mirror of
https://github.com/TwiN/gatus.git
synced 2024-11-26 01:43:41 +01:00
108 lines
3.4 KiB
Go
108 lines
3.4 KiB
Go
/*
|
|
Copyright 2015 The Kubernetes 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 rest
|
|
|
|
import (
|
|
"net/url"
|
|
"time"
|
|
|
|
"k8s.io/apimachinery/pkg/util/sets"
|
|
"k8s.io/client-go/util/flowcontrol"
|
|
"k8s.io/klog"
|
|
)
|
|
|
|
// Set of resp. Codes that we backoff for.
|
|
// In general these should be errors that indicate a server is overloaded.
|
|
// These shouldn't be configured by any user, we set them based on conventions
|
|
// described in
|
|
var serverIsOverloadedSet = sets.NewInt(429)
|
|
var maxResponseCode = 499
|
|
|
|
type BackoffManager interface {
|
|
UpdateBackoff(actualUrl *url.URL, err error, responseCode int)
|
|
CalculateBackoff(actualUrl *url.URL) time.Duration
|
|
Sleep(d time.Duration)
|
|
}
|
|
|
|
// URLBackoff struct implements the semantics on top of Backoff which
|
|
// we need for URL specific exponential backoff.
|
|
type URLBackoff struct {
|
|
// Uses backoff as underlying implementation.
|
|
Backoff *flowcontrol.Backoff
|
|
}
|
|
|
|
// NoBackoff is a stub implementation, can be used for mocking or else as a default.
|
|
type NoBackoff struct {
|
|
}
|
|
|
|
func (n *NoBackoff) UpdateBackoff(actualUrl *url.URL, err error, responseCode int) {
|
|
// do nothing.
|
|
}
|
|
|
|
func (n *NoBackoff) CalculateBackoff(actualUrl *url.URL) time.Duration {
|
|
return 0 * time.Second
|
|
}
|
|
|
|
func (n *NoBackoff) Sleep(d time.Duration) {
|
|
time.Sleep(d)
|
|
}
|
|
|
|
// Disable makes the backoff trivial, i.e., sets it to zero. This might be used
|
|
// by tests which want to run 1000s of mock requests without slowing down.
|
|
func (b *URLBackoff) Disable() {
|
|
klog.V(4).Infof("Disabling backoff strategy")
|
|
b.Backoff = flowcontrol.NewBackOff(0*time.Second, 0*time.Second)
|
|
}
|
|
|
|
// baseUrlKey returns the key which urls will be mapped to.
|
|
// For example, 127.0.0.1:8080/api/v2/abcde -> 127.0.0.1:8080.
|
|
func (b *URLBackoff) baseUrlKey(rawurl *url.URL) string {
|
|
// Simple implementation for now, just the host.
|
|
// We may backoff specific paths (i.e. "pods") differentially
|
|
// in the future.
|
|
host, err := url.Parse(rawurl.String())
|
|
if err != nil {
|
|
klog.V(4).Infof("Error extracting url: %v", rawurl)
|
|
panic("bad url!")
|
|
}
|
|
return host.Host
|
|
}
|
|
|
|
// UpdateBackoff updates backoff metadata
|
|
func (b *URLBackoff) UpdateBackoff(actualUrl *url.URL, err error, responseCode int) {
|
|
// range for retry counts that we store is [0,13]
|
|
if responseCode > maxResponseCode || serverIsOverloadedSet.Has(responseCode) {
|
|
b.Backoff.Next(b.baseUrlKey(actualUrl), b.Backoff.Clock.Now())
|
|
return
|
|
} else if responseCode >= 300 || err != nil {
|
|
klog.V(4).Infof("Client is returning errors: code %v, error %v", responseCode, err)
|
|
}
|
|
|
|
//If we got this far, there is no backoff required for this URL anymore.
|
|
b.Backoff.Reset(b.baseUrlKey(actualUrl))
|
|
}
|
|
|
|
// CalculateBackoff takes a url and back's off exponentially,
|
|
// based on its knowledge of existing failures.
|
|
func (b *URLBackoff) CalculateBackoff(actualUrl *url.URL) time.Duration {
|
|
return b.Backoff.Get(b.baseUrlKey(actualUrl))
|
|
}
|
|
|
|
func (b *URLBackoff) Sleep(d time.Duration) {
|
|
b.Backoff.Clock.Sleep(d)
|
|
}
|