+		return &backOffContext{
+			BackOff: b.BackOff,
+			ctx:     ctx,
+		}
+	}
+
+	return &backOffContext{
+		BackOff: b,
+		ctx:     ctx,
+	}
+}
+
+func ensureContext(b BackOff) BackOffContext {
+	if cb, ok := b.(BackOffContext); ok {
+		return cb
+	}
+	return WithContext(b, context.Background())
+}
+
+func (b *backOffContext) Context() context.Context {
+	return b.ctx
+}
+
+func (b *backOffContext) NextBackOff() time.Duration {
+	select {
+	case <-b.ctx.Done():
+		return Stop
+	default:
+	}
+	next := b.BackOff.NextBackOff()
+	if deadline, ok := b.ctx.Deadline(); ok && deadline.Sub(time.Now()) < next {
+		return Stop
+	}
+	return next
+}

Server/vendor/github.com/cenkalti/backoff/exponential.go

@@ -0,0 +1,153 @@
+package backoff
+
+import (
+	"math/rand"
+	"time"
+)
+
+/*
+ExponentialBackOff is a backoff implementation that increases the backoff
+period for each retry attempt using a randomization function that grows exponentially.
+
+NextBackOff() is calculated using the following formula:
+
+ randomized interval =
+     RetryInterval * (random value in range [1 - RandomizationFactor, 1 + RandomizationFactor])
+
+In other words NextBackOff() will range between the randomization factor
+percentage below and above the retry interval.
+
+For example, given the following parameters:
+
+ RetryInterval = 2
+ RandomizationFactor = 0.5
+ Multiplier = 2
+
+the actual backoff period used in the next retry attempt will range between 1 and 3 seconds,
+multiplied by the exponential, that is, between 2 and 6 seconds.
+
+Note: MaxInterval caps the RetryInterval and not the randomized interval.
+
+If the time elapsed since an ExponentialBackOff instance is created goes past the
+MaxElapsedTime, then the method NextBackOff() starts returning backoff.Stop.
+
+The elapsed time can be reset by calling Reset().
+
+Example: Given the following default arguments, for 10 tries the sequence will be,
+and assuming we go over the MaxElapsedTime on the 10th try:
+
+ Request #  RetryInterval (seconds)  Randomized Interval (seconds)
+
+  1          0.5                     [0.25,   0.75]
+  2          0.75                    [0.375,  1.125]
+  3          1.125                   [0.562,  1.687]
+  4          1.687                   [0.8435, 2.53]
+  5          2.53                    [1.265,  3.795]
+  6          3.795                   [1.897,  5.692]
+  7          5.692                   [2.846,  8.538]
+  8          8.538                   [4.269, 12.807]
+  9         12.807                   [6.403, 19.210]
+ 10         19.210                   backoff.Stop
+
+Note: Implementation is not thread-safe.
+*/
+type ExponentialBackOff struct {
+	InitialInterval     time.Duration
+	RandomizationFactor float64
+	Multiplier          float64
+	MaxInterval         time.Duration
+	// After MaxElapsedTime the ExponentialBackOff stops.
+	// It never stops if MaxElapsedTime == 0.
+	MaxElapsedTime time.Duration
+	Clock          Clock
+
+	currentInterval time.Duration
+	startTime       time.Time
+}
+
+// Clock is an interface that returns current time for BackOff.
+type Clock interface {
+	Now() time.Time
+}
+
+// Default values for ExponentialBackOff.
+const (
+	DefaultInitialInterval     = 500 * time.Millisecond
+	DefaultRandomizationFactor = 0.5
+	DefaultMultiplier          = 1.5
+	DefaultMaxInterval         = 60 * time.Second
+	DefaultMaxElapsedTime      = 15 * time.Minute
+)
+
+// NewExponentialBackOff creates an instance of ExponentialBackOff using default values.
+func NewExponentialBackOff() *ExponentialBackOff {
+	b := &ExponentialBackOff{
+		InitialInterval:     DefaultInitialInterval,
+		RandomizationFactor: DefaultRandomizationFactor,
+		Multiplier:          DefaultMultiplier,
+		MaxInterval:         DefaultMaxInterval,
+		MaxElapsedTime:      DefaultMaxElapsedTime,
+		Clock:               SystemClock,
+	}
+	b.Reset()
+	return b
+}
+
+type systemClock struct{}
+
+func (t systemClock) Now() time.Time {
+	return time.Now()
+}
+
+// SystemClock implements Clock interface that uses time.Now().
+var SystemClock = systemClock{}
+
+// Reset the interval back to the initial retry interval and restarts the timer.
+func (b *ExponentialBackOff) Reset() {
+	b.currentInterval = b.InitialInterval
+	b.startTime = b.Clock.Now()
+}
+
+// NextBackOff calculates the next backoff interval using the formula:
+// 	Randomized interval = RetryInterval +/- (RandomizationFactor * RetryInterval)
+func (b *ExponentialBackOff) NextBackOff() time.Duration {
+	// Make sure we have not gone over the maximum elapsed time.
+	if b.MaxElapsedTime != 0 && b.GetElapsedTime() > b.MaxElapsedTime {
+		return Stop
+	}
+	defer b.incrementCurrentInterval()
+	return getRandomValueFromInterval(b.RandomizationFactor, rand.Float64(), b.currentInterval)
+}
+
+// GetElapsedTime returns the elapsed time since an ExponentialBackOff instance
+// is created and is reset when Reset() is called.
+//
+// The elapsed time is computed using time.Now().UnixNano(). It is
+// safe to call even while the backoff policy is used by a running
+// ticker.
+func (b *ExponentialBackOff) GetElapsedTime() time.Duration {
+	return b.Clock.Now().Sub(b.startTime)
+}
+
+// Increments the current interval by multiplying it with the multiplier.
+func (b *ExponentialBackOff) incrementCurrentInterval() {
+	// Check for overflow, if overflow is detected set the current interval to the max interval.
+	if float64(b.currentInterval) >= float64(b.MaxInterval)/b.Multiplier {
+		b.currentInterval = b.MaxInterval
+	} else {
+		b.currentInterval = time.Duration(float64(b.currentInterval) * b.Multiplier)
+	}
+}
+
+// Returns a random value from the following interval:
+// 	[randomizationFactor * currentInterval, randomizationFactor * currentInterval].
+func getRandomValueFromInterval(randomizationFactor, random float64, currentInterval time.Duration) time.Duration {
+	var delta = randomizationFactor * float64(currentInterval)
+	var minInterval = float64(currentInterval) - delta
+	var maxInterval = float64(currentInterval) + delta
+
+	// Get a random value from the range [minInterval, maxInterval].
+	// The formula used below has a +1 because if the minInterval is 1 and the maxInterval is 3 then
+	// we want a 33% chance for selecting either 1, 2 or 3.
+	return time.Duration(minInterval + (random * (maxInterval - minInterval + 1)))
+}

