k8s: fix a bug in k8s version parsing. Fixes #3870 (#3917)

internal/k8s/watch.go

@@ -4,9 +4,9 @@ import (
 	"context"
 	"fmt"
 	"net/http"
-	"strconv"
 	"time"
 
+	"github.com/blang/semver"
 	"github.com/pkg/errors"
 	v1 "k8s.io/api/core/v1"
 	apiErrors "k8s.io/apimachinery/pkg/api/errors"
@@ -15,6 +15,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/apimachinery/pkg/version"
 	"k8s.io/apimachinery/pkg/watch"
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/metadata/metadatainformer"
@@ -276,6 +277,20 @@ func (kCli K8sClient) WatchServices(ctx context.Context, ns Namespace, ls labels
 	return ch, nil
 }
 
+func supportsPartialMetadata(v *version.Info) bool {
+	k1dot15, err := semver.ParseTolerant("v1.15.0")
+	if err != nil {
+		return false
+	}
+	version, err := semver.ParseTolerant(v.GitVersion)
+	if err != nil {
+		// If we don't recognize the version number,
+		// assume this server doesn't support metadata.
+		return false
+	}
+	return version.GTE(k1dot15)
+}
+
 func (kCli K8sClient) WatchMeta(ctx context.Context, gvk schema.GroupVersionKind, ns Namespace) (<-chan ObjectMeta, error) {
 	gvr, err := kCli.gvr(ctx, gvk)
 	if err != nil {
@@ -287,11 +302,10 @@ func (kCli K8sClient) WatchMeta(ctx context.Context, gvk schema.GroupVersionKind
 		return nil, errors.Wrap(err, "WatchMeta")
 	}
 
-	minor, err := strconv.Atoi(version.Minor)
-	if version.Major == "1" && err == nil && minor <= 14 {
-		return kCli.watchMeta14Minus(ctx, gvr, ns)
+	if supportsPartialMetadata(version) {
+		return kCli.watchMeta15Plus(ctx, gvr, ns)
 	}
-	return kCli.watchMeta15Plus(ctx, gvr, ns)
+	return kCli.watchMeta14Minus(ctx, gvr, ns)
 }
 
 // workaround a bug in client-go

internal/k8s/watch_test.go

@@ -311,7 +311,7 @@ func TestK8sClient_WatchMetaBackfillK8s14(t *testing.T) {
 	tf := newWatchTestFixture(t)
 	defer tf.TearDown()
 
-	tf.version.Minor = "14"
+	tf.version.GitVersion = "v1.14.1"
 
 	pod1 := fakePod(PodID("abcd"), "efgh")
 	pod2 := fakePod(PodID("1234"), "hieruyge")
@@ -323,6 +323,38 @@ func TestK8sClient_WatchMetaBackfillK8s14(t *testing.T) {
 	tf.assertMeta(expected, ch)
 }
 
+type partialMetaTestCase struct {
+	v        string
+	expected bool
+}
+
+func TestSupportsPartialMeta(t *testing.T) {
+	cases := []partialMetaTestCase{
+		// minikube
+		partialMetaTestCase{"v1.19.1", true},
+		partialMetaTestCase{"v1.15.0", true},
+		partialMetaTestCase{"v1.14.0", false},
+
+		// gke
+		partialMetaTestCase{"v1.18.10-gke.601", true},
+		partialMetaTestCase{"v1.15.10-gke.601", true},
+		partialMetaTestCase{"v1.14.10-gke.601", false},
+
+		// microk8s
+		partialMetaTestCase{"v1.19.3-34+fa32ff1c160058", true},
+		partialMetaTestCase{"v1.15.3-34+fa32ff1c160058", true},
+		partialMetaTestCase{"v1.14.3-34+fa32ff1c160058", false},
+
+		partialMetaTestCase{"garbage", false},
+	}
+	for _, c := range cases {
+		c := c
+		t.Run(c.v, func(t *testing.T) {
+			assert.Equal(t, c.expected, supportsPartialMetadata(&version.Info{GitVersion: c.v}))
+		})
+	}
+}
+
 type watchTestFixture struct {
 	t    *testing.T
 	kCli K8sClient
@@ -384,7 +416,7 @@ func newWatchTestFixture(t *testing.T) *watchTestFixture {
 	mcs.PrependWatchReactor("*", wr)
 	ret.metadata = mcs
 
-	version := &version.Info{Major: "1", Minor: "19"}
+	version := &version.Info{Major: "1", Minor: "19", GitVersion: "v1.19.1"}
 	di := &difake.FakeDiscovery{
 		Fake:               &ktesting.Fake{},
 		FakedServerVersion: version,