Add ability to untar charts after downloading them

cmd/helm/fetch.go

@@ -13,8 +13,15 @@ import (
 	"github.com/spf13/cobra"
 )
 
+var untarFile bool
+
+// TODO(vaikas): Is there a well known directory for these??
+var untarDir string
+
 func init() {
 	RootCommand.AddCommand(fetchCmd)
+	fetchCmd.Flags().BoolVar(&untarFile, "untar", false, "If set to true, will untar the chart after downloading it.")
+	fetchCmd.Flags().StringVar(&untarDir, "untardir", ".", "If untar is specified, this flag specifies where to untar the chart.")
 }
 
 var fetchCmd = &cobra.Command{
@@ -49,10 +56,8 @@ func fetch(cmd *cobra.Command, args []string) error {
 	}
 
 	defer resp.Body.Close()
-	// TODO(vaikas): Implement untar / flag
-	untar := false
-	if untar {
-		return untarChart(resp.Body)
+	if untarFile {
+		return chart.Expand(untarDir, resp.Body)
 	}
 	p := strings.Split(u.String(), "/")
 	return saveChartFile(p[len(p)-1], resp.Body)
@@ -84,18 +89,6 @@ func mapRepoArg(arg string, r map[string]string) (*url.URL, error) {
 	return nil, fmt.Errorf("Invalid chart url format: %s", arg)
 }
 
-func untarChart(r io.Reader) error {
-	c, err := chart.LoadDataFromReader(r)
-	if err != nil {
-		return err
-	}
-	if c == nil {
-		return fmt.Errorf("Failed to untar the chart")
-	}
-	return fmt.Errorf("Not implemented yee")
-
-}
-
 func saveChartFile(c string, r io.Reader) error {
 	// Grab the chart name that we'll use for the name of the file to download to.
 	out, err := os.Create(c)

pkg/chart/chart.go

@@ -88,7 +88,7 @@ func (c *Chart) TemplatesDir() string {
 	return filepath.Join(c.loader.dir(), preTemplates)
 }
 
-// ChartsDir returns teh directory where dependency charts are stored.
+// ChartsDir returns the directory where dependency charts are stored.
 func (c *Chart) ChartsDir() string {
 	return filepath.Join(c.loader.dir(), preCharts)
 }
@@ -214,6 +214,44 @@ func Create(chartfile *Chartfile, dir string) (*Chart, error) {
 	}, nil
 }
 
+// Expand uncompresses and extracts a chart into the specified directory.
+func Expand(dir string, r io.Reader) error {
+	gr, err := gzip.NewReader(r)
+	if err != nil {
+		return err
+	}
+	defer gr.Close()
+	tr := tar.NewReader(gr)
+	for {
+		header, err := tr.Next()
+		if err == io.EOF {
+			break
+		} else if err != nil {
+			return err
+		}
+
+		path := filepath.Clean(filepath.Join(dir, header.Name))
+		info := header.FileInfo()
+		if info.IsDir() {
+			if err = os.MkdirAll(path, info.Mode()); err != nil {
+				return err
+			}
+			continue
+		}
+
+		file, err := os.OpenFile(path, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, info.Mode())
+		if err != nil {
+			return err
+		}
+		defer file.Close()
+		_, err = io.Copy(file, tr)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // fname prepares names for the filesystem
 func fname(name string) string {
 	// Right now, we don't do anything. Do we need to encode any particular

pkg/chart/chart_test.go

@@ -30,6 +30,7 @@ const (
 	testdir          = "testdata/frobnitz/"
 	testarchive      = "testdata/frobnitz-0.0.1.tgz"
 	testmember       = "templates/template.tpl"
+	expectedTemplate = "Hello {{.Name | default \"world\"}}\n"
 )
 
 // Type canaries. If these fail, they will fail at compile time.
@@ -270,3 +271,42 @@ func compareContent(filename string, content []byte) error {
 
 	return nil
 }
+
+func TestExpand(t *testing.T) {
+	r, err := os.Open(testarchive)
+	if err != nil {
+		t.Errorf("Failed to read testarchive file: %s", err)
+		return
+	}
+
+	td, err := ioutil.TempDir("", "helm-unittest-chart-")
+	if err != nil {
+		t.Errorf("Failed to create tempdir: %s", err)
+		return
+	}
+
+	err = Expand(td, r)
+	if err != nil {
+		t.Errorf("Failed to expand testarchive file: %s", err)
+	}
+
+	fi, err := os.Lstat(td + "/frobnitz/Chart.yaml")
+	if err != nil {
+		t.Errorf("Failed to stat Chart.yaml from expanded archive: %s", err)
+	}
+	if fi.Name() != "Chart.yaml" {
+		t.Errorf("Didn't get the right file name from stat, expected Chart.yaml, got: %s", fi.Name())
+	}
+
+	tr, err := os.Open(td + "/frobnitz/templates/template.tpl")
+	if err != nil {
+		t.Errorf("Failed to open template.tpl from expanded archive: %s", err)
+	}
+	c, err := ioutil.ReadAll(tr)
+	if err != nil {
+		t.Errorf("Failed to read contents of template.tpl from expanded archive: %s", err)
+	}
+	if string(c) != expectedTemplate {
+		t.Errorf("Contents of the expanded template differ, wanted '%s' got '%s'", expectedTemplate, c)
+	}
+}