Server/vendor/github.com/cenkalti/backoff/retry.go

@@ -0,0 +1,82 @@
+package backoff
+
+import "time"
+
+// An Operation is executing by Retry() or RetryNotify().
+// The operation will be retried using a backoff policy if it returns an error.
+type Operation func() error
+
+// Notify is a notify-on-error function. It receives an operation error and
+// backoff delay if the operation failed (with an error).
+//
+// NOTE that if the backoff policy stated to stop retrying,
+// the notify function isn't called.
+type Notify func(error, time.Duration)
+
+// Retry the operation o until it does not return error or BackOff stops.
+// o is guaranteed to be run at least once.
+//
+// If o returns a *PermanentError, the operation is not retried, and the
+// wrapped error is returned.
+//
+// Retry sleeps the goroutine for the duration returned by BackOff after a
+// failed operation returns.
+func Retry(o Operation, b BackOff) error { return RetryNotify(o, b, nil) }
+
+// RetryNotify calls notify function with the error and wait duration
+// for each failed attempt before sleep.
+func RetryNotify(operation Operation, b BackOff, notify Notify) error {
+	var err error
+	var next time.Duration
+	var t *time.Timer
+
+	cb := ensureContext(b)
+
+	b.Reset()
+	for {
+		if err = operation(); err == nil {
+			return nil
+		}
+
+		if permanent, ok := err.(*PermanentError); ok {
+			return permanent.Err
+		}
+
+		if next = cb.NextBackOff(); next == Stop {
+			return err
+		}
+
+		if notify != nil {
+			notify(err, next)
+		}
+
+		if t == nil {
+			t = time.NewTimer(next)
+			defer t.Stop()
+		} else {
+			t.Reset(next)
+		}
+
+		select {
+		case <-cb.Context().Done():
+			return err
+		case <-t.C:
+		}
+	}
+}
+
+// PermanentError signals that the operation should not be retried.
+type PermanentError struct {
+	Err error
+}
+
+func (e *PermanentError) Error() string {
+	return e.Err.Error()
+}
+
+// Permanent wraps the given err in a *PermanentError.
+func Permanent(err error) *PermanentError {
+	return &PermanentError{
+		Err: err,
+	}
+}

Server/vendor/github.com/cenkalti/backoff/ticker.go

@@ -0,0 +1,82 @@
+package backoff
+
+import (
+	"sync"
+	"time"
+)
+
+// Ticker holds a channel that delivers `ticks' of a clock at times reported by a BackOff.
+//
+// Ticks will continue to arrive when the previous operation is still running,
+// so operations that take a while to fail could run in quick succession.
+type Ticker struct {
+	C        <-chan time.Time
+	c        chan time.Time
+	b        BackOffContext
+	stop     chan struct{}
+	stopOnce sync.Once
+}
+
+// NewTicker returns a new Ticker containing a channel that will send
+// the time at times specified by the BackOff argument. Ticker is
+// guaranteed to tick at least once.  The channel is closed when Stop
+// method is called or BackOff stops. It is not safe to manipulate the
+// provided backoff policy (notably calling NextBackOff or Reset)
+// while the ticker is running.
+func NewTicker(b BackOff) *Ticker {
+	c := make(chan time.Time)
+	t := &Ticker{
+		C:    c,
+		c:    c,
+		b:    ensureContext(b),
+		stop: make(chan struct{}),
+	}
+	t.b.Reset()
+	go t.run()
+	return t
+}
+
+// Stop turns off a ticker. After Stop, no more ticks will be sent.
+func (t *Ticker) Stop() {
+	t.stopOnce.Do(func() { close(t.stop) })
+}
+
+func (t *Ticker) run() {
+	c := t.c
+	defer close(c)
+
+	// Ticker is guaranteed to tick at least once.
+	afterC := t.send(time.Now())
+
+	for {
+		if afterC == nil {
+			return
+		}
+
+		select {
+		case tick := <-afterC:
+			afterC = t.send(tick)
+		case <-t.stop:
+			t.c = nil // Prevent future ticks from being sent to the channel.
+			return
+		case <-t.b.Context().Done():
+			return
+		}
+	}
+}
+
+func (t *Ticker) send(tick time.Time) <-chan time.Time {
+	select {
+	case t.c <- tick:
+	case <-t.stop:
+		return nil
+	}
+
+	next := t.b.NextBackOff()
+	if next == Stop {
+		t.Stop()
+		return nil
+	}
+
+	return time.After(next)
+}

Server/vendor/github.com/cenkalti/backoff/tries.go

@@ -0,0 +1,35 @@
+package backoff
+
+import "time"
+
+/*
+WithMaxRetries creates a wrapper around another BackOff, which will
+return Stop if NextBackOff() has been called too many times since
+the last time Reset() was called
+
+Note: Implementation is not thread-safe.
+*/
+func WithMaxRetries(b BackOff, max uint64) BackOff {
+	return &backOffTries{delegate: b, maxTries: max}
+}
+
+type backOffTries struct {
+	delegate BackOff
+	maxTries uint64
+	numTries uint64
+}
+
+func (b *backOffTries) NextBackOff() time.Duration {
+	if b.maxTries > 0 {
+		if b.maxTries <= b.numTries {
+			return Stop
+		}
+		b.numTries++
+	}
+	return b.delegate.NextBackOff()
+}
+
+func (b *backOffTries) Reset() {
+	b.numTries = 0
+	b.delegate.Reset()
+}

Server/vendor/github.com/cenkalti/backoff/v4/.gitignore

@@ -0,0 +1,25 @@
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+
+# IDEs
+.idea/

Server/vendor/github.com/cenkalti/backoff/v4/LICENSE

@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Cenk Altı
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Server/vendor/github.com/cenkalti/backoff/v4/README.md

@@ -0,0 +1,30 @@
+# Exponential Backoff [![GoDoc][godoc image]][godoc] [![Coverage Status][coveralls image]][coveralls]
+
+This is a Go port of the exponential backoff algorithm from [Google's HTTP Client Library for Java][google-http-java-client].
+
+[Exponential backoff][exponential backoff wiki]
+is an algorithm that uses feedback to multiplicatively decrease the rate of some process,
+in order to gradually find an acceptable rate.
+The retries exponentially increase and stop increasing when a certain threshold is met.
+
+## Usage
+
+Import path is `github.com/cenkalti/backoff/v4`. Please note the version part at the end.
+
+Use https://pkg.go.dev/github.com/cenkalti/backoff/v4 to view the documentation.
+
+## Contributing
+
+* I would like to keep this library as small as possible.
+* Please don't send a PR without opening an issue and discussing it first.
+* If proposed change is not a common use case, I will probably not accept it.
+
+[godoc]: https://pkg.go.dev/github.com/cenkalti/backoff/v4
+[godoc image]: https://godoc.org/github.com/cenkalti/backoff?status.png
+[coveralls]: https://coveralls.io/github/cenkalti/backoff?branch=master
+[coveralls image]: https://coveralls.io/repos/github/cenkalti/backoff/badge.svg?branch=master
+
+[google-http-java-client]: https://github.com/google/google-http-java-client/blob/da1aa993e90285ec18579f1553339b00e19b3ab5/google-http-client/src/main/java/com/google/api/client/util/ExponentialBackOff.java
+[exponential backoff wiki]: http://en.wikipedia.org/wiki/Exponential_backoff
+
+[advanced example]: https://pkg.go.dev/github.com/cenkalti/backoff/v4?tab=doc#pkg-examples

