blob: 946dbf2458a07928dfa22fd9f0f30dcb35d947f1 [file] [log] [blame]
/*
* Copyright 2018-present Open Networking Foundation
* 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 kvstore
import (
"bytes"
"context"
"fmt"
"math"
"math/rand"
"time"
)
const (
minRetryInterval = 100
maxRetryInterval = 5000
incrementalFactor = 1.2
jitter = 0.2
)
// ToString converts an interface value to a string. The interface should either be of
// a string type or []byte. Otherwise, an error is returned.
func ToString(value interface{}) (string, error) {
switch t := value.(type) {
case []byte:
return string(value.([]byte)), nil
case string:
return value.(string), nil
default:
return "", fmt.Errorf("unexpected-type-%T", t)
}
}
// ToByte converts an interface value to a []byte. The interface should either be of
// a string type or []byte. Otherwise, an error is returned.
func ToByte(value interface{}) ([]byte, error) {
switch t := value.(type) {
case []byte:
return value.([]byte), nil
case string:
return []byte(value.(string)), nil
default:
return nil, fmt.Errorf("unexpected-type-%T", t)
}
}
// Helper function to verify mostly whether the content of two interface types are the same. Focus is []byte and
// string types
func isEqual(val1 interface{}, val2 interface{}) bool {
b1, err := ToByte(val1)
b2, er := ToByte(val2)
if err == nil && er == nil {
return bytes.Equal(b1, b2)
}
return val1 == val2
}
// backoff waits an amount of time that is proportional to the attempt value. The wait time in a range of
// minRetryInterval and maxRetryInterval.
func backoff(ctx context.Context, attempt int) error {
if attempt == 0 {
return nil
}
backoff := int(minRetryInterval + incrementalFactor*math.Exp(float64(attempt)))
backoff *= 1 + int(jitter*(rand.Float64()*2-1))
if backoff > maxRetryInterval {
backoff = maxRetryInterval
}
ticker := time.NewTicker(time.Duration(backoff) * time.Millisecond)
defer ticker.Stop()
select {
case <-ctx.Done():
return ctx.Err()
case <-ticker.C:
}
return nil
}