Merge pull request #16315 from pravisankar/router-change-to-informer

Automatic merge from submit-queue.

Replaced event queue based watching resources in router with shared informers

- Custom shared informer is used to leverage namespace, label and field filtering.
  (Auto generated shared informer does not allow this)
- Listing resources by shared informers doesn't order by resource version/creation time.
  So custom lister for routes is used to order the route list by creation time and this
  will allow oldest route to be processed before new route to claim the host name.
- Synchronization with the informer queue and cache is a bit difficult as the cache could
  have newer changes than what was pushed on to the queue. Luckily We only care about the
  first sync to avoid 503 status code for routes.
- Handling first sync:
  * Informers are started with no registered event handlers
  * Wait for all informers to be synced
  * Block router reload
  * Get list of items from informers store and process manually
  * Perform router reload
  * Register router event handlers
  This guarantees first router sync is performed after processing all existing items.
- Subsequent router syncs rely on informer syncing sate and uses rate limiter to coalesce changes.

- Deleted eventQueue, no longer used

Trello card: https://trello.com/c/y6SFvOA7

pkg/cmd/infra/router/router.go

@@ -19,7 +19,7 @@ import (
 	"github.com/openshift/origin/pkg/cmd/util/variable"
 	projectclient "github.com/openshift/origin/pkg/project/generated/internalclientset/typed/project/internalversion"
 	routeapi "github.com/openshift/origin/pkg/route/apis/route"
-	routeclient "github.com/openshift/origin/pkg/route/generated/internalclientset/typed/route/internalversion"
+	routeinternalclientset "github.com/openshift/origin/pkg/route/generated/internalclientset"
 	"github.com/openshift/origin/pkg/router/controller"
 	controllerfactory "github.com/openshift/origin/pkg/router/controller/factory"
 )
@@ -33,9 +33,7 @@ type RouterSelection struct {
 	OverrideHostname bool
 
 	LabelSelector string
-	Labels        labels.Selector
 	FieldSelector string
-	Fields        fields.Selector
 
 	Namespace              string
 	NamespaceLabelSelector string
@@ -165,23 +163,15 @@ func (o *RouterSelection) Complete() error {
 		return fmt.Errorf("--override-hostname requires that --hostname-template be specified")
 	}
 	if len(o.LabelSelector) > 0 {
-		s, err := labels.Parse(o.LabelSelector)
-		if err != nil {
+		if _, err := labels.Parse(o.LabelSelector); err != nil {
 			return fmt.Errorf("label selector is not valid: %v", err)
 		}
-		o.Labels = s
-	} else {
-		o.Labels = labels.Everything()
 	}
 
 	if len(o.FieldSelector) > 0 {
-		s, err := fields.ParseSelector(o.FieldSelector)
-		if err != nil {
+		if _, err := fields.ParseSelector(o.FieldSelector); err != nil {
 			return fmt.Errorf("field selector is not valid: %v", err)
 		}
-		o.Fields = s
-	} else {
-		o.Fields = fields.Everything()
 	}
 
 	if len(o.ProjectLabelSelector) > 0 {
@@ -221,10 +211,10 @@ func (o *RouterSelection) Complete() error {
 }
 
 // NewFactory initializes a factory that will watch the requested routes
-func (o *RouterSelection) NewFactory(routeclient routeclient.RoutesGetter, projectclient projectclient.ProjectResourceInterface, kc kclientset.Interface) *controllerfactory.RouterControllerFactory {
+func (o *RouterSelection) NewFactory(routeclient routeinternalclientset.Interface, projectclient projectclient.ProjectResourceInterface, kc kclientset.Interface) *controllerfactory.RouterControllerFactory {
 	factory := controllerfactory.NewDefaultRouterControllerFactory(routeclient, kc)
-	factory.Labels = o.Labels
-	factory.Fields = o.Fields
+	factory.LabelSelector = o.LabelSelector
+	factory.FieldSelector = o.FieldSelector
 	factory.Namespace = o.Namespace
 	factory.ResyncInterval = o.ResyncInterval
 	switch {