Server/vendor/github.com/cenkalti/backoff/v4/backoff.go

@@ -0,0 +1,66 @@
+// Package backoff implements backoff algorithms for retrying operations.
+//
+// Use Retry function for retrying operations that may fail.
+// If Retry does not meet your needs,
+// copy/paste the function into your project and modify as you wish.
+//
+// There is also Ticker type similar to time.Ticker.
+// You can use it if you need to work with channels.
+//
+// See Examples section below for usage examples.
+package backoff
+
+import "time"
+
+// BackOff is a backoff policy for retrying an operation.
+type BackOff interface {
+	// NextBackOff returns the duration to wait before retrying the operation,
+	// or backoff. Stop to indicate that no more retries should be made.
+	//
+	// Example usage:
+	//
+	// 	duration := backoff.NextBackOff();
+	// 	if (duration == backoff.Stop) {
+	// 		// Do not retry operation.
+	// 	} else {
+	// 		// Sleep for duration and retry operation.
+	// 	}
+	//
+	NextBackOff() time.Duration
+
+	// Reset to initial state.
+	Reset()
+}
+
+// Stop indicates that no more retries should be made for use in NextBackOff().
+const Stop time.Duration = -1
+
+// ZeroBackOff is a fixed backoff policy whose backoff time is always zero,
+// meaning that the operation is retried immediately without waiting, indefinitely.
+type ZeroBackOff struct{}
+
+func (b *ZeroBackOff) Reset() {}
+
+func (b *ZeroBackOff) NextBackOff() time.Duration { return 0 }
+
+// StopBackOff is a fixed backoff policy that always returns backoff.Stop for
+// NextBackOff(), meaning that the operation should never be retried.
+type StopBackOff struct{}
+
+func (b *StopBackOff) Reset() {}
+
+func (b *StopBackOff) NextBackOff() time.Duration { return Stop }
+
+// ConstantBackOff is a backoff policy that always returns the same backoff delay.
+// This is in contrast to an exponential backoff policy,
+// which returns a delay that grows longer as you call NextBackOff() over and over again.
+type ConstantBackOff struct {
+	Interval time.Duration
+}
+
+func (b *ConstantBackOff) Reset()                     {}
+func (b *ConstantBackOff) NextBackOff() time.Duration { return b.Interval }
+
+func NewConstantBackOff(d time.Duration) *ConstantBackOff {
+	return &ConstantBackOff{Interval: d}
+}

Server/vendor/github.com/cenkalti/backoff/v4/context.go

@@ -0,0 +1,62 @@
+package backoff
+
+import (
+	"context"
+	"time"
+)
+
+// BackOffContext is a backoff policy that stops retrying after the context
+// is canceled.
+type BackOffContext interface { // nolint: golint
+	BackOff
+	Context() context.Context
+}
+
+type backOffContext struct {
+	BackOff
+	ctx context.Context
+}
+
+// WithContext returns a BackOffContext with context ctx
+//
+// ctx must not be nil
+func WithContext(b BackOff, ctx context.Context) BackOffContext { // nolint: golint
+	if ctx == nil {
+		panic("nil context")
+	}
+
+	if b, ok := b.(*backOffContext); ok {
+		return &backOffContext{
+			BackOff: b.BackOff,
+			ctx:     ctx,
+		}
+	}
+
+	return &backOffContext{
+		BackOff: b,
+		ctx:     ctx,
+	}
+}
+
+func getContext(b BackOff) context.Context {
+	if cb, ok := b.(BackOffContext); ok {
+		return cb.Context()
+	}
+	if tb, ok := b.(*backOffTries); ok {
+		return getContext(tb.delegate)
+	}
+	return context.Background()
+}
+
+func (b *backOffContext) Context() context.Context {
+	return b.ctx
+}
+
+func (b *backOffContext) NextBackOff() time.Duration {
+	select {
+	case <-b.ctx.Done():
+		return Stop
+	default:
+		return b.BackOff.NextBackOff()
+	}
+}

