Update template to use no change update env var

generator/funcs.go

@@ -2,6 +2,7 @@ package generator
 
 import (
 	"net/http"
+	"os"
 	"strings"
 	"text/template"
 
@@ -9,6 +10,10 @@ import (
 	"github.com/rancher/norman/types/convert"
 )
 
+const (
+	managementContextType = "mgmt"
+)
+
 func funcs() template.FuncMap {
 	return template.FuncMap{
 		"capitalize":          convert.Capitalize,
@@ -53,3 +58,21 @@ func getCollectionOutput(output, codeName string) string {
 	}
 	return convert.Capitalize(output)
 }
+
+// SyncOnlyChangedObjects check whether the CATTLE_SKIP_NO_CHANGE_UPDATE env var is
+// configured to skip the update handler for events on the management context
+// that do not contain a change to the object.
+func SyncOnlyChangedObjects() bool {
+	skipNoChangeUpdate := os.Getenv("CATTLE_SYNC_ONLY_CHANGED_OBJECTS")
+	if skipNoChangeUpdate == "" {
+		return false
+	}
+	parts := strings.Split(skipNoChangeUpdate, ",")
+
+	for _, part := range parts {
+		if part == managementContextType {
+			return true
+		}
+	}
+	return false
+}

generator/k8s_client_template.go

@@ -6,6 +6,7 @@ import (
 	"github.com/rancher/lasso/pkg/client"
 	"github.com/rancher/lasso/pkg/controller"
 	"github.com/rancher/norman/objectclient"
+	"github.com/rancher/norman/generator"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/client-go/rest"
 	{{.importPackage}}
@@ -26,7 +27,10 @@ func NewForConfig(cfg rest.Config) (Interface, error) {
 	if err := {{.prefix}}AddToScheme(scheme); err != nil {
 		return nil, err
 	}
-	controllerFactory, err := controller.NewSharedControllerFactoryFromConfig(&cfg, scheme)
+	sharedOpts := &controller.SharedControllerFactoryOptions{
+		SyncOnlyChangedObjects: generator.SyncOnlyChangedObjects(),
+	}
+	controllerFactory, err := controller.NewSharedControllerFactoryFromConfigWithOptions(&cfg, scheme, sharedOpts)
 	if err != nil {
 		return nil, err
 	}