feat(chartutil): add Save function

This replicates the previous Save function, which can save an
in-memory Chart proto to a tgz.

pkg/chartutil/save.go

+package chartutil
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/ghodss/yaml"
+	"github.com/kubernetes/helm/pkg/proto/hapi/chart"
+)
+
+var headerBytes = []byte("+aHR0cHM6Ly95b3V0dS5iZS96OVV6MWljandyTQo=")
+
+// Save creates an archived chart to the given directory.
+//
+// This takes an existing chart and a destination directory.
+//
+// If the directory is /foo, and the chart is named bar, with version 1.0.0, this
+// will generate /foo/bar-1.0.0.tgz.
+//
+// This returns the absolute path to the chart archive file.
+func Save(c *chart.Chart, outDir string) (string, error) {
+	// Create archive
+	if fi, err := os.Stat(outDir); err != nil {
+		return "", err
+	} else if !fi.IsDir() {
+		return "", fmt.Errorf("location %s is not a directory", outDir)
+	}
+
+	if c.Metadata == nil {
+		return "", errors.New("no Chart.yaml data")
+	}
+
+	cfile := c.Metadata
+	if cfile.Name == "" {
+		return "", errors.New("no chart name specified (Chart.yaml)")
+	} else if cfile.Version == "" {
+		return "", errors.New("no chart version specified (Chart.yaml)")
+	}
+
+	filename := fmt.Sprintf("%s-%s.tgz", cfile.Name, cfile.Version)
+	filename = filepath.Join(outDir, filename)
+	f, err := os.Create(filename)
+	if err != nil {
+		return "", err
+	}
+
+	// Wrap in gzip writer
+	zipper := gzip.NewWriter(f)
+	zipper.Header.Extra = headerBytes
+	zipper.Header.Comment = "Helm"
+
+	// Wrap in tar writer
+	twriter := tar.NewWriter(zipper)
+	rollback := false
+	defer func() {
+		twriter.Close()
+		zipper.Close()
+		f.Close()
+		if rollback {
+			os.Remove(filename)
+		}
+	}()
+
+	if err := writeTarContents(twriter, c, ""); err != nil {
+		rollback = true
+	}
+	return filename, err
+}
+
+func writeTarContents(out *tar.Writer, c *chart.Chart, prefix string) error {
+	base := filepath.Join(prefix, c.Metadata.Name)
+
+	// Save Chart.yaml
+	cdata, err := yaml.Marshal(c.Metadata)
+	if err != nil {
+		return err
+	}
+	if err := writeToTar(out, base+"/Chart.yaml", cdata); err != nil {
+		return err
+	}
+
+	// Save values.yaml
+	if c.Values != nil && len(c.Values.Raw) > 0 {
+		if err := writeToTar(out, base+"/values.yaml", []byte(c.Values.Raw)); err != nil {
+			return err
+		}
+	}
+
+	// Save templates
+	for _, f := range c.Templates {
+		n := filepath.Join(base, f.Name)
+		if err := writeToTar(out, n, f.Data); err != nil {
+			return err
+		}
+	}
+
+	// Save files
+	for _, f := range c.Files {
+		n := filepath.Join(base, f.TypeUrl)
+		if err := writeToTar(out, n, f.Value); err != nil {
+			return err
+		}
+	}
+
+	// Save dependencies
+	for _, dep := range c.Dependencies {
+		if err := writeTarContents(out, dep, base+"/charts"); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// writeToTar writes a single file to a tar archive.
+func writeToTar(out *tar.Writer, name string, body []byte) error {
+	// TODO: Do we need to create dummy parent directory names if none exist?
+	h := &tar.Header{
+		Name: name,
+		Mode: 0755,
+		Size: int64(len(body)),
+	}
+	if err := out.WriteHeader(h); err != nil {
+		return err
+	}
+	if _, err := out.Write(body); err != nil {
+		return err
+	}
+	return nil
+}

pkg/chartutil/save_test.go

+package chartutil
+
+import (
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/kubernetes/helm/pkg/proto/hapi/chart"
+)
+
+func TestSave(t *testing.T) {
+	tmp, err := ioutil.TempDir("", "helm-")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmp)
+
+	c := &chart.Chart{
+		Metadata: &chart.Metadata{
+			Name:    "ahab",
+			Version: "1.2.3.4",
+		},
+		Values: &chart.Config{
+			Raw: "ship: Pequod",
+		},
+	}
+
+	where, err := Save(c, tmp)
+	if err != nil {
+		t.Fatalf("Failed to save: %s", err)
+	}
+	if !strings.HasPrefix(where, tmp) {
+		t.Fatalf("Expected %q to start with %q", where, tmp)
+	}
+	if !strings.HasSuffix(where, ".tgz") {
+		t.Fatalf("Expected %q to end with .tgz", where)
+	}
+
+	c2, err := LoadFile(where)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if c2.Metadata.Name != c.Metadata.Name {
+		t.Fatalf("Expected chart archive to have %q, got %q", c.Metadata.Name, c2.Metadata.Name)
+	}
+	if c2.Values.Raw != c.Values.Raw {
+		t.Fatal("Values data did not match")
+	}
+}