Server/vendor/github.com/cenkalti/backoff/v4/exponential.go

@@ -0,0 +1,216 @@
+package backoff
+
+import (
+	"math/rand"
+	"time"
+)
+
+/*
+ExponentialBackOff is a backoff implementation that increases the backoff
+period for each retry attempt using a randomization function that grows exponentially.
+
+NextBackOff() is calculated using the following formula:
+
+ randomized interval =
+     RetryInterval * (random value in range [1 - RandomizationFactor, 1 + RandomizationFactor])
+
+In other words NextBackOff() will range between the randomization factor
+percentage below and above the retry interval.
+
+For example, given the following parameters:
+
+ RetryInterval = 2
+ RandomizationFactor = 0.5
+ Multiplier = 2
+
+the actual backoff period used in the next retry attempt will range between 1 and 3 seconds,
+multiplied by the exponential, that is, between 2 and 6 seconds.
+
+Note: MaxInterval caps the RetryInterval and not the randomized interval.
+
+If the time elapsed since an ExponentialBackOff instance is created goes past the
+MaxElapsedTime, then the method NextBackOff() starts returning backoff.Stop.
+
+The elapsed time can be reset by calling Reset().
+
+Example: Given the following default arguments, for 10 tries the sequence will be,
+and assuming we go over the MaxElapsedTime on the 10th try:
+
+ Request #  RetryInterval (seconds)  Randomized Interval (seconds)
+
+  1          0.5                     [0.25,   0.75]
+  2          0.75                    [0.375,  1.125]
+  3          1.125                   [0.562,  1.687]
+  4          1.687                   [0.8435, 2.53]
+  5          2.53                    [1.265,  3.795]
+  6          3.795                   [1.897,  5.692]
+  7          5.692                   [2.846,  8.538]
+  8          8.538                   [4.269, 12.807]
+  9         12.807                   [6.403, 19.210]
+ 10         19.210                   backoff.Stop
+
+Note: Implementation is not thread-safe.
+*/
+type ExponentialBackOff struct {
+	InitialInterval     time.Duration
+	RandomizationFactor float64
+	Multiplier          float64
+	MaxInterval         time.Duration
+	// After MaxElapsedTime the ExponentialBackOff returns Stop.
+	// It never stops if MaxElapsedTime == 0.
+	MaxElapsedTime time.Duration
+	Stop           time.Duration
+	Clock          Clock
+
+	currentInterval time.Duration
+	startTime       time.Time
+}
+
+// Clock is an interface that returns current time for BackOff.
+type Clock interface {
+	Now() time.Time
+}
+
+// ExponentialBackOffOpts is a function type used to configure ExponentialBackOff options.
+type ExponentialBackOffOpts func(*ExponentialBackOff)
+
+// Default values for ExponentialBackOff.
+const (
+	DefaultInitialInterval     = 500 * time.Millisecond
+	DefaultRandomizationFactor = 0.5
+	DefaultMultiplier          = 1.5
+	DefaultMaxInterval         = 60 * time.Second
+	DefaultMaxElapsedTime      = 15 * time.Minute
+)
+
+// NewExponentialBackOff creates an instance of ExponentialBackOff using default values.
+func NewExponentialBackOff(opts ...ExponentialBackOffOpts) *ExponentialBackOff {
+	b := &ExponentialBackOff{
+		InitialInterval:     DefaultInitialInterval,
+		RandomizationFactor: DefaultRandomizationFactor,
+		Multiplier:          DefaultMultiplier,
+		MaxInterval:         DefaultMaxInterval,
+		MaxElapsedTime:      DefaultMaxElapsedTime,
+		Stop:                Stop,
+		Clock:               SystemClock,
+	}
+	for _, fn := range opts {
+		fn(b)
+	}
+	b.Reset()
+	return b
+}
+
+// WithInitialInterval sets the initial interval between retries.
+func WithInitialInterval(duration time.Duration) ExponentialBackOffOpts {
+	return func(ebo *ExponentialBackOff) {
+		ebo.InitialInterval = duration
+	}
+}
+
+// WithRandomizationFactor sets the randomization factor to add jitter to intervals.
+func WithRandomizationFactor(randomizationFactor float64) ExponentialBackOffOpts {
+	return func(ebo *ExponentialBackOff) {
+		ebo.RandomizationFactor = randomizationFactor
+	}
+}
+
+// WithMultiplier sets the multiplier for increasing the interval after each retry.
+func WithMultiplier(multiplier float64) ExponentialBackOffOpts {
+	return func(ebo *ExponentialBackOff) {
+		ebo.Multiplier = multiplier
+	}
+}
+
+// WithMaxInterval sets the maximum interval between retries.
+func WithMaxInterval(duration time.Duration) ExponentialBackOffOpts {
+	return func(ebo *ExponentialBackOff) {
+		ebo.MaxInterval = duration
+	}
+}
+
+// WithMaxElapsedTime sets the maximum total time for retries.
+func WithMaxElapsedTime(duration time.Duration) ExponentialBackOffOpts {
+	return func(ebo *ExponentialBackOff) {
+		ebo.MaxElapsedTime = duration
+	}
+}
+
+// WithRetryStopDuration sets the duration after which retries should stop.
+func WithRetryStopDuration(duration time.Duration) ExponentialBackOffOpts {
+	return func(ebo *ExponentialBackOff) {
+		ebo.Stop = duration
+	}
+}
+
+// WithClockProvider sets the clock used to measure time.
+func WithClockProvider(clock Clock) ExponentialBackOffOpts {
+	return func(ebo *ExponentialBackOff) {
+		ebo.Clock = clock
+	}
+}
+
+type systemClock struct{}
+
+func (t systemClock) Now() time.Time {
+	return time.Now()
+}
+
+// SystemClock implements Clock interface that uses time.Now().
+var SystemClock = systemClock{}
+
+// Reset the interval back to the initial retry interval and restarts the timer.
+// Reset must be called before using b.
+func (b *ExponentialBackOff) Reset() {
+	b.currentInterval = b.InitialInterval
+	b.startTime = b.Clock.Now()
+}
+
+// NextBackOff calculates the next backoff interval using the formula:
+// 	Randomized interval = RetryInterval * (1 ± RandomizationFactor)
+func (b *ExponentialBackOff) NextBackOff() time.Duration {
+	// Make sure we have not gone over the maximum elapsed time.
+	elapsed := b.GetElapsedTime()
+	next := getRandomValueFromInterval(b.RandomizationFactor, rand.Float64(), b.currentInterval)
+	b.incrementCurrentInterval()
+	if b.MaxElapsedTime != 0 && elapsed+next > b.MaxElapsedTime {
+		return b.Stop
+	}
+	return next
+}
+
+// GetElapsedTime returns the elapsed time since an ExponentialBackOff instance
+// is created and is reset when Reset() is called.
+//
+// The elapsed time is computed using time.Now().UnixNano(). It is
+// safe to call even while the backoff policy is used by a running
+// ticker.
+func (b *ExponentialBackOff) GetElapsedTime() time.Duration {
+	return b.Clock.Now().Sub(b.startTime)
+}
+
+// Increments the current interval by multiplying it with the multiplier.
+func (b *ExponentialBackOff) incrementCurrentInterval() {
+	// Check for overflow, if overflow is detected set the current interval to the max interval.
+	if float64(b.currentInterval) >= float64(b.MaxInterval)/b.Multiplier {
+		b.currentInterval = b.MaxInterval
+	} else {
+		b.currentInterval = time.Duration(float64(b.currentInterval) * b.Multiplier)
+	}
+}
+
+// Returns a random value from the following interval:
+// 	[currentInterval - randomizationFactor * currentInterval, currentInterval + randomizationFactor * currentInterval].
+func getRandomValueFromInterval(randomizationFactor, random float64, currentInterval time.Duration) time.Duration {
+	if randomizationFactor == 0 {
+		return currentInterval // make sure no randomness is used when randomizationFactor is 0.
+	}
+	var delta = randomizationFactor * float64(currentInterval)
+	var minInterval = float64(currentInterval) - delta
+	var maxInterval = float64(currentInterval) + delta
+
+	// Get a random value from the range [minInterval, maxInterval].
+	// The formula used below has a +1 because if the minInterval is 1 and the maxInterval is 3 then
+	// we want a 33% chance for selecting either 1, 2 or 3.
+	return time.Duration(minInterval + (random * (maxInterval - minInterval + 1)))
+}

