feat(modules): migrate to go modules and bump go version 1.14.4

- migrate to go module
- bump go version 1.14.4

Signed-off-by: prateekpandey14 <prateek.pandey@mayadata.io>

vendor/k8s.io/client-go/tools/cache/reflector.go

@@ -17,6 +17,7 @@ limitations under the License.
 package cache
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -24,7 +25,6 @@ import (
 	"net"
 	"net/url"
 	"reflect"
-	"strings"
 	"sync"
 	"syscall"
 	"time"
@@ -38,6 +38,7 @@ import (
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/apimachinery/pkg/watch"
+	"k8s.io/client-go/tools/pager"
 	"k8s.io/klog"
 	"k8s.io/utils/trace"
 )
@@ -68,6 +69,9 @@ type Reflector struct {
 	lastSyncResourceVersion string
 	// lastSyncResourceVersionMutex guards read/write access to lastSyncResourceVersion
 	lastSyncResourceVersionMutex sync.RWMutex
+	// WatchListPageSize is the requested chunk size of initial and resync watch lists.
+	// Defaults to pager.PageSize.
+	WatchListPageSize int64
 }
 
 var (
@@ -79,7 +83,7 @@ var (
 // NewNamespaceKeyedIndexerAndReflector creates an Indexer and a Reflector
 // The indexer is configured to key on namespace
 func NewNamespaceKeyedIndexerAndReflector(lw ListerWatcher, expectedType interface{}, resyncPeriod time.Duration) (indexer Indexer, reflector *Reflector) {
-	indexer = NewIndexer(MetaNamespaceKeyFunc, Indexers{"namespace": MetaNamespaceIndexFunc})
+	indexer = NewIndexer(MetaNamespaceKeyFunc, Indexers{NamespaceIndex: MetaNamespaceIndexFunc})
 	reflector = NewReflector(lw, expectedType, indexer, resyncPeriod)
 	return indexer, reflector
 }
@@ -108,11 +112,6 @@ func NewNamedReflector(name string, lw ListerWatcher, expectedType interface{},
 	return r
 }
 
-func makeValidPrometheusMetricLabel(in string) string {
-	// this isn't perfect, but it removes our common characters
-	return strings.NewReplacer("/", "_", ".", "_", "-", "_", ":", "_").Replace(in)
-}
-
 // internalPackages are packages that ignored when creating a default reflector name. These packages are in the common
 // call chains to NewReflector, so they'd be low entropy names for reflectors
 var internalPackages = []string{"client-go/tools/cache/"}
@@ -179,7 +178,16 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 					panicCh <- r
 				}
 			}()
-			list, err = r.listerWatcher.List(options)
+			// Attempt to gather list in chunks, if supported by listerWatcher, if not, the first
+			// list request will return the full response.
+			pager := pager.New(pager.SimplePageFunc(func(opts metav1.ListOptions) (runtime.Object, error) {
+				return r.listerWatcher.List(opts)
+			}))
+			if r.WatchListPageSize != 0 {
+				pager.PageSize = r.WatchListPageSize
+			}
+			// Pager falls back to full list if paginated list calls fail due to an "Expired" error.
+			list, err = pager.List(context.Background(), options)
 			close(listCh)
 		}()
 		select {
@@ -257,8 +265,15 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 			// We want to avoid situations of hanging watchers. Stop any wachers that do not
 			// receive any events within the timeout window.
 			TimeoutSeconds: &timeoutSeconds,
+			// To reduce load on kube-apiserver on watch restarts, you may enable watch bookmarks.
+			// Reflector doesn't assume bookmarks are returned at all (if the server do not support
+			// watch bookmarks, it will ignore this field).
+			// Disabled in Alpha release of watch bookmarks feature.
+			AllowWatchBookmarks: false,
 		}
 
+		// start the clock before sending the request, since some proxies won't flush headers until after the first watch event is sent
+		start := r.clock.Now()
 		w, err := r.listerWatcher.Watch(options)
 		if err != nil {
 			switch err {
@@ -284,7 +299,7 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 			return nil
 		}
 
-		if err := r.watchHandler(w, &resourceVersion, resyncerrc, stopCh); err != nil {
+		if err := r.watchHandler(start, w, &resourceVersion, resyncerrc, stopCh); err != nil {
 			if err != errorStopRequested {
 				klog.Warningf("%s: watch of %v ended with: %v", r.name, r.expectedType, err)
 			}
@@ -303,8 +318,7 @@ func (r *Reflector) syncWith(items []runtime.Object, resourceVersion string) err
 }
 
 // watchHandler watches w and keeps *resourceVersion up to date.
-func (r *Reflector) watchHandler(w watch.Interface, resourceVersion *string, errc chan error, stopCh <-chan struct{}) error {
-	start := r.clock.Now()
+func (r *Reflector) watchHandler(start time.Time, w watch.Interface, resourceVersion *string, errc chan error, stopCh <-chan struct{}) error {
 	eventCount := 0
 
 	// Stopping the watcher should be idempotent and if we return from this function there's no way
@@ -354,6 +368,8 @@ loop:
 				if err != nil {
 					utilruntime.HandleError(fmt.Errorf("%s: unable to delete watch event object (%#v) from store: %v", r.name, event.Object, err))
 				}
+			case watch.Bookmark:
+				// A `Bookmark` means watch has synced here, just update the resourceVersion
 			default:
 				utilruntime.HandleError(fmt.Errorf("%s: unable to understand watch event %#v", r.name, event))
 			}
@@ -363,7 +379,7 @@ loop:
 		}
 	}
 
-	watchDuration := r.clock.Now().Sub(start)
+	watchDuration := r.clock.Since(start)
 	if watchDuration < 1*time.Second && eventCount == 0 {
 		return fmt.Errorf("very short watch: %s: Unexpected watch close - watch lasted less than a second and no items received", r.name)
 	}