Add ability to pass extra arguments to kustomize build command

chartify.go

@@ -56,6 +56,10 @@ type ChartifyOpts struct {
 	// EnableKustomizAlphaPlugins will add the `--enable_alpha_plugins` flag when running `kustomize build`
 	EnableKustomizeAlphaPlugins bool
 
+	// KustomizeBuildArgs are extra arguments to pass to `kustomize build` command
+	// For example, ["--enable-exec"] for plugins like ksops
+	KustomizeBuildArgs []string
+
 	Injectors []string
 	Injects   []string
 
@@ -279,6 +283,7 @@ func (r *Runner) Chartify(release, dirOrChart string, opts ...ChartifyOption) (s
 			Namespace:          u.Namespace,
 			HelmBinary:         r.helmBin(),
 			SortOptions:        u.SortOptions,
+			ExtraArgs:          u.KustomizeBuildArgs,
 		}
 		kustomizeFile, err := r.KustomizeBuild(dirOrChart, tempDir, kustomizeOpts)
 		if err != nil {
@@ -496,6 +501,7 @@ func (r *Runner) Chartify(release, dirOrChart string, opts ...ChartifyOption) (s
 			Transformers:          u.Transformers,
 			EnableAlphaPlugins:    u.EnableKustomizeAlphaPlugins,
 			SortOptions:           u.SortOptions,
+			ExtraArgs:             u.KustomizeBuildArgs,
 		}
 		if err := r.Patch(tempDir, generatedManifestFiles, patchOpts); err != nil {
 			return "", err

cmd/chartify/main.go

@@ -33,6 +33,7 @@ func main() {
 		Namespace:                   "",
 		ChartVersion:                "",
 		EnableKustomizeAlphaPlugins: false,
+		KustomizeBuildArgs:          nil,
 		Injectors:                   nil,
 		Injects:                     nil,
 		AdhocChartDependencies:      nil,
@@ -43,12 +44,14 @@ func main() {
 	}
 
 	deps := stringSlice{}
+	kustomizeBuildArgs := stringSlice{}
 
 	flag.StringVar(&file, "f", "-", "The path to the input file or stdout(-)")
 	flag.StringVar(&outDir, "o", "", "The path to the output directory")
 	flag.Var(&deps, "d", "one or more \"alias=chart:version\" to add adhoc chart dependencies")
 	flag.BoolVar(&opts.IncludeCRDs, "include-crds", false, "Whether to render CRDs contained in the chart and include the results into the output")
 	flag.StringVar(&strategicMergePatch, "strategic-merge-patch", "", "Path to a kustomize strategic merge patch file")
+	flag.Var(&kustomizeBuildArgs, "kustomize-build-arg", "Extra arguments to pass to 'kustomize build' command (e.g. --enable-exec). Can be specified multiple times.")
 
 	flag.Parse()
 
@@ -61,6 +64,7 @@ func main() {
 	}
 
 	opts.DeprecatedAdhocChartDependencies = deps
+	opts.KustomizeBuildArgs = kustomizeBuildArgs
 
 	c := chartify.New(chartify.HelmBin("helm"))
 

kustomize.go

@@ -80,6 +80,7 @@ type KustomizeBuildOpts struct {
 	Namespace          string
 	HelmBinary         string
 	SortOptions        *SortOptions
+	ExtraArgs          []string
 }
 
 func (o *KustomizeBuildOpts) SetKustomizeBuildOption(opts *KustomizeBuildOpts) error {
@@ -238,6 +239,11 @@ func (r *Runner) KustomizeBuild(srcDir string, tempDir string, opts ...Kustomize
 		kustomizeArgs = append(kustomizeArgs, "--helm-command="+u.HelmBinary)
 	}
 
+	// Add any extra arguments provided by the user
+	if len(u.ExtraArgs) > 0 {
+		kustomizeArgs = append(kustomizeArgs, u.ExtraArgs...)
+	}
+
 	out, err := r.runInDir(tempDir, bin, append(kustomizeArgs, tempDir)...)
 	if err != nil {
 		return "", err

