ref: version refactored into action pattern

This adds an action implementation of 'helm version'. I'm testing out @adamreese's suggested function argument method of flexibly encapsulating logic in 'action' via function arguments.

Signed-off-by: Matt Butcher <matt.butcher@microsoft.com>

cmd/helm/version.go

@@ -19,12 +19,11 @@ package main
 import (
 	"fmt"
 	"io"
-	"text/template"
 
 	"github.com/spf13/cobra"
 
 	"k8s.io/helm/cmd/helm/require"
-	"k8s.io/helm/pkg/version"
+	"k8s.io/helm/pkg/action"
 )
 
 const versionDesc = `
@@ -66,21 +65,19 @@ func newVersionCmd(out io.Writer) *cobra.Command {
 }
 
 func (o *versionOptions) run(out io.Writer) error {
+
+	ver := &action.Version{}
+	if o.short {
+		ver.Formatter = action.ShortVersion()
+	}
 	if o.template != "" {
-		tt, err := template.New("_").Parse(o.template)
+		ver.Formatter = action.TemplateVersion(o.template)
+	}
+
+	result, err := ver.Run()
 	if err != nil {
 		return err
 	}
-		return tt.Execute(out, version.GetBuildInfo())
-	}
-	fmt.Fprintln(out, formatVersion(o.short))
+	fmt.Fprintln(out, result)
 	return nil
 }
-
-func formatVersion(short bool) string {
-	v := version.GetBuildInfo()
-	if short {
-		return fmt.Sprintf("%s+g%s", v.Version, v.GitCommit[:7])
-	}
-	return fmt.Sprintf("%#v", v)
-}

pkg/action/version.go

@@ -0,0 +1,73 @@
+/*
+Copyright The Helm Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package action
+
+import (
+	"bytes"
+	"fmt"
+	"text/template"
+
+	"k8s.io/helm/pkg/version"
+)
+
+// Version represents a Helm version action.
+type Version struct {
+	Formatter VersionFormatter
+}
+
+// VersionFormatter takes a version.BuildInfo and returns a printable string.
+type VersionFormatter func(info version.BuildInfo) (string, error)
+
+// Run retrieves the Helm version.
+func (v *Version) Run() (string, error) {
+	bi := version.GetBuildInfo()
+	if v.Formatter == nil {
+		v.Formatter = DefaultVersion()
+	}
+	return v.Formatter(bi)
+}
+
+// ShortVersion returns a VersionFormatter capable of generating a SemVer representation of the Helm version
+func ShortVersion() VersionFormatter {
+	return func(v version.BuildInfo) (string, error) {
+		commit := v.GitCommit
+		if len(commit) >= 7 {
+			commit = commit[:7]
+		}
+		return fmt.Sprintf("%s+g%s", v.Version, commit), nil
+	}
+}
+
+// TemplateVersion returns a VersionFormatter that uses a template to render the version
+func TemplateVersion(tpl string) VersionFormatter {
+	return func(v version.BuildInfo) (string, error) {
+		renderer, err := template.New("_").Parse(tpl)
+		if err != nil {
+			return "", err
+		}
+		var buf bytes.Buffer
+		err = renderer.Execute(&buf, v)
+		return buf.String(), err
+	}
+}
+
+// DefaultVersion returns a version formatted like kubectl formats its version.
+func DefaultVersion() VersionFormatter {
+	return func(v version.BuildInfo) (string, error) {
+		return fmt.Sprintf("%#v", v), nil
+	}
+}

pkg/action/version_test.go

@@ -0,0 +1,98 @@
+/*
+Copyright The Helm Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package action
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"k8s.io/helm/pkg/version"
+)
+
+func TestVersionFormatter(t *testing.T) {
+	var _ VersionFormatter = DefaultVersion()
+	var _ VersionFormatter = ShortVersion()
+	var _ VersionFormatter = TemplateVersion("")
+}
+
+func TestDefaultVersion(t *testing.T) {
+	golden := version.GetBuildInfo()
+	is := assert.New(t)
+	expect := fmt.Sprintf("%#v", golden)
+	result, err := DefaultVersion()(golden)
+	is.NoError(err)
+	is.Equal(expect, result)
+}
+
+func TestShortVersion(t *testing.T) {
+	v := version.GetBuildInfo()
+	v.GitCommit = "aaaaaaaaaaaaaaaa"
+	expect := fmt.Sprintf("%s+g%s", v.Version, v.GitCommit[:7])
+	is := assert.New(t)
+
+	got, err := ShortVersion()(v)
+	is.NoError(err)
+	is.Equal(expect, got)
+
+	// Make sure it handles the case where it can't get commit info
+	v.GitCommit = "test"
+	expect = fmt.Sprintf("%s+g%s", v.Version, v.GitCommit)
+	got, err = ShortVersion()(v)
+	is.NoError(err)
+	is.Equal(expect, got)
+}
+
+func TestTemplateVersion(t *testing.T) {
+	v := version.GetBuildInfo()
+	is := assert.New(t)
+	expect := fmt.Sprintf("foo-%s", v.GitCommit)
+
+	got, err := TemplateVersion("foo-{{.GitCommit}}")(v)
+	is.NoError(err)
+	is.Equal(expect, got)
+
+	// Test a broken template, too
+	_, err = TemplateVersion("foo-{{.GitCommit")(v)
+	is.Error(err)
+}
+
+func TestVersion(t *testing.T) {
+	// This test ensures that the default formatter works when none is specified
+	golden := version.GetBuildInfo()
+	is := assert.New(t)
+	expect := fmt.Sprintf("%#v", golden)
+
+	ver := new(Version)
+	got, err := ver.Run()
+	is.NoError(err)
+	is.Equal(expect, got)
+}
+
+func TestVersion_TemplateVersion(t *testing.T) {
+	// The purpose of this test is to ensure that we can override the formatter
+	v := version.GetBuildInfo()
+	is := assert.New(t)
+	expect := fmt.Sprintf("foo-%s", v.GitCommit)
+
+	ver := &Version{
+		Formatter: TemplateVersion("foo-{{.GitCommit}}"),
+	}
+	got, err := ver.Run()
+	is.NoError(err)
+	is.Equal(expect, got)
+}