Add --helm-debug Flag to Kustomize for Enhanced Helm Debugging (#5751)

* feat: add helm-debug flag

* revert: go.work.sum

* test: add helm chart args helm-debug test

* test: helm debug flag

* refactor: helm debug output

* style: linting

* revert: go.work.sum

api/internal/builtins/HelmChartInflationGenerator.go

@@ -10,6 +10,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"regexp"
+	"slices"
 	"strings"
 
 	"sigs.k8s.io/kustomize/api/resmap"
@@ -62,6 +63,9 @@ func (p *HelmChartInflationGeneratorPlugin) Config(
 	if len(h.GeneralConfig().HelmConfig.ApiVersions) != 0 {
 		p.HelmChart.ApiVersions = h.GeneralConfig().HelmConfig.ApiVersions
 	}
+	if h.GeneralConfig().HelmConfig.Debug {
+		p.HelmChart.Debug = h.GeneralConfig().HelmConfig.Debug
+	}
 
 	p.h = h
 	if err = yaml.Unmarshal(config, p); err != nil {
@@ -168,13 +172,17 @@ func (p *HelmChartInflationGeneratorPlugin) runHelmCommand(
 		fmt.Sprintf("HELM_DATA_HOME=%s/.data", p.ConfigHome)}
 	cmd.Env = append(os.Environ(), env...)
 	err := cmd.Run()
+	errorOutput := stderr.String()
+	if slices.Contains(args, "--debug") {
+		errorOutput = " Helm stack trace:\n" + errorOutput + "\nHelm template:\n" + stdout.String() + "\n"
+	}
 	if err != nil {
 		helm := p.h.GeneralConfig().HelmConfig.Command
 		err = errors.WrapPrefixf(
 			fmt.Errorf(
 				"unable to run: '%s %s' with env=%s (is '%s' installed?): %w",
 				helm, strings.Join(args, " "), env, helm, err),
-			stderr.String(),
+			errorOutput,
 		)
 	}
 	return stdout.Bytes(), err

api/types/helmchartargs.go

@@ -96,6 +96,9 @@ type HelmChart struct {
 
 	// SkipTests skips tests from templated output.
 	SkipTests bool `json:"skipTests,omitempty" yaml:"skipTests,omitempty"`
+
+	// debug enables debug output from the Helm chart inflator generator.
+	Debug bool `json:"debug,omitempty" yaml:"debug,omitempty"`
 }
 
 // HelmChartArgs contains arguments to helm.
@@ -188,5 +191,8 @@ func (h HelmChart) AsHelmArgs(absChartHome string) []string {
 	if h.SkipHooks {
 		args = append(args, "--no-hooks")
 	}
+	if h.Debug {
+		args = append(args, "--debug")
+	}
 	return args
 }

api/types/helmchartargs_test.go

@@ -60,4 +60,21 @@ func TestAsHelmArgs(t *testing.T) {
 				"-f", "values1", "-f", "values2",
 				"--api-versions", "foo", "--api-versions", "bar"})
 	})
+
+	t.Run("use helm-debug", func(t *testing.T) {
+		p := types.HelmChart{
+			Name:                  "chart-name",
+			Version:               "1.0.0",
+			Repo:                  "https://helm.releases.hashicorp.com",
+			ValuesFile:            "values",
+			AdditionalValuesFiles: []string{"values1", "values2"},
+			Debug:                 true,
+		}
+		require.Equal(t, p.AsHelmArgs("/home/charts"),
+			[]string{"template", "--generate-name", "/home/charts/chart-name",
+				"-f", "values",
+				"-f", "values1",
+				"-f", "values2",
+				"--debug"})
+	})
 }

api/types/pluginconfig.go

@@ -8,6 +8,7 @@ type HelmConfig struct {
 	Command     string
 	ApiVersions []string
 	KubeVersion string
+	Debug       bool
 }
 
 // PluginConfig holds plugin configuration.

