Fetch .Capabilities.APIVersions lazily

Signed-off-by: Eric Latham <ericoliverlatham@gmail.com>

pkg/action/action.go

@@ -97,6 +97,18 @@ type Configuration struct {
 	Log func(string, ...interface{})
 }
 
+// chartNeedsAPIVersions returns true if any template in the given Chart references .Capabilities.APIVersions.
+func chartNeedsAPIVersions(chart *chart.Chart) bool {
+	if chart != nil {
+		for _, template := range chart.Templates {
+			if bytes.Contains(template.Data, []byte(".Capabilities.APIVersions")) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
 // renderResources renders the templates in a chart
 //
 // TODO: This function is badly in need of a refactor.
@@ -107,7 +119,7 @@ func (cfg *Configuration) renderResources(ch *chart.Chart, values chartutil.Valu
 	hs := []*release.Hook{}
 	b := bytes.NewBuffer(nil)
 
-	caps, err := cfg.getCapabilities()
+	caps, err := cfg.getCapabilities(ch)
 	if err != nil {
 		return hs, b, "", err
 	}
@@ -243,7 +255,7 @@ type RESTClientGetter interface {
 type DebugLog func(format string, v ...interface{})
 
 // capabilities builds a Capabilities from discovery information.
-func (cfg *Configuration) getCapabilities() (*chartutil.Capabilities, error) {
+func (cfg *Configuration) getCapabilities(ch *chart.Chart) (*chartutil.Capabilities, error) {
 	if cfg.Capabilities != nil {
 		return cfg.Capabilities, nil
 	}
@@ -257,18 +269,23 @@ func (cfg *Configuration) getCapabilities() (*chartutil.Capabilities, error) {
 	if err != nil {
 		return nil, errors.Wrap(err, "could not get server version from Kubernetes")
 	}
-	// Issue #6361:
-	// Client-Go emits an error when an API service is registered but unimplemented.
-	// We trap that error here and print a warning. But since the discovery client continues
-	// building the API object, it is correctly populated with all valid APIs.
-	// See https://github.com/kubernetes/kubernetes/issues/72051#issuecomment-521157642
-	apiVersions, err := GetVersionSet(dc)
-	if err != nil {
-		if discovery.IsGroupDiscoveryFailedError(err) {
-			cfg.Log("WARNING: The Kubernetes server has an orphaned API service. Server reports: %s", err)
-			cfg.Log("WARNING: To fix this, kubectl delete apiservice <service-name>")
-		} else {
-			return nil, errors.Wrap(err, "could not get apiVersions from Kubernetes")
+
+	// Only fetch APIVersions if the chart needs it
+	var apiVersions chartutil.VersionSet
+	if chartNeedsAPIVersions(ch) {
+		// Issue #6361:
+		// Client-Go emits an error when an API service is registered but unimplemented.
+		// We trap that error here and print a warning. But since the discovery client continues
+		// building the API object, it is correctly populated with all valid APIs.
+		// See https://github.com/kubernetes/kubernetes/issues/72051#issuecomment-521157642
+		apiVersions, err = GetVersionSet(dc)
+		if err != nil {
+			if discovery.IsGroupDiscoveryFailedError(err) {
+				cfg.Log("WARNING: The Kubernetes server has an orphaned API service. Server reports: %s", err)
+				cfg.Log("WARNING: To fix this, kubectl delete apiservice <service-name>")
+			} else {
+				return nil, errors.Wrap(err, "could not get apiVersions from Kubernetes")
+			}
 		}
 	}
 

pkg/action/action_test.go

@@ -20,6 +20,7 @@ import (
 	"io"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
 	fakeclientset "k8s.io/client-go/kubernetes/fake"
 
 	"helm.sh/helm/v3/pkg/chart"
@@ -273,6 +274,19 @@ func namedReleaseStub(name string, status release.Status) *release.Release {
 	}
 }
 
+func Test_chartNeedsAPIVersions(t *testing.T) {
+	is := assert.New(t)
+	is.Equal(chartNeedsAPIVersions(nil), false)
+	ch := &chart.Chart{Metadata: &chart.Metadata{APIVersion: "v1", Name: "test", Version: "0.1.0"}}
+	is.Equal(chartNeedsAPIVersions(ch), false)
+	ch.Templates = append(ch.Templates, &chart.File{Name: "templates/hello", Data: []byte("hello: world")})
+	is.Equal(chartNeedsAPIVersions(ch), false)
+	ch.Templates = append(ch.Templates, &chart.File{Name: "templates/kube-version", Data: []byte("{{ .Capabilities.KubeVersion }}")})
+	is.Equal(chartNeedsAPIVersions(ch), false)
+	ch.Templates = append(ch.Templates, &chart.File{Name: "templates/api-versions", Data: []byte("{{ .Capabilities.APIVersions }}")})
+	is.Equal(chartNeedsAPIVersions(ch), true)
+}
+
 func TestGetVersionSet(t *testing.T) {
 	client := fakeclientset.NewSimpleClientset()
 

pkg/action/install.go

@@ -284,7 +284,7 @@ func (i *Install) RunWithContext(ctx context.Context, chrt *chart.Chart, vals ma
 	// the user doesn't have to specify both
 	i.Wait = i.Wait || i.Atomic
 
-	caps, err := i.cfg.getCapabilities()
+	caps, err := i.cfg.getCapabilities(chrt)
 	if err != nil {
 		return nil, err
 	}

pkg/action/uninstall.go

@@ -196,7 +196,7 @@ func joinErrors(errs []error) string {
 // deleteRelease deletes the release and returns list of delete resources and manifests that were kept in the deletion process
 func (u *Uninstall) deleteRelease(rel *release.Release) (kube.ResourceList, string, []error) {
 	var errs []error
-	caps, err := u.cfg.getCapabilities()
+	caps, err := u.cfg.getCapabilities(rel.Chart)
 	if err != nil {
 		return nil, rel.Manifest, []error{errors.Wrap(err, "could not get apiVersions from Kubernetes")}
 	}

pkg/action/upgrade.go

@@ -254,7 +254,7 @@ func (u *Upgrade) prepareUpgrade(name string, chart *chart.Chart, vals map[strin
 		IsUpgrade: true,
 	}
 
-	caps, err := u.cfg.getCapabilities()
+	caps, err := u.cfg.getCapabilities(chart)
 	if err != nil {
 		return nil, nil, err
 	}