Import of https://github.com/ciena/voltctl at commit 40d61fbf3f910ed4017cf67c9c79e8e1f82a33a5
Change-Id: I8464c59e60d76cb8612891db3303878975b5416c
diff --git a/vendor/k8s.io/client-go/rest/urlbackoff.go b/vendor/k8s.io/client-go/rest/urlbackoff.go
new file mode 100644
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+++ b/vendor/k8s.io/client-go/rest/urlbackoff.go
@@ -0,0 +1,107 @@
+/*
+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)
+}