feat: add chart validation utilities

pkg/lint/chart_validator.go

@@ -0,0 +1,202 @@
+package lint
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// ChartValidator provides utilities for validating Helm charts.
+type ChartValidator struct {
+_chartPath string
+}
+
+// NewChartValidator creates a new chart validator.
+func NewChartValidator(chartPath string) *ChartValidator {
+	return &ChartValidator{_chartPath: chartPath}
+}
+
+// ValidationResult contains the result of a validation check.
+type ValidationResult struct {
+	Passed  bool
+	Message string
+	Details string
+}
+
+// ValidateChart performs comprehensive validation of a Helm chart.
+func (v *ChartValidator) ValidateChart() []ValidationResult {
+	var results []ValidationResult
+
+	results = append(results, v.ValidateChartYAML())
+	results = append(results, v.ValidateTemplates())
+	results = append(results, v.ValidateValues())
+	results = append(results, v.ValidateDependencies())
+	results = append(results, v.ValidateMetadata())
+
+	return results
+}
+
+// ValidateChartYAML validates Chart.yaml structure.
+func (v *ChartValidator) ValidateChartYAML() ValidationResult {
+	chartYAML := filepath.Join(v._chartPath, "Chart.yaml")
+	if _, err := os.Stat(chartYAML); os.IsNotExist(err) {
+		return ValidationResult{
+			Passed:  false,
+			Message: "Chart.yaml not found",
+			Details: "Every Helm chart must have a Chart.yaml file",
+		}
+	}
+
+	content, err := os.ReadFile(chartYAML)
+	if err != nil {
+		return ValidationResult{
+			Passed:  false,
+			Message: "Failed to read Chart.yaml",
+			Details: err.Error(),
+		}
+	}
+
+	contentStr := string(content)
+	requiredFields := []string{"apiVersion", "name", "version"}
+	for _, field := range requiredFields {
+		if !strings.Contains(contentStr, field+":") {
+			return ValidationResult{
+				Passed:  false,
+				Message: fmt.Sprintf("Missing required field: %s", field),
+				Details: fmt.Sprintf("Chart.yaml must contain '%s' field", field),
+			}
+		}
+	}
+
+	return ValidationResult{
+		Passed:  true,
+		Message: "Chart.yaml is valid",
+	}
+}
+
+// ValidateTemplates validates templates directory.
+func (v *ChartValidator) ValidateTemplates() ValidationResult {
+	templatesDir := filepath.Join(v._chartPath, "templates")
+	if _, err := os.Stat(templatesDir); os.IsNotExist(err) {
+		return ValidationResult{
+			Passed:  false,
+			Message: "Templates directory not found",
+			Details: "Charts should have a templates directory",
+		}
+	}
+
+	var files []string
+	filepath.Walk(templatesDir, func(path string, info os.FileInfo, err error) error {
+		if !info.IsDir() {
+			files = append(files, path)
+		}
+		return nil
+	})
+
+	if len(files) == 0 {
+		return ValidationResult{
+			Passed:  false,
+			Message: "No template files found",
+			Details: "Templates directory is empty",
+		}
+	}
+
+	return ValidationResult{
+		Passed:  true,
+		Message: fmt.Sprintf("Found %d template files", len(files)),
+	}
+}
+
+// ValidateValues validates values.yaml.
+func (v *ChartValidator) ValidateValues() ValidationResult {
+	valuesYAML := filepath.Join(v._chartPath, "values.yaml")
+	if _, err := os.Stat(valuesYAML); os.IsNotExist(err) {
+		return ValidationResult{
+			Passed:  false,
+			Message: "values.yaml not found",
+			Details: "Charts should have a values.yaml file",
+		}
+	}
+
+	return ValidationResult{
+		Passed:  true,
+		Message: "values.yaml exists",
+	}
+}
+
+// ValidateDependencies validates chart dependencies.
+func (v *ChartValidator) ValidateDependencies() ValidationResult {
+	chartYAML := filepath.Join(v._chartPath, "Chart.yaml")
+	content, err := os.ReadFile(chartYAML)
+	if err != nil {
+		return ValidationResult{
+			Passed:  true,
+			Message: "Could not check dependencies",
+		}
+	}
+
+	contentStr := string(content)
+	if strings.Contains(contentStr, "dependencies:") {
+		return ValidationResult{
+			Passed:  true,
+			Message: "Chart has dependencies defined",
+		}
+	}
+
+	return ValidationResult{
+		Passed:  true,
+		Message: "No dependencies (optional)",
+	}
+}
+
+// ValidateMetadata validates chart metadata.
+func (v *ChartValidator) ValidateMetadata() ValidationResult {
+	chartYAML := filepath.Join(v._chartPath, "Chart.yaml")
+	content, err := os.ReadFile(chartYAML)
+	if err != nil {
+		return ValidationResult{
+			Passed:  true,
+			Message: "Could not check metadata",
+		}
+	}
+
+	contentStr := string(content)
+	optionalFields := []string{"description", "maintainers", "home", "sources"}
+	found := 0
+	for _, field := range optionalFields {
+		if strings.Contains(contentStr, field+":") {
+			found++
+		}
+	}
+
+	return ValidationResult{
+		Passed:  true,
+		Message: fmt.Sprintf("Found %d/%d optional metadata fields", found, len(optionalFields)),
+	}
+}
+
+// PrintReport prints a formatted validation report.
+func PrintReport(results []ValidationResult) string {
+	report := "Helm Chart Validation Report\n"
+	report += "===========================\n\n"
+
+	passed := 0
+	failed := 0
+	for _, r := range results {
+		status := "PASS"
+		if !r.Passed {
+			status = "FAIL"
+			failed++
+		} else {
+			passed++
+		}
+		report += fmt.Sprintf("[%s] %s\n", status, r.Message)
+		if r.Details != "" {
+			report += fmt.Sprintf("       %s\n", r.Details)
+		}
+	}
+
+	report += fmt.Sprintf("\nResults: %d passed, %d failed\n", passed, failed)
+	return report
+}