mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-11-27 16:50:23 +00:00
97 lines
2.7 KiB
Go
97 lines
2.7 KiB
Go
/*
|
|
*
|
|
* Copyright 2017 gRPC 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 grpc
|
|
|
|
import (
|
|
"math/rand"
|
|
"time"
|
|
)
|
|
|
|
// DefaultBackoffConfig uses values specified for backoff in
|
|
// https://github.com/grpc/grpc/blob/master/doc/connection-backoff.md.
|
|
var DefaultBackoffConfig = BackoffConfig{
|
|
MaxDelay: 120 * time.Second,
|
|
baseDelay: 1.0 * time.Second,
|
|
factor: 1.6,
|
|
jitter: 0.2,
|
|
}
|
|
|
|
// backoffStrategy defines the methodology for backing off after a grpc
|
|
// connection failure.
|
|
//
|
|
// This is unexported until the gRPC project decides whether or not to allow
|
|
// alternative backoff strategies. Once a decision is made, this type and its
|
|
// method may be exported.
|
|
type backoffStrategy interface {
|
|
// backoff returns the amount of time to wait before the next retry given
|
|
// the number of consecutive failures.
|
|
backoff(retries int) time.Duration
|
|
}
|
|
|
|
// BackoffConfig defines the parameters for the default gRPC backoff strategy.
|
|
type BackoffConfig struct {
|
|
// MaxDelay is the upper bound of backoff delay.
|
|
MaxDelay time.Duration
|
|
|
|
// TODO(stevvooe): The following fields are not exported, as allowing
|
|
// changes would violate the current gRPC specification for backoff. If
|
|
// gRPC decides to allow more interesting backoff strategies, these fields
|
|
// may be opened up in the future.
|
|
|
|
// baseDelay is the amount of time to wait before retrying after the first
|
|
// failure.
|
|
baseDelay time.Duration
|
|
|
|
// factor is applied to the backoff after each retry.
|
|
factor float64
|
|
|
|
// jitter provides a range to randomize backoff delays.
|
|
jitter float64
|
|
}
|
|
|
|
func setDefaults(bc *BackoffConfig) {
|
|
md := bc.MaxDelay
|
|
*bc = DefaultBackoffConfig
|
|
|
|
if md > 0 {
|
|
bc.MaxDelay = md
|
|
}
|
|
}
|
|
|
|
func (bc BackoffConfig) backoff(retries int) time.Duration {
|
|
if retries == 0 {
|
|
return bc.baseDelay
|
|
}
|
|
backoff, max := float64(bc.baseDelay), float64(bc.MaxDelay)
|
|
for backoff < max && retries > 0 {
|
|
backoff *= bc.factor
|
|
retries--
|
|
}
|
|
if backoff > max {
|
|
backoff = max
|
|
}
|
|
// Randomize backoff delays so that if a cluster of requests start at
|
|
// the same time, they won't operate in lockstep.
|
|
backoff *= 1 + bc.jitter*(rand.Float64()*2-1)
|
|
if backoff < 0 {
|
|
return 0
|
|
}
|
|
return time.Duration(backoff)
|
|
}
|