constellation/internal/retry/retry.go

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/*
Copyright (c) Edgeless Systems GmbH
SPDX-License-Identifier: AGPL-3.0-only
*/
// Package retry provides a simple interface for retrying operations.
package retry
import (
"context"
"time"
"k8s.io/utils/clock"
)
// IntervalRetrier retries a call with an interval. The call is defined in the Doer property.
type IntervalRetrier struct {
interval time.Duration
doer Doer
clock clock.WithTicker
retriable func(error) bool
}
// NewIntervalRetrier returns a new IntervalRetrier. The optional clock is used for testing.
func NewIntervalRetrier(doer Doer, interval time.Duration, retriable func(error) bool, optClock ...clock.WithTicker) *IntervalRetrier {
var clock clock.WithTicker = clock.RealClock{}
if len(optClock) > 0 {
clock = optClock[0]
}
return &IntervalRetrier{
interval: interval,
doer: doer,
clock: clock,
retriable: retriable,
}
}
// Do retries performing a call until it succeeds, returns a permanent error or the context is cancelled.
func (r *IntervalRetrier) Do(ctx context.Context) error {
ticker := r.clock.NewTicker(r.interval)
defer ticker.Stop()
for {
err := r.doer.Do(ctx)
if err == nil {
return nil
}
if !r.retriable(err) {
return err
}
select {
case <-ctx.Done():
return ctx.Err()
case <-ticker.C():
}
}
}
// Doer does something and returns an error.
type Doer interface {
// Do performs an operation.
//
// It should return an error that can be checked for retriability.
Do(ctx context.Context) error
}