feat(show): add helm show schema cli command

Signed-off-by: Andrea Serrecchia <and.serrecchia@gmail.com>

pkg/action/show.go

@@ -40,6 +40,8 @@ const (
 	ShowChart ShowOutputFormat = "chart"
 	// ShowValues is the format which only shows the chart's values
 	ShowValues ShowOutputFormat = "values"
+	// ShowSchema is the format which only shows the chart's schema values
+	ShowSchema ShowOutputFormat = "schema"
 	// ShowReadme is the format which only shows the chart's README
 	ShowReadme ShowOutputFormat = "readme"
 	// ShowCRDs is the format which only shows the chart's CRDs
@@ -137,6 +139,12 @@ func (s *Show) Run(chartpath string) (string, error) {
 			}
 		}
 	}
+
+	if s.OutputFormat == ShowSchema {
+		if len(s.chart.Schema) != 0 {
+			fmt.Fprintf(&out, "%s\n", s.chart.Schema)
+		}
+	}
 	return out.String(), nil
 }
 

pkg/action/show_test.go

@@ -22,6 +22,23 @@ import (
 	chart "helm.sh/helm/v4/pkg/chart/v2"
 )
 
+var valuesSchema = `{
+			"$schema": "https://json-schema.org/draft-07/schema#",
+			"properties":{
+				"property1":{
+					"description": "desc1",
+					"properties":{
+						"subProp1":{"type": "string"},
+						"subProp2":{
+							"description": "desc2",
+							"type": "object"
+							}
+					},
+					"type": "object"
+				}
+			}
+	}`
+
 func TestShow(t *testing.T) {
 	config := actionConfigFixture(t)
 	client := NewShow(ShowAll, config)
@@ -96,6 +113,42 @@ func TestShowValuesByJsonPathFormat(t *testing.T) {
 	}
 }
 
+func TestShowNoSchema(t *testing.T) {
+	config := actionConfigFixture(t)
+	client := NewShow(ShowSchema, config)
+	client.chart = new(chart.Chart)
+	client.OutputFormat = ShowSchema
+	output, err := client.Run("")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(output) != 0 {
+		t.Errorf("expected empty values buffer, got %s", output)
+	}
+}
+
+func withSampleSchema() chartOption {
+	return func(opts *chartOptions) {
+		opts.Schema = []byte(valuesSchema)
+	}
+}
+
+func TestShowSchema(t *testing.T) {
+	config := actionConfigFixture(t)
+	client := NewShow(ShowSchema, config)
+	client.chart = buildChart(withSampleSchema())
+	output, err := client.Run("")
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Like other `helm show` commands, output ends with a trailing newline
+	expect := valuesSchema + "\n"
+	if output != expect {
+		t.Errorf("Expected\n%q\nGot\n%q\n", expect, output)
+	}
+}
+
 func TestShowCRDs(t *testing.T) {
 	config := actionConfigFixture(t)
 	client := NewShow(ShowCRDs, config)

pkg/cmd/show.go

@@ -42,6 +42,11 @@ This command inspects a chart (directory, file, or URL) and displays the content
 of the values.yaml file
 `
 
+const showSchemaDesc = `
+This command inspects a chart (directory, file, or URL) and displays the contents
+of the values.schema.json file
+`
+
 const showChartDesc = `
 This command inspects a chart (directory, file, or URL) and displays the contents
 of the Chart.yaml file
@@ -118,6 +123,27 @@ func newShowCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 		},
 	}
 
+	schemaSubCmd := &cobra.Command{
+		Use:               "schema [CHART]",
+		Short:             "show the chart's schema values",
+		Long:              showSchemaDesc,
+		Args:              require.ExactArgs(1),
+		ValidArgsFunction: validArgsFunc,
+		RunE: func(_ *cobra.Command, args []string) error {
+			client.OutputFormat = action.ShowSchema
+			err := addRegistryClient(client)
+			if err != nil {
+				return err
+			}
+			output, err := runShow(args, client)
+			if err != nil {
+				return err
+			}
+			fmt.Fprint(out, output)
+			return nil
+		},
+	}
+
 	chartSubCmd := &cobra.Command{
 		Use:               "chart [CHART]",
 		Short:             "show the chart's definition",
@@ -181,7 +207,7 @@ func newShowCmd(cfg *action.Configuration, out io.Writer) *cobra.Command {
 		},
 	}
 
-	cmds := []*cobra.Command{all, readmeSubCmd, valuesSubCmd, chartSubCmd, crdsSubCmd}
+	cmds := []*cobra.Command{all, readmeSubCmd, valuesSubCmd, schemaSubCmd, chartSubCmd, crdsSubCmd}
 	for _, subCmd := range cmds {
 		addShowFlags(subCmd, client)
 		showCommand.AddCommand(subCmd)

pkg/cmd/show_test.go

@@ -150,6 +150,10 @@ func TestShowValuesFileCompletion(t *testing.T) {
 	checkFileCompletion(t, "show values", true)
 }
 
+func TestShowSchemaFileCompletion(t *testing.T) {
+	checkFileCompletion(t, "show schema", true)
+}
+
 func TestShowCRDsFileCompletion(t *testing.T) {
 	checkFileCompletion(t, "show crds", true)
 }