Server/vendor/github.com/cenkalti/backoff/v4/retry.go

@@ -0,0 +1,146 @@
+package backoff
+
+import (
+	"errors"
+	"time"
+)
+
+// An OperationWithData is executing by RetryWithData() or RetryNotifyWithData().
+// The operation will be retried using a backoff policy if it returns an error.
+type OperationWithData[T any] func() (T, error)
+
+// An Operation is executing by Retry() or RetryNotify().
+// The operation will be retried using a backoff policy if it returns an error.
+type Operation func() error
+
+func (o Operation) withEmptyData() OperationWithData[struct{}] {
+	return func() (struct{}, error) {
+		return struct{}{}, o()
+	}
+}
+
+// Notify is a notify-on-error function. It receives an operation error and
+// backoff delay if the operation failed (with an error).
+//
+// NOTE that if the backoff policy stated to stop retrying,
+// the notify function isn't called.
+type Notify func(error, time.Duration)
+
+// Retry the operation o until it does not return error or BackOff stops.
+// o is guaranteed to be run at least once.
+//
+// If o returns a *PermanentError, the operation is not retried, and the
+// wrapped error is returned.
+//
+// Retry sleeps the goroutine for the duration returned by BackOff after a
+// failed operation returns.
+func Retry(o Operation, b BackOff) error {
+	return RetryNotify(o, b, nil)
+}
+
+// RetryWithData is like Retry but returns data in the response too.
+func RetryWithData[T any](o OperationWithData[T], b BackOff) (T, error) {
+	return RetryNotifyWithData(o, b, nil)
+}
+
+// RetryNotify calls notify function with the error and wait duration
+// for each failed attempt before sleep.
+func RetryNotify(operation Operation, b BackOff, notify Notify) error {
+	return RetryNotifyWithTimer(operation, b, notify, nil)
+}
+
+// RetryNotifyWithData is like RetryNotify but returns data in the response too.
+func RetryNotifyWithData[T any](operation OperationWithData[T], b BackOff, notify Notify) (T, error) {
+	return doRetryNotify(operation, b, notify, nil)
+}
+
+// RetryNotifyWithTimer calls notify function with the error and wait duration using the given Timer
+// for each failed attempt before sleep.
+// A default timer that uses system timer is used when nil is passed.
+func RetryNotifyWithTimer(operation Operation, b BackOff, notify Notify, t Timer) error {
+	_, err := doRetryNotify(operation.withEmptyData(), b, notify, t)
+	return err
+}
+
+// RetryNotifyWithTimerAndData is like RetryNotifyWithTimer but returns data in the response too.
+func RetryNotifyWithTimerAndData[T any](operation OperationWithData[T], b BackOff, notify Notify, t Timer) (T, error) {
+	return doRetryNotify(operation, b, notify, t)
+}
+
+func doRetryNotify[T any](operation OperationWithData[T], b BackOff, notify Notify, t Timer) (T, error) {
+	var (
+		err  error
+		next time.Duration
+		res  T
+	)
+	if t == nil {
+		t = &defaultTimer{}
+	}
+
+	defer func() {
+		t.Stop()
+	}()
+
+	ctx := getContext(b)
+
+	b.Reset()
+	for {
+		res, err = operation()
+		if err == nil {
+			return res, nil
+		}
+
+		var permanent *PermanentError
+		if errors.As(err, &permanent) {
+			return res, permanent.Err
+		}
+
+		if next = b.NextBackOff(); next == Stop {
+			if cerr := ctx.Err(); cerr != nil {
+				return res, cerr
+			}
+
+			return res, err
+		}
+
+		if notify != nil {
+			notify(err, next)
+		}
+
+		t.Start(next)
+
+		select {
+		case <-ctx.Done():
+			return res, ctx.Err()
+		case <-t.C():
+		}
+	}
+}
+
+// PermanentError signals that the operation should not be retried.
+type PermanentError struct {
+	Err error
+}
+
+func (e *PermanentError) Error() string {
+	return e.Err.Error()
+}
+
+func (e *PermanentError) Unwrap() error {
+	return e.Err
+}
+
+func (e *PermanentError) Is(target error) bool {
+	_, ok := target.(*PermanentError)
+	return ok
+}
+
+// Permanent wraps the given err in a *PermanentError.
+func Permanent(err error) error {
+	if err == nil {
+		return nil
+	}
+	return &PermanentError{
+		Err: err,
+	}
+}

Server/vendor/github.com/cenkalti/backoff/v4/ticker.go

@@ -0,0 +1,97 @@
+package backoff
+
+import (
+	"context"
+	"sync"
+	"time"
+)
+
+// Ticker holds a channel that delivers `ticks' of a clock at times reported by a BackOff.
+//
+// Ticks will continue to arrive when the previous operation is still running,
+// so operations that take a while to fail could run in quick succession.
+type Ticker struct {
+	C        <-chan time.Time
+	c        chan time.Time
+	b        BackOff
+	ctx      context.Context
+	timer    Timer
+	stop     chan struct{}
+	stopOnce sync.Once
+}
+
+// NewTicker returns a new Ticker containing a channel that will send
+// the time at times specified by the BackOff argument. Ticker is
+// guaranteed to tick at least once.  The channel is closed when Stop
+// method is called or BackOff stops. It is not safe to manipulate the
+// provided backoff policy (notably calling NextBackOff or Reset)
+// while the ticker is running.
+func NewTicker(b BackOff) *Ticker {
+	return NewTickerWithTimer(b, &defaultTimer{})
+}
+
+// NewTickerWithTimer returns a new Ticker with a custom timer.
+// A default timer that uses system timer is used when nil is passed.
+func NewTickerWithTimer(b BackOff, timer Timer) *Ticker {
+	if timer == nil {
+		timer = &defaultTimer{}
+	}
+	c := make(chan time.Time)
+	t := &Ticker{
+		C:     c,
+		c:     c,
+		b:     b,
+		ctx:   getContext(b),
+		timer: timer,
+		stop:  make(chan struct{}),
+	}
+	t.b.Reset()
+	go t.run()
+	return t
+}
+
+// Stop turns off a ticker. After Stop, no more ticks will be sent.
+func (t *Ticker) Stop() {
+	t.stopOnce.Do(func() { close(t.stop) })
+}
+
+func (t *Ticker) run() {
+	c := t.c
+	defer close(c)
+
+	// Ticker is guaranteed to tick at least once.
+	afterC := t.send(time.Now())
+
+	for {
+		if afterC == nil {
+			return
+		}
+
+		select {
+		case tick := <-afterC:
+			afterC = t.send(tick)
+		case <-t.stop:
+			t.c = nil // Prevent future ticks from being sent to the channel.
+			return
+		case <-t.ctx.Done():
+			return
+		}
+	}
+}
+
+func (t *Ticker) send(tick time.Time) <-chan time.Time {
+	select {
+	case t.c <- tick:
+	case <-t.stop:
+		return nil
+	}
+
+	next := t.b.NextBackOff()
+	if next == Stop {
+		t.Stop()
+		return nil
+	}
+
+	t.timer.Start(next)
+	return t.timer.C()
+}

