feat(*): add --quiet flag to 'helm lint'

Quiet flag reduce the verbosity, such that the only text
that is written to the console is lint warnings/errors

Closes #9994

Signed-off-by: Piotr Resztak <piotr.resztak@gmail.com>

cmd/helm/lint.go

@@ -29,6 +29,7 @@ import (
 	"helm.sh/helm/v3/pkg/action"
 	"helm.sh/helm/v3/pkg/cli/values"
 	"helm.sh/helm/v3/pkg/getter"
+	"helm.sh/helm/v3/pkg/lint/support"
 )
 
 var longLintHelp = `
@@ -76,12 +77,23 @@ func newLintCmd(out io.Writer) *cobra.Command {
 
 			var message strings.Builder
 			failed := 0
+			errorsOrWarnings := 0
 
 			for _, path := range paths {
-				fmt.Fprintf(&message, "==> Linting %s\n", path)
-
 				result := client.Run([]string{path}, vals)
 
+				// If there is no errors/warnings and quiet flag is set
+				// go to the next chart
+				hasWarningsOrErrors := action.HasWarningsOrErrors(result)
+				if hasWarningsOrErrors {
+					errorsOrWarnings++
+				}
+				if client.Quiet && !hasWarningsOrErrors {
+					continue
+				}
+
+				fmt.Fprintf(&message, "==> Linting %s\n", path)
+
 				// All the Errors that are generated by a chart
 				// that failed a lint will be included in the
 				// results.Messages so we only need to print
@@ -93,7 +105,9 @@ func newLintCmd(out io.Writer) *cobra.Command {
 				}
 
 				for _, msg := range result.Messages {
-					fmt.Fprintf(&message, "%s\n", msg)
+					if !client.Quiet || msg.Severity > support.InfoSev {
+						fmt.Fprintf(&message, "%s\n", msg)
+					}
 				}
 
 				if len(result.Errors) != 0 {
@@ -112,14 +126,17 @@ func newLintCmd(out io.Writer) *cobra.Command {
 			if failed > 0 {
 				return errors.New(summary)
 			}
-			fmt.Fprintln(out, summary)
+			if !client.Quiet || errorsOrWarnings > 0 {
+				fmt.Fprintln(out, summary)
+			}
 			return nil
 		},
 	}
 
 	f := cmd.Flags()
 	f.BoolVar(&client.Strict, "strict", false, "fail on lint warnings")
 	f.BoolVar(&client.WithSubcharts, "with-subcharts", false, "lint dependent charts")
+	f.BoolVar(&client.Quiet, "quiet", false, "print only warnings and errors")
 	addValueOptionsFlags(f, valueOpts)
 
 	return cmd

cmd/helm/lint_test.go

@@ -37,6 +37,27 @@ func TestLintCmdWithSubchartsFlag(t *testing.T) {
 	runTestCmd(t, tests)
 }
 
+func TestLintCmdWithQuietFlag(t *testing.T) {
+	testChart1 := "testdata/testcharts/alpine"
+	testChart2 := "testdata/testcharts/chart-bad-requirements"
+	tests := []cmdTestCase{{
+		name:   "lint good chart using --quiet flag",
+		cmd:    fmt.Sprintf("lint --quiet %s", testChart1),
+		golden: "output/lint-quiet.txt",
+	}, {
+		name:      "lint two charts, one with error using --quiet flag",
+		cmd:       fmt.Sprintf("lint --quiet %s %s", testChart1, testChart2),
+		golden:    "output/lint-quiet-with-error.txt",
+		wantError: true,
+	}, {
+		name:   "lint chart with warning using --quiet flag",
+		cmd:    "lint --quiet testdata/testcharts/chart-with-only-crds",
+		golden: "output/lint-quiet-with-warning.txt",
+	}}
+	runTestCmd(t, tests)
+
+}
+
 func TestLintFileCompletion(t *testing.T) {
 	checkFileCompletion(t, "lint", true)
 	checkFileCompletion(t, "lint mypath", true) // Multiple paths can be given

cmd/helm/testdata/output/lint-quiet-with-error.txt

@@ -0,0 +1,8 @@
+==> Linting testdata/testcharts/chart-bad-requirements
+[ERROR] Chart.yaml: unable to parse YAML
+	error converting YAML to JSON: yaml: line 6: did not find expected '-' indicator
+[WARNING] templates/: directory not found
+[ERROR] : unable to load chart
+	cannot load Chart.yaml: error converting YAML to JSON: yaml: line 6: did not find expected '-' indicator
+
+Error: 2 chart(s) linted, 1 chart(s) failed

cmd/helm/testdata/output/lint-quiet-with-warning.txt

@@ -0,0 +1,4 @@
+==> Linting testdata/testcharts/chart-with-only-crds
+[WARNING] templates/: directory not found
+
+1 chart(s) linted, 0 chart(s) failed

pkg/action/lint.go

@@ -36,6 +36,7 @@ type Lint struct {
 	Strict        bool
 	Namespace     string
 	WithSubcharts bool
+	Quiet         bool
 }
 
 // LintResult is the result of Lint
@@ -75,6 +76,16 @@ func (l *Lint) Run(paths []string, vals map[string]interface{}) *LintResult {
 	return result
 }
 
+// HasWaringsOrErrors checks is LintResult has any warnings or errors
+func HasWarningsOrErrors(result *LintResult) bool {
+	for _, msg := range result.Messages {
+		if msg.Severity > support.InfoSev {
+			return true
+		}
+	}
+	return false
+}
+
 func lintChart(path string, vals map[string]interface{}, namespace string, strict bool) (support.Linter, error) {
 	var chartPath string
 	linter := support.Linter{}