Add --template and --templatefile options for more flexibility

Allow directly entered templates for scripting flexibility.
Changes --output=template to mean "string" and --output=templatefile
to mean "from file"

Author: smarterclayton

pkg/kubectl/cmd/get.go

@@ -26,7 +26,7 @@ import (
 
 func (f *Factory) NewCmdGet(out io.Writer) *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "get [(-o|--output=)console|json|yaml|...] <resource> [<id>]",
+		Use:   "get [(-o|--output=)json|yaml|...] <resource> [<id>]",
 		Short: "Display one or many resources",
 		Long: `Display one or many resources.
 
@@ -66,11 +66,9 @@ Examples:
 			checkErr(err)
 		},
 	}
-	// TODO Add an --output-version lock which can ensure that regardless of the
-	// server version, the client output stays the same.
-	cmd.Flags().StringP("output", "o", "console", "Output format: console|json|yaml|template")
-	cmd.Flags().Bool("no-headers", false, "When output format is console, don't print headers")
-	cmd.Flags().StringP("template", "t", "", "Path to template file to use when --output=template")
+	cmd.Flags().StringP("output", "o", "", "Output format: json|yaml|template|templatefile")
+	cmd.Flags().Bool("no-headers", false, "When using the default output, don't print headers")
+	cmd.Flags().StringP("template", "t", "", "Template string or path to template file to use when --output=template or --output=templatefile")
 	cmd.Flags().StringP("selector", "l", "", "Selector (label query) to filter on")
 	return cmd
 }

pkg/kubectl/resource_printer.go

@@ -55,6 +55,18 @@ func getPrinter(format, templateFile string, defaultPrinter ResourcePrinter) (Re
 	case "yaml":
 		printer = &YAMLPrinter{}
 	case "template":
+		var data []byte
+		if len(templateFile) == 0 {
+			return printer, fmt.Errorf("template format specified but no template given")
+		}
+		tmpl, err := template.New("output").Parse(templateFile)
+		if err != nil {
+			return printer, fmt.Errorf("Error parsing template %s, %v\n", string(data), err)
+		}
+		printer = &TemplatePrinter{
+			Template: tmpl,
+		}
+	case "templatefile":
 		var data []byte
 		if len(templateFile) > 0 {
 			var err error
@@ -63,7 +75,7 @@ func getPrinter(format, templateFile string, defaultPrinter ResourcePrinter) (Re
 				return printer, fmt.Errorf("Error reading template %s, %v\n", templateFile, err)
 			}
 		} else {
-			return printer, fmt.Errorf("template format specified but no template file given")
+			return printer, fmt.Errorf("templatefile format specified but no template file given")
 		}
 		tmpl, err := template.New("output").Parse(string(data))
 		if err != nil {

pkg/kubectl/resource_printer_test.go

@@ -52,6 +52,59 @@ func TestJSONPrinter(t *testing.T) {
 	testPrinter(t, &JSONPrinter{}, json.Unmarshal)
 }
 
+func TestPrintJSON(t *testing.T) {
+	buf := bytes.NewBuffer([]byte{})
+	if err := Print(buf, &api.Pod{ObjectMeta: api.ObjectMeta{Name: "foo"}}, "json", "", nil); err != nil {
+		t.Errorf("unexpected error: %#v", err)
+	}
+	obj := map[string]interface{}{}
+	if err := json.Unmarshal(buf.Bytes(), &obj); err != nil {
+		t.Errorf("unexpected error: %#v\n%s", err, buf.String())
+	}
+}
+
+func TestPrintYAML(t *testing.T) {
+	buf := bytes.NewBuffer([]byte{})
+	if err := Print(buf, &api.Pod{ObjectMeta: api.ObjectMeta{Name: "foo"}}, "yaml", "", nil); err != nil {
+		t.Errorf("unexpected error: %#v", err)
+	}
+	obj := map[string]interface{}{}
+	if err := yaml.Unmarshal(buf.Bytes(), &obj); err != nil {
+		t.Errorf("unexpected error: %#v\n%s", err, buf.String())
+	}
+}
+
+func TestPrintTemplate(t *testing.T) {
+	buf := bytes.NewBuffer([]byte{})
+	if err := Print(buf, &api.Pod{ObjectMeta: api.ObjectMeta{Name: "foo"}}, "template", "{{ .Name }}", nil); err != nil {
+		t.Errorf("unexpected error: %#v", err)
+	}
+	if buf.String() != "foo" {
+		t.Errorf("unexpected output: %s", buf.String())
+	}
+}
+
+func TestPrintEmptyTemplate(t *testing.T) {
+	buf := bytes.NewBuffer([]byte{})
+	if err := Print(buf, &api.Pod{ObjectMeta: api.ObjectMeta{Name: "foo"}}, "template", "", nil); err == nil {
+		t.Errorf("unexpected non-error")
+	}
+}
+
+func TestPrintBadTemplate(t *testing.T) {
+	buf := bytes.NewBuffer([]byte{})
+	if err := Print(buf, &api.Pod{ObjectMeta: api.ObjectMeta{Name: "foo"}}, "template", "{{ .Name", nil); err == nil {
+		t.Errorf("unexpected non-error")
+	}
+}
+
+func TestPrintBadTemplateFile(t *testing.T) {
+	buf := bytes.NewBuffer([]byte{})
+	if err := Print(buf, &api.Pod{ObjectMeta: api.ObjectMeta{Name: "foo"}}, "templatefile", "", nil); err == nil {
+		t.Errorf("unexpected non-error")
+	}
+}
+
 func testPrinter(t *testing.T, printer ResourcePrinter, unmarshalFunc func(data []byte, v interface{}) error) {
 	buf := bytes.NewBuffer([]byte{})