kustomize_extra_args_test.go

@@ -0,0 +1,118 @@
+package chartify
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+type spyCall struct {
+	name string
+	args []string
+}
+
+// newSpyRunner returns a Runner whose RunCommand captures every invocation
+// instead of running a real process. The spy:
+//   - replies to `kustomize version` so kustomizeLoadRestrictionsNoneFlag /
+//     kustomizeEnableAlphaPluginsFlag can derive a flag, and
+//   - honors `--output <path>` (used by Patch) by writing a minimal resource
+//     YAML there, so callers that read the rendered file succeed.
+//
+// The kustomize binary name still has to resolve via exec.LookPath, so this
+// relies on kustomize being on PATH (already a documented test prerequisite).
+func newSpyRunner(t *testing.T, versionOut string) (*Runner, *[]spyCall) {
+	t.Helper()
+	var calls []spyCall
+	r := New()
+	r.RunCommand = func(name string, args []string, dir string, stdout, stderr io.Writer, env map[string]string) error {
+		calls = append(calls, spyCall{name: name, args: append([]string{}, args...)})
+
+		if len(args) > 0 && args[0] == "version" {
+			_, _ = io.WriteString(stdout, versionOut)
+			return nil
+		}
+		for i, a := range args {
+			if a == "--output" && i+1 < len(args) {
+				_ = os.WriteFile(args[i+1], []byte("kind: ConfigMap\nmetadata:\n  name: test\n"), 0644)
+			}
+		}
+		return nil
+	}
+	return r, &calls
+}
+
+// buildCall returns the first recorded invocation that runs a kustomize "build".
+func buildCall(calls []spyCall) (spyCall, bool) {
+	for _, c := range calls {
+		for _, a := range c.args {
+			if a == "build" {
+				return c, true
+			}
+		}
+	}
+	return spyCall{}, false
+}
+
+func TestKustomizeBuildExtraArgs(t *testing.T) {
+	r, callsPtr := newSpyRunner(t, "v5.0.0")
+
+	srcDir := t.TempDir()
+	tempDir := t.TempDir()
+
+	_, err := r.KustomizeBuild(srcDir, tempDir, &KustomizeBuildOpts{
+		ExtraArgs: []string{"--enable-exec"},
+	})
+	require.NoError(t, err)
+
+	build, ok := buildCall(*callsPtr)
+	require.True(t, ok, "expected a kustomize build invocation; calls=%v", *callsPtr)
+
+	// ExtraArgs must be appended to the build command.
+	require.Contains(t, build.args, "--enable-exec",
+		"ExtraArgs should be appended to the kustomize build command")
+	// Standard flags must still be present.
+	require.Contains(t, build.args, "--enable-helm")
+	require.Contains(t, build.args, "--load-restrictor=LoadRestrictionsNone")
+
+	// ExtraArgs must be inserted before the positional target (tempDir, passed
+	// last) so a flag is never mistaken for the build target.
+	require.NotEmpty(t, build.args)
+	require.Equal(t, tempDir, build.args[len(build.args)-1],
+		"the kustomize target must remain the last positional arg")
+}
+
+func TestKustomizeBuildNoExtraArgsByDefault(t *testing.T) {
+	r, callsPtr := newSpyRunner(t, "v5.0.0")
+
+	_, err := r.KustomizeBuild(t.TempDir(), t.TempDir())
+	require.NoError(t, err)
+
+	build, ok := buildCall(*callsPtr)
+	require.True(t, ok)
+	require.NotContains(t, build.args, "--enable-exec",
+		"no extra flags should be added when ExtraArgs is unset")
+}
+
+func TestPatchExtraArgs(t *testing.T) {
+	r, callsPtr := newSpyRunner(t, "v5.0.0")
+
+	tempDir := t.TempDir()
+	manifest := filepath.Join(tempDir, "templates", "cm.yaml")
+	require.NoError(t, os.MkdirAll(filepath.Dir(manifest), 0755))
+	require.NoError(t, os.WriteFile(manifest, []byte("kind: ConfigMap\nmetadata:\n  name: test\n"), 0644))
+
+	err := r.Patch(tempDir, []string{"templates/cm.yaml"}, &PatchOpts{
+		ExtraArgs: []string{"--enable-exec"},
+	})
+	require.NoError(t, err)
+
+	build, ok := buildCall(*callsPtr)
+	require.True(t, ok, "expected a kustomize build invocation; calls=%v", *callsPtr)
+	require.Contains(t, build.args, "--enable-exec",
+		"PatchOpts.ExtraArgs should be appended to the kustomize build command")
+	require.Equal(t, tempDir, build.args[len(build.args)-1],
+		"the kustomize target must remain the last positional arg")
+}

patch.go

@@ -25,6 +25,10 @@ type PatchOpts struct {
 
 	// SortOptions configures kustomize's sortOptions for resource ordering.
 	SortOptions *SortOptions
+
+	// ExtraArgs are extra arguments to pass to `kustomize build` command
+	// For example, ["--enable-exec"] for plugins like ksops
+	ExtraArgs []string
 }
 
 func (o *PatchOpts) SetPatchOption(opts *PatchOpts) error {
@@ -212,6 +216,11 @@ resources:
 		kustomizeArgs = append(kustomizeArgs, f)
 	}
 
+	// Add any extra arguments provided by the user
+	if len(u.ExtraArgs) > 0 {
+		kustomizeArgs = append(kustomizeArgs, u.ExtraArgs...)
+	}
+
 	// tempDir is the kustomize target, appended last (mirrors KustomizeBuild argument order).
 	_, err := r.run(nil, bin, append(kustomizeArgs, tempDir)...)
 	if err != nil {

tempdir_test.go

@@ -35,29 +35,29 @@ func TestGenerateID(t *testing.T) {
 		release: "foo",
 		chart:   "incubator/raw",
 		opts:    ChartifyOpts{},
-		want:    "foo-5586b9d54d",
+		want:    "foo-7bb8758c6f",
 	})
 
 	run(testcase{
 		release: "foo",
 		chart:   "stable/envoy",
 		opts:    ChartifyOpts{},
-		want:    "foo-748fb9844f",
+		want:    "foo-595bcf5dfd",
 	})
 
 	run(testcase{
 		release: "bar",
 		chart:   "incubator/raw",
 		opts:    ChartifyOpts{},
-		want:    "bar-77ddc8bd65",
+		want:    "bar-7759488ffd",
 	})
 
 	run(testcase{
 		release: "foo",
 		opts: ChartifyOpts{
 			Namespace: "myns",
 		},
-		want: "myns-foo-5dbbf694b5",
+		want: "myns-foo-54c5cbf858",
 	})
 
 	for id, n := range ids {