rebase: update kubernetes to v1.20.0

updated kubernetes packages to latest
release.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

vendor/k8s.io/client-go/rest/warnings.go

@@ -0,0 +1,147 @@
+/*
+Copyright 2020 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 (
+	"fmt"
+	"io"
+	"net/http"
+	"sync"
+
+	"k8s.io/klog/v2"
+
+	"k8s.io/apimachinery/pkg/util/net"
+)
+
+// WarningHandler is an interface for handling warning headers
+type WarningHandler interface {
+	// HandleWarningHeader is called with the warn code, agent, and text when a warning header is countered.
+	HandleWarningHeader(code int, agent string, text string)
+}
+
+var (
+	defaultWarningHandler     WarningHandler = WarningLogger{}
+	defaultWarningHandlerLock sync.RWMutex
+)
+
+// SetDefaultWarningHandler sets the default handler clients use when warning headers are encountered.
+// By default, warnings are logged. Several built-in implementations are provided:
+//  - NoWarnings suppresses warnings.
+//  - WarningLogger logs warnings.
+//  - NewWarningWriter() outputs warnings to the provided writer.
+func SetDefaultWarningHandler(l WarningHandler) {
+	defaultWarningHandlerLock.Lock()
+	defer defaultWarningHandlerLock.Unlock()
+	defaultWarningHandler = l
+}
+func getDefaultWarningHandler() WarningHandler {
+	defaultWarningHandlerLock.RLock()
+	defer defaultWarningHandlerLock.RUnlock()
+	l := defaultWarningHandler
+	return l
+}
+
+// NoWarnings is an implementation of WarningHandler that suppresses warnings.
+type NoWarnings struct{}
+
+func (NoWarnings) HandleWarningHeader(code int, agent string, message string) {}
+
+// WarningLogger is an implementation of WarningHandler that logs code 299 warnings
+type WarningLogger struct{}
+
+func (WarningLogger) HandleWarningHeader(code int, agent string, message string) {
+	if code != 299 || len(message) == 0 {
+		return
+	}
+	klog.Warning(message)
+}
+
+type warningWriter struct {
+	// out is the writer to output warnings to
+	out io.Writer
+	// opts contains options controlling warning output
+	opts WarningWriterOptions
+	// writtenLock guards written and writtenCount
+	writtenLock  sync.Mutex
+	writtenCount int
+	written      map[string]struct{}
+}
+
+// WarningWriterOptions controls the behavior of a WarningHandler constructed using NewWarningWriter()
+type WarningWriterOptions struct {
+	// Deduplicate indicates a given warning message should only be written once.
+	// Setting this to true in a long-running process handling many warnings can result in increased memory use.
+	Deduplicate bool
+	// Color indicates that warning output can include ANSI color codes
+	Color bool
+}
+
+// NewWarningWriter returns an implementation of WarningHandler that outputs code 299 warnings to the specified writer.
+func NewWarningWriter(out io.Writer, opts WarningWriterOptions) *warningWriter {
+	h := &warningWriter{out: out, opts: opts}
+	if opts.Deduplicate {
+		h.written = map[string]struct{}{}
+	}
+	return h
+}
+
+const (
+	yellowColor = "\u001b[33;1m"
+	resetColor  = "\u001b[0m"
+)
+
+// HandleWarningHeader prints warnings with code=299 to the configured writer.
+func (w *warningWriter) HandleWarningHeader(code int, agent string, message string) {
+	if code != 299 || len(message) == 0 {
+		return
+	}
+
+	w.writtenLock.Lock()
+	defer w.writtenLock.Unlock()
+
+	if w.opts.Deduplicate {
+		if _, alreadyWritten := w.written[message]; alreadyWritten {
+			return
+		}
+		w.written[message] = struct{}{}
+	}
+	w.writtenCount++
+
+	if w.opts.Color {
+		fmt.Fprintf(w.out, "%sWarning:%s %s\n", yellowColor, resetColor, message)
+	} else {
+		fmt.Fprintf(w.out, "Warning: %s\n", message)
+	}
+}
+
+func (w *warningWriter) WarningCount() int {
+	w.writtenLock.Lock()
+	defer w.writtenLock.Unlock()
+	return w.writtenCount
+}
+
+func handleWarnings(headers http.Header, handler WarningHandler) []net.WarningHeader {
+	if handler == nil {
+		handler = getDefaultWarningHandler()
+	}
+
+	warnings, _ := net.ParseWarningHeaders(headers["Warning"])
+	for _, warning := range warnings {
+		handler.HandleWarningHeader(warning.Code, warning.Agent, warning.Text)
+	}
+	return warnings
+}