kustomize/commands/build/build.go

@@ -30,6 +30,7 @@ var theFlags struct {
 	helmCommand     string
 	helmApiVersions []string
 	helmKubeVersion string
+	helmDebug       bool
 	loadRestrictor  string
 	reorderOutput   string
 	fnOptions       types.FnPluginLoadingOptions
@@ -163,6 +164,7 @@ func HonorKustomizeFlags(kOpts *krusty.Options, flags *flag.FlagSet) *krusty.Opt
 	kOpts.PluginConfig.HelmConfig.Command = theFlags.helmCommand
 	kOpts.PluginConfig.HelmConfig.ApiVersions = theFlags.helmApiVersions
 	kOpts.PluginConfig.HelmConfig.KubeVersion = theFlags.helmKubeVersion
+	kOpts.PluginConfig.HelmConfig.Debug = theFlags.helmDebug
 	kOpts.AddManagedbyLabel = isManagedByLabelEnabled()
 	return kOpts
 }

kustomize/commands/build/flagenablehelm.go

@@ -31,4 +31,9 @@ func AddFlagEnableHelm(set *pflag.FlagSet) {
 		"helm-kube-version",
 		"", // default
 		"Kubernetes version used by Helm for Capabilities.KubeVersion")
+	set.BoolVar(
+		&theFlags.helmDebug,
+		"helm-debug",
+		false,
+		"Enable debug output from the Helm chart inflator generator.")
 }

plugin/builtin/helmchartinflationgenerator/HelmChartInflationGenerator.go

@@ -14,6 +14,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"regexp"
+	"slices"
 	"strings"
 
 	"sigs.k8s.io/kustomize/api/resmap"
@@ -68,6 +69,9 @@ func (p *plugin) Config(
 	if len(h.GeneralConfig().HelmConfig.ApiVersions) != 0 {
 		p.HelmChart.ApiVersions = h.GeneralConfig().HelmConfig.ApiVersions
 	}
+	if h.GeneralConfig().HelmConfig.Debug {
+		p.HelmChart.Debug = h.GeneralConfig().HelmConfig.Debug
+	}
 
 	p.h = h
 	if err = yaml.Unmarshal(config, p); err != nil {
@@ -174,13 +178,17 @@ func (p *plugin) runHelmCommand(
 		fmt.Sprintf("HELM_DATA_HOME=%s/.data", p.ConfigHome)}
 	cmd.Env = append(os.Environ(), env...)
 	err := cmd.Run()
+	errorOutput := stderr.String()
+	if slices.Contains(args, "--debug") {
+		errorOutput = " Helm stack trace:\n" + errorOutput + "\nHelm template:\n" + stdout.String() + "\n"
+	}
 	if err != nil {
 		helm := p.h.GeneralConfig().HelmConfig.Command
 		err = errors.WrapPrefixf(
 			fmt.Errorf(
 				"unable to run: '%s %s' with env=%s (is '%s' installed?): %w",
 				helm, strings.Join(args, " "), env, helm, err),
-			stderr.String(),
+			errorOutput,
 		)
 	}
 	return stdout.Bytes(), err

plugin/builtin/helmchartinflationgenerator/HelmChartInflationGenerator_test.go

@@ -959,3 +959,37 @@ chartHome: ./charts
 	assert.Contains(t, string(chartYamlContent), "name: test-chart")
 	assert.Contains(t, string(chartYamlContent), "version: 1.0.0")
 }
+
+func TestHelmChartInflationGeneratorWithDebug(t *testing.T) {
+	th := kusttest_test.MakeEnhancedHarnessWithTmpRoot(t).
+		PrepBuiltin("HelmChartInflationGenerator")
+	defer th.Reset()
+	if err := th.ErrIfNoHelm(); err != nil {
+		t.Skip("skipping: " + err.Error())
+	}
+	copyTestChartsIntoHarness(t, th)
+
+	rm := th.LoadAndRunGenerator(`
+apiVersion: builtin
+kind: HelmChartInflationGenerator
+metadata:
+  name: test-chart
+name: test-chart
+version: 1.0.0
+releaseName: test
+chartHome: ./charts
+debug: true
+`)
+
+	cm, err := rm.Resources()[0].GetFieldValue("metadata.name")
+	require.NoError(t, err)
+	assert.Equal(t, "bar", cm)
+
+	chartDir := filepath.Join(th.GetRoot(), "charts/test-chart")
+	assert.True(t, th.GetFSys().Exists(chartDir))
+
+	chartYamlContent, err := th.GetFSys().ReadFile(filepath.Join(chartDir, "Chart.yaml"))
+	require.NoError(t, err)
+	assert.Contains(t, string(chartYamlContent), "name: test-chart")
+	assert.Contains(t, string(chartYamlContent), "version: 1.0.0")
+}