Server/vendor/github.com/cenkalti/backoff/v4/timer.go

@@ -0,0 +1,35 @@
+package backoff
+
+import "time"
+
+type Timer interface {
+	Start(duration time.Duration)
+	Stop()
+	C() <-chan time.Time
+}
+
+// defaultTimer implements Timer interface using time.Timer
+type defaultTimer struct {
+	timer *time.Timer
+}
+
+// C returns the timers channel which receives the current time when the timer fires.
+func (t *defaultTimer) C() <-chan time.Time {
+	return t.timer.C
+}
+
+// Start starts the timer to fire after the given duration
+func (t *defaultTimer) Start(duration time.Duration) {
+	if t.timer == nil {
+		t.timer = time.NewTimer(duration)
+	} else {
+		t.timer.Reset(duration)
+	}
+}
+
+// Stop is called when the timer is not used anymore and resources may be freed.
+func (t *defaultTimer) Stop() {
+	if t.timer != nil {
+		t.timer.Stop()
+	}
+}

Server/vendor/github.com/cenkalti/backoff/v4/tries.go

@@ -0,0 +1,38 @@
+package backoff
+
+import "time"
+
+/*
+WithMaxRetries creates a wrapper around another BackOff, which will
+return Stop if NextBackOff() has been called too many times since
+the last time Reset() was called
+
+Note: Implementation is not thread-safe.
+*/
+func WithMaxRetries(b BackOff, max uint64) BackOff {
+	return &backOffTries{delegate: b, maxTries: max}
+}
+
+type backOffTries struct {
+	delegate BackOff
+	maxTries uint64
+	numTries uint64
+}
+
+func (b *backOffTries) NextBackOff() time.Duration {
+	if b.maxTries == 0 {
+		return Stop
+	}
+	if b.maxTries > 0 {
+		if b.maxTries <= b.numTries {
+			return Stop
+		}
+		b.numTries++
+	}
+	return b.delegate.NextBackOff()
+}
+
+func (b *backOffTries) Reset() {
+	b.numTries = 0
+	b.delegate.Reset()
+}

Server/vendor/github.com/cenkalti/backoff/v5/.gitignore

@@ -0,0 +1,25 @@
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+
+# IDEs
+.idea/

Server/vendor/github.com/cenkalti/backoff/v5/CHANGELOG.md

@@ -0,0 +1,29 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [5.0.0] - 2024-12-19
+
+### Added
+
+- RetryAfterError can be returned from an operation to indicate how long to wait before the next retry.
+
+### Changed
+
+- Retry function now accepts additional options for specifying max number of tries and max elapsed time.
+- Retry function now accepts a context.Context.
+- Operation function signature changed to return result (any type) and error.
+
+### Removed
+
+- RetryNotify* and RetryWithData functions. Only single Retry function remains.
+- Optional arguments from ExponentialBackoff constructor.
+- Clock and Timer interfaces.
+
+### Fixed
+
+- The original error is returned from Retry if there's a PermanentError. (#144)
+- The Retry function respects the wrapped PermanentError. (#140)

Server/vendor/github.com/cenkalti/backoff/v5/LICENSE

@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Cenk Altı
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Server/vendor/github.com/cenkalti/backoff/v5/README.md

@@ -0,0 +1,31 @@
+# Exponential Backoff [![GoDoc][godoc image]][godoc]
+
+This is a Go port of the exponential backoff algorithm from [Google's HTTP Client Library for Java][google-http-java-client].
+
+[Exponential backoff][exponential backoff wiki]
+is an algorithm that uses feedback to multiplicatively decrease the rate of some process,
+in order to gradually find an acceptable rate.
+The retries exponentially increase and stop increasing when a certain threshold is met.
+
+## Usage
+
+Import path is `github.com/cenkalti/backoff/v5`. Please note the version part at the end.
+
+For most cases, use `Retry` function. See [example_test.go][example] for an example.
+
+If you have specific needs, copy `Retry` function (from [retry.go][retry-src]) into your code and modify it as needed.
+
+## Contributing
+
+* I would like to keep this library as small as possible.
+* Please don't send a PR without opening an issue and discussing it first.
+* If proposed change is not a common use case, I will probably not accept it.
+
+[godoc]: https://pkg.go.dev/github.com/cenkalti/backoff/v5
+[godoc image]: https://godoc.org/github.com/cenkalti/backoff?status.png
+
+[google-http-java-client]: https://github.com/google/google-http-java-client/blob/da1aa993e90285ec18579f1553339b00e19b3ab5/google-http-client/src/main/java/com/google/api/client/util/ExponentialBackOff.java
+[exponential backoff wiki]: http://en.wikipedia.org/wiki/Exponential_backoff
+
+[retry-src]: https://github.com/cenkalti/backoff/blob/v5/retry.go
+[example]: https://github.com/cenkalti/backoff/blob/v5/example_test.go

Server/vendor/github.com/cenkalti/backoff/v5/backoff.go

@@ -0,0 +1,66 @@
+// Package backoff implements backoff algorithms for retrying operations.
+//
+// Use Retry function for retrying operations that may fail.
+// If Retry does not meet your needs,
+// copy/paste the function into your project and modify as you wish.
+//
+// There is also Ticker type similar to time.Ticker.
+// You can use it if you need to work with channels.
+//
+// See Examples section below for usage examples.
+package backoff
+
+import "time"
+
+// BackOff is a backoff policy for retrying an operation.
+type BackOff interface {
+	// NextBackOff returns the duration to wait before retrying the operation,
+	// backoff.Stop to indicate that no more retries should be made.
+	//
+	// Example usage:
+	//
+	//     duration := backoff.NextBackOff()
+	//     if duration == backoff.Stop {
+	//         // Do not retry operation.
+	//     } else {
+	//         // Sleep for duration and retry operation.
+	//     }
+	//
+	NextBackOff() time.Duration
+
+	// Reset to initial state.
+	Reset()
+}
+
+// Stop indicates that no more retries should be made for use in NextBackOff().
+const Stop time.Duration = -1
+
+// ZeroBackOff is a fixed backoff policy whose backoff time is always zero,
+// meaning that the operation is retried immediately without waiting, indefinitely.
+type ZeroBackOff struct{}
+
+func (b *ZeroBackOff) Reset() {}
+
+func (b *ZeroBackOff) NextBackOff() time.Duration { return 0 }
+
+// StopBackOff is a fixed backoff policy that always returns backoff.Stop for
+// NextBackOff(), meaning that the operation should never be retried.
+type StopBackOff struct{}
+
+func (b *StopBackOff) Reset() {}
+
+func (b *StopBackOff) NextBackOff() time.Duration { return Stop }
+
+// ConstantBackOff is a backoff policy that always returns the same backoff delay.
+// This is in contrast to an exponential backoff policy,
+// which returns a delay that grows longer as you call NextBackOff() over and over again.
+type ConstantBackOff struct {
+	Interval time.Duration
+}
+
+func (b *ConstantBackOff) Reset()                     {}
+func (b *ConstantBackOff) NextBackOff() time.Duration { return b.Interval }
+
+func NewConstantBackOff(d time.Duration) *ConstantBackOff {
+	return &ConstantBackOff{Interval: d}
+}

