retry.go

// Copyright 2016 The Cockroach 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 util

import (
	"time"

	"github.com/cockroachdb/cockroach/pkg/util/timeutil"
)

// RetryForDuration will retry the given function until it either returns
// without error, or the given duration has elapsed. The function is invoked
// immediately at first and then successively with an exponential backoff
// starting at 1ns and ending at the specified duration.
func RetryForDuration(duration time.Duration, fn func() error) error {
	deadline := timeutil.Now().Add(duration)
	var lastErr error
	for wait := time.Duration(1); timeutil.Now().Before(deadline); wait *= 2 {
		lastErr = fn()
		if lastErr == nil {
			return nil
		}
		if wait > time.Second {
			wait = time.Second
		}
		time.Sleep(wait)
	}
	return lastErr
}