RHTAP-6522: Add ChartFS.ExtractTo Method

internal/chartfs/chartfs.go

@@ -1,6 +1,8 @@
 package chartfs
 
 import (
+	"fmt"
+	"io"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -99,6 +101,65 @@ func (c *ChartFS) GetAllCharts() ([]chart.Chart, error) {
 	return charts, nil
 }
 
+func (c *ChartFS) extractChartDir(destDir, chartDir string) error {
+	return fs.WalkDir(c.fsys, chartDir, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return fmt.Errorf("walking %q: %w", path, err)
+		}
+		target := filepath.Join(destDir, path)
+		if d.IsDir() {
+			if err := os.MkdirAll(target, 0o755); err != nil {
+				return fmt.Errorf("creating directory %q: %w", target, err)
+			}
+			if err := os.Chmod(target, 0o755); err != nil {
+				return fmt.Errorf("setting directory permissions on %q: %w", target, err)
+			}
+			return nil
+		}
+		return c.extractFile(target, path)
+	})
+}
+
+func (c *ChartFS) extractFile(target, srcPath string) error {
+	if err := os.MkdirAll(filepath.Dir(target), 0o755); err != nil {
+		return fmt.Errorf("creating parent directory for %q: %w", target, err)
+	}
+	src, err := c.fsys.Open(srcPath)
+	if err != nil {
+		return fmt.Errorf("opening source %q: %w", srcPath, err)
+	}
+	defer src.Close()
+
+	dst, err := os.OpenFile(target, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0o644)
+	if err != nil {
+		return fmt.Errorf("creating file %q: %w", target, err)
+	}
+	defer dst.Close()
+
+	if _, err := io.Copy(dst, src); err != nil {
+		return fmt.Errorf("writing file %q: %w", target, err)
+	}
+	if err := os.Chmod(target, 0o644); err != nil {
+		return fmt.Errorf("setting file permissions on %q: %w", target, err)
+	}
+	return nil
+}
+
+// ExtractTo extracts all Helm chart directories from the embedded filesystem
+// to the destination directory on disk.
+func (c *ChartFS) ExtractTo(destDir string) error {
+	chartDirs, err := c.walkAndFindChartDirs(c.fsys, ".")
+	if err != nil {
+		return fmt.Errorf("discovering chart directories: %w", err)
+	}
+	for _, chartDir := range chartDirs {
+		if err := c.extractChartDir(destDir, chartDir); err != nil {
+			return fmt.Errorf("extracting chart %q: %w", chartDir, err)
+		}
+	}
+	return nil
+}
+
 // WithBaseDir returns a new ChartFS that is rooted at the given base directory.
 func (c *ChartFS) WithBaseDir(baseDir string) (*ChartFS, error) {
 	sub, err := fs.Sub(c.fsys, baseDir)

internal/chartfs/chartfs_test.go

@@ -2,6 +2,7 @@ package chartfs
 
 import (
 	"os"
+	"path/filepath"
 	"testing"
 
 	o "github.com/onsi/gomega"
@@ -45,3 +46,83 @@ func TestNewChartFS(t *testing.T) {
 		g.Expect(len(charts)).To(o.BeNumerically(">", 1))
 	})
 }
+
+func TestChartFS_ExtractTo(t *testing.T) {
+	g := o.NewWithT(t)
+
+	c := New(os.DirFS("../../test"))
+
+	destDir := t.TempDir()
+	err := c.ExtractTo(destDir)
+	g.Expect(err).To(o.Succeed())
+
+	t.Run("chart directories are extracted", func(t *testing.T) {
+		g := o.NewWithT(t)
+		expectedCharts := []string{
+			"charts/helmet-foundation",
+			"charts/helmet-infrastructure",
+			"charts/helmet-integrations",
+			"charts/helmet-networking",
+			"charts/helmet-operators",
+			"charts/helmet-product-a",
+			"charts/helmet-product-b",
+			"charts/helmet-product-c",
+			"charts/helmet-product-d",
+			"charts/helmet-storage",
+			"charts/testing",
+		}
+		for _, chartDir := range expectedCharts {
+			chartYaml := filepath.Join(destDir, chartDir, "Chart.yaml")
+			g.Expect(chartYaml).To(o.BeAnExistingFile())
+		}
+	})
+
+	t.Run("chart contents are correct", func(t *testing.T) {
+		g := o.NewWithT(t)
+		srcBytes, err := os.ReadFile("../../test/charts/helmet-product-a/Chart.yaml")
+		g.Expect(err).To(o.Succeed())
+
+		dstBytes, err := os.ReadFile(
+			filepath.Join(destDir, "charts/helmet-product-a/Chart.yaml"),
+		)
+		g.Expect(err).To(o.Succeed())
+		g.Expect(dstBytes).To(o.Equal(srcBytes))
+	})
+
+	t.Run("template files are extracted", func(t *testing.T) {
+		g := o.NewWithT(t)
+		notesPath := filepath.Join(
+			destDir, "charts/helmet-product-a/templates/NOTES.txt",
+		)
+		g.Expect(notesPath).To(o.BeAnExistingFile())
+	})
+
+	t.Run("non-chart files are excluded", func(t *testing.T) {
+		g := o.NewWithT(t)
+		g.Expect(filepath.Join(destDir, "values.yaml.tpl")).
+			ToNot(o.BeAnExistingFile())
+		g.Expect(filepath.Join(destDir, "config.yaml")).
+			ToNot(o.BeAnExistingFile())
+	})
+
+	t.Run("non-chart directories are excluded", func(t *testing.T) {
+		g := o.NewWithT(t)
+		g.Expect(filepath.Join(destDir, "charts/_common")).
+			ToNot(o.BeADirectory())
+	})
+
+	t.Run("file permissions are correct", func(t *testing.T) {
+		g := o.NewWithT(t)
+		chartYaml := filepath.Join(
+			destDir, "charts/helmet-product-a/Chart.yaml",
+		)
+		info, err := os.Stat(chartYaml)
+		g.Expect(err).To(o.Succeed())
+		g.Expect(info.Mode().Perm()).To(o.Equal(os.FileMode(0o644)))
+
+		chartDir := filepath.Join(destDir, "charts/helmet-product-a")
+		dirInfo, err := os.Stat(chartDir)
+		g.Expect(err).To(o.Succeed())
+		g.Expect(dirInfo.Mode().Perm()).To(o.Equal(os.FileMode(0o755)))
+	})
+}