Server/vendor/github.com/cenkalti/backoff/v5/error.go

@@ -0,0 +1,46 @@
+package backoff
+
+import (
+	"fmt"
+	"time"
+)
+
+// PermanentError signals that the operation should not be retried.
+type PermanentError struct {
+	Err error
+}
+
+// Permanent wraps the given err in a *PermanentError.
+func Permanent(err error) error {
+	if err == nil {
+		return nil
+	}
+	return &PermanentError{
+		Err: err,
+	}
+}
+
+// Error returns a string representation of the Permanent error.
+func (e *PermanentError) Error() string {
+	return e.Err.Error()
+}
+
+// Unwrap returns the wrapped error.
+func (e *PermanentError) Unwrap() error {
+	return e.Err
+}
+
+// RetryAfterError signals that the operation should be retried after the given duration.
+type RetryAfterError struct {
+	Duration time.Duration
+}
+
+// RetryAfter returns a RetryAfter error that specifies how long to wait before retrying.
+func RetryAfter(seconds int) error {
+	return &RetryAfterError{Duration: time.Duration(seconds) * time.Second}
+}
+
+// Error returns a string representation of the RetryAfter error.
+func (e *RetryAfterError) Error() string {
+	return fmt.Sprintf("retry after %s", e.Duration)
+}

Server/vendor/github.com/cenkalti/backoff/v5/exponential.go

@@ -0,0 +1,118 @@
+package backoff
+
+import (
+	"math/rand/v2"
+	"time"
+)
+
+/*
+ExponentialBackOff is a backoff implementation that increases the backoff
+period for each retry attempt using a randomization function that grows exponentially.
+
+NextBackOff() is calculated using the following formula:
+
+	randomized interval =
+	    RetryInterval * (random value in range [1 - RandomizationFactor, 1 + RandomizationFactor])
+
+In other words NextBackOff() will range between the randomization factor
+percentage below and above the retry interval.
+
+For example, given the following parameters:
+
+	RetryInterval = 2
+	RandomizationFactor = 0.5
+	Multiplier = 2
+
+the actual backoff period used in the next retry attempt will range between 1 and 3 seconds,
+multiplied by the exponential, that is, between 2 and 6 seconds.
+
+Note: MaxInterval caps the RetryInterval and not the randomized interval.
+
+Example: Given the following default arguments, for 9 tries the sequence will be:
+
+	Request #  RetryInterval (seconds)  Randomized Interval (seconds)
+
+	 1          0.5                     [0.25,   0.75]
+	 2          0.75                    [0.375,  1.125]
+	 3          1.125                   [0.562,  1.687]
+	 4          1.687                   [0.8435, 2.53]
+	 5          2.53                    [1.265,  3.795]
+	 6          3.795                   [1.897,  5.692]
+	 7          5.692                   [2.846,  8.538]
+	 8          8.538                   [4.269, 12.807]
+	 9         12.807                   [6.403, 19.210]
+
+Note: Implementation is not thread-safe.
+*/
+type ExponentialBackOff struct {
+	InitialInterval     time.Duration
+	RandomizationFactor float64
+	Multiplier          float64
+	MaxInterval         time.Duration
+
+	currentInterval time.Duration
+}
+
+// Default values for ExponentialBackOff.
+const (
+	DefaultInitialInterval     = 500 * time.Millisecond
+	DefaultRandomizationFactor = 0.5
+	DefaultMultiplier          = 1.5
+	DefaultMaxInterval         = 60 * time.Second
+)
+
+// NewExponentialBackOff creates an instance of ExponentialBackOff using default values.
+func NewExponentialBackOff() *ExponentialBackOff {
+	return &ExponentialBackOff{
+		InitialInterval:     DefaultInitialInterval,
+		RandomizationFactor: DefaultRandomizationFactor,
+		Multiplier:          DefaultMultiplier,
+		MaxInterval:         DefaultMaxInterval,
+	}
+}
+
+// Reset the interval back to the initial retry interval and restarts the timer.
+// Reset must be called before using b.
+func (b *ExponentialBackOff) Reset() {
+	b.currentInterval = b.InitialInterval
+}
+
+// NextBackOff calculates the next backoff interval using the formula:
+//
+//	Randomized interval = RetryInterval * (1 ± RandomizationFactor)
+func (b *ExponentialBackOff) NextBackOff() time.Duration {
+	if b.currentInterval == 0 {
+		b.currentInterval = b.InitialInterval
+	}
+
+	next := getRandomValueFromInterval(b.RandomizationFactor, rand.Float64(), b.currentInterval)
+	b.incrementCurrentInterval()
+	return next
+}
+
+// Increments the current interval by multiplying it with the multiplier.
+func (b *ExponentialBackOff) incrementCurrentInterval() {
+	// Check for overflow, if overflow is detected set the current interval to the max interval.
+	if float64(b.currentInterval) >= float64(b.MaxInterval)/b.Multiplier {
+		b.currentInterval = b.MaxInterval
+	} else {
+		b.currentInterval = time.Duration(float64(b.currentInterval) * b.Multiplier)
+	}
+}
+
+// Returns a random value from the following interval:
+//
+//	[currentInterval - randomizationFactor * currentInterval, currentInterval + randomizationFactor * currentInterval].
+func getRandomValueFromInterval(randomizationFactor, random float64, currentInterval time.Duration) time.Duration {
+	if randomizationFactor == 0 {
+		return currentInterval // make sure no randomness is used when randomizationFactor is 0.
+	}
+	var delta = randomizationFactor * float64(currentInterval)
+	var minInterval = float64(currentInterval) - delta
+	var maxInterval = float64(currentInterval) + delta
+
+	// Get a random value from the range [minInterval, maxInterval].
+	// The formula used below has a +1 because if the minInterval is 1 and the maxInterval is 3 then
+	// we want a 33% chance for selecting either 1, 2 or 3.
+	return time.Duration(minInterval + (random * (maxInterval - minInterval + 1)))
+}

