Merge pull request #114632 from neolit123/1.27-fix-dry-run-server-version

kubeadm: handle dry run GET actions from fake discovery

cmd/kubeadm/app/util/apiclient/dryrunclient.go

@@ -119,9 +119,17 @@ func NewDryRunClientWithOpts(opts DryRunClientOptions) clientset.Interface {
 			Reaction: func(action core.Action) (bool, runtime.Object, error) {
 				getAction, ok := action.(core.GetAction)
 				if !ok {
+					// If the GetAction cast fails, this could be an ActionImpl with a "get" verb.
+					// Such actions could be invoked from any of the fake discovery calls, such as ServerVersion().
+					// Attempt the cast to ActionImpl and construct a GetActionImpl from it.
+					actionImpl, ok := action.(core.ActionImpl)
+					if ok {
+						getAction = core.GetActionImpl{ActionImpl: actionImpl}
+					} else {
 						// something's wrong, we can't handle this event
 						return true, nil, errors.New("can't cast get reactor event action object to GetAction interface")
 					}
+				}
 				handled, obj, err := opts.Getter.HandleGetAction(getAction)
 
 				if opts.PrintGETAndLIST {

cmd/kubeadm/app/util/apiclient/dryrunclient_test.go

@@ -18,12 +18,15 @@ package apiclient
 
 import (
 	"bytes"
+	"io"
 	"testing"
 
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	rbac "k8s.io/api/rbac/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	pkgversion "k8s.io/apimachinery/pkg/version"
+	fakediscovery "k8s.io/client-go/discovery/fake"
 	core "k8s.io/client-go/testing"
 )
 
@@ -109,3 +112,24 @@ func TestLogDryRunAction(t *testing.T) {
 		})
 	}
 }
+
+func TestDiscoveryServerVersion(t *testing.T) {
+	dryRunGetter := &InitDryRunGetter{
+		controlPlaneName: "controlPlane",
+		serviceSubnet:    "serviceSubnet",
+	}
+	c := NewDryRunClient(dryRunGetter, io.Discard)
+	fakeclientDiscovery, ok := c.Discovery().(*fakediscovery.FakeDiscovery)
+	if !ok {
+		t.Fatal("could not obtain FakeDiscovery from dry run client")
+	}
+	const gitVersion = "foo"
+	fakeclientDiscovery.FakedServerVersion = &pkgversion.Info{GitVersion: gitVersion}
+	ver, err := c.Discovery().ServerVersion()
+	if err != nil {
+		t.Fatalf("Get ServerVersion failed.: %v", err)
+	}
+	if ver.GitVersion != gitVersion {
+		t.Fatalf("GitVersion did not match, expected %s, got %s", gitVersion, ver.GitVersion)
+	}
+}