Server/vendor/github.com/cenkalti/backoff/v5/retry.go

@@ -0,0 +1,139 @@
+package backoff
+
+import (
+	"context"
+	"errors"
+	"time"
+)
+
+// DefaultMaxElapsedTime sets a default limit for the total retry duration.
+const DefaultMaxElapsedTime = 15 * time.Minute
+
+// Operation is a function that attempts an operation and may be retried.
+type Operation[T any] func() (T, error)
+
+// Notify is a function called on operation error with the error and backoff duration.
+type Notify func(error, time.Duration)
+
+// retryOptions holds configuration settings for the retry mechanism.
+type retryOptions struct {
+	BackOff        BackOff       // Strategy for calculating backoff periods.
+	Timer          timer         // Timer to manage retry delays.
+	Notify         Notify        // Optional function to notify on each retry error.
+	MaxTries       uint          // Maximum number of retry attempts.
+	MaxElapsedTime time.Duration // Maximum total time for all retries.
+}
+
+type RetryOption func(*retryOptions)
+
+// WithBackOff configures a custom backoff strategy.
+func WithBackOff(b BackOff) RetryOption {
+	return func(args *retryOptions) {
+		args.BackOff = b
+	}
+}
+
+// withTimer sets a custom timer for managing delays between retries.
+func withTimer(t timer) RetryOption {
+	return func(args *retryOptions) {
+		args.Timer = t
+	}
+}
+
+// WithNotify sets a notification function to handle retry errors.
+func WithNotify(n Notify) RetryOption {
+	return func(args *retryOptions) {
+		args.Notify = n
+	}
+}
+
+// WithMaxTries limits the number of all attempts.
+func WithMaxTries(n uint) RetryOption {
+	return func(args *retryOptions) {
+		args.MaxTries = n
+	}
+}
+
+// WithMaxElapsedTime limits the total duration for retry attempts.
+func WithMaxElapsedTime(d time.Duration) RetryOption {
+	return func(args *retryOptions) {
+		args.MaxElapsedTime = d
+	}
+}
+
+// Retry attempts the operation until success, a permanent error, or backoff completion.
+// It ensures the operation is executed at least once.
+//
+// Returns the operation result or error if retries are exhausted or context is cancelled.
+func Retry[T any](ctx context.Context, operation Operation[T], opts ...RetryOption) (T, error) {
+	// Initialize default retry options.
+	args := &retryOptions{
+		BackOff:        NewExponentialBackOff(),
+		Timer:          &defaultTimer{},
+		MaxElapsedTime: DefaultMaxElapsedTime,
+	}
+
+	// Apply user-provided options to the default settings.
+	for _, opt := range opts {
+		opt(args)
+	}
+
+	defer args.Timer.Stop()
+
+	startedAt := time.Now()
+	args.BackOff.Reset()
+	for numTries := uint(1); ; numTries++ {
+		// Execute the operation.
+		res, err := operation()
+		if err == nil {
+			return res, nil
+		}
+
+		// Stop retrying if maximum tries exceeded.
+		if args.MaxTries > 0 && numTries >= args.MaxTries {
+			return res, err
+		}
+
+		// Handle permanent errors without retrying.
+		var permanent *PermanentError
+		if errors.As(err, &permanent) {
+			return res, permanent.Unwrap()
+		}
+
+		// Stop retrying if context is cancelled.
+		if cerr := context.Cause(ctx); cerr != nil {
+			return res, cerr
+		}
+
+		// Calculate next backoff duration.
+		next := args.BackOff.NextBackOff()
+		if next == Stop {
+			return res, err
+		}
+
+		// Reset backoff if RetryAfterError is encountered.
+		var retryAfter *RetryAfterError
+		if errors.As(err, &retryAfter) {
+			next = retryAfter.Duration
+			args.BackOff.Reset()
+		}
+
+		// Stop retrying if maximum elapsed time exceeded.
+		if args.MaxElapsedTime > 0 && time.Since(startedAt)+next > args.MaxElapsedTime {
+			return res, err
+		}
+
+		// Notify on error if a notifier function is provided.
+		if args.Notify != nil {
+			args.Notify(err, next)
+		}
+
+		// Wait for the next backoff period or context cancellation.
+		args.Timer.Start(next)
+		select {
+		case <-args.Timer.C():
+		case <-ctx.Done():
+			return res, context.Cause(ctx)
+		}
+	}
+}

Server/vendor/github.com/cenkalti/backoff/v5/ticker.go

@@ -0,0 +1,83 @@
+package backoff
+
+import (
+	"sync"
+	"time"
+)
+
+// Ticker holds a channel that delivers `ticks' of a clock at times reported by a BackOff.
+//
+// Ticks will continue to arrive when the previous operation is still running,
+// so operations that take a while to fail could run in quick succession.
+type Ticker struct {
+	C        <-chan time.Time
+	c        chan time.Time
+	b        BackOff
+	timer    timer
+	stop     chan struct{}
+	stopOnce sync.Once
+}
+
+// NewTicker returns a new Ticker containing a channel that will send
+// the time at times specified by the BackOff argument. Ticker is
+// guaranteed to tick at least once.  The channel is closed when Stop
+// method is called or BackOff stops. It is not safe to manipulate the
+// provided backoff policy (notably calling NextBackOff or Reset)
+// while the ticker is running.
+func NewTicker(b BackOff) *Ticker {
+	c := make(chan time.Time)
+	t := &Ticker{
+		C:     c,
+		c:     c,
+		b:     b,
+		timer: &defaultTimer{},
+		stop:  make(chan struct{}),
+	}
+	t.b.Reset()
+	go t.run()
+	return t
+}
+
+// Stop turns off a ticker. After Stop, no more ticks will be sent.
+func (t *Ticker) Stop() {
+	t.stopOnce.Do(func() { close(t.stop) })
+}
+
+func (t *Ticker) run() {
+	c := t.c
+	defer close(c)
+
+	// Ticker is guaranteed to tick at least once.
+	afterC := t.send(time.Now())
+
+	for {
+		if afterC == nil {
+			return
+		}
+
+		select {
+		case tick := <-afterC:
+			afterC = t.send(tick)
+		case <-t.stop:
+			t.c = nil // Prevent future ticks from being sent to the channel.
+			return
+		}
+	}
+}
+
+func (t *Ticker) send(tick time.Time) <-chan time.Time {
+	select {
+	case t.c <- tick:
+	case <-t.stop:
+		return nil
+	}
+
+	next := t.b.NextBackOff()
+	if next == Stop {
+		t.Stop()
+		return nil
+	}
+
+	t.timer.Start(next)
+	return t.timer.C()
+}

Server/vendor/github.com/cenkalti/backoff/v5/timer.go

@@ -0,0 +1,35 @@
+package backoff
+
+import "time"
+
+type timer interface {
+	Start(duration time.Duration)
+	Stop()
+	C() <-chan time.Time
+}
+
+// defaultTimer implements Timer interface using time.Timer
+type defaultTimer struct {
+	timer *time.Timer
+}
+
+// C returns the timers channel which receives the current time when the timer fires.
+func (t *defaultTimer) C() <-chan time.Time {
+	return t.timer.C
+}
+
+// Start starts the timer to fire after the given duration
+func (t *defaultTimer) Start(duration time.Duration) {
+	if t.timer == nil {
+		t.timer = time.NewTimer(duration)
+	} else {
+		t.timer.Reset(duration)
+	}
+}
+
+// Stop is called when the timer is not used anymore and resources may be freed.
+func (t *defaultTimer) Stop() {
+	if t.timer != nil {
+		t.timer.Stop()
+	}
+}