feat(version): Add JSON/YAML output formats for version command (#709)

* feat(version): Add JSON/YAML output format for version command

 Fixes #513

* Loop for supported apis in template

CHANGELOG.adoc

@@ -18,6 +18,10 @@
 |===
 | | Description | PR
 
+| 🎁
+| Add JSON/YAML output format for version command
+| https://github.com/knative/client/pull/709[#709]
+
 | 🐣
 | Replaced `kn source cron` with `kn source ping`. `--schedule` is not mandatory anymore and defaults to "* * * * *" (every minute)
 | https://github.com/knative/client/issues/564[#564]

docs/cmd/kn_version.md

@@ -14,6 +14,7 @@ kn version [flags]
 
 ```
   -h, --help            help for version
+  -o, --output string   Output format. One of: json|yaml.
 ```
 
 ### Options inherited from parent commands

pkg/kn/commands/version/version.go

@@ -15,11 +15,13 @@
 package version
 
 import (
+	"encoding/json"
 	"fmt"
 
-	"knative.dev/client/pkg/kn/commands"
-
 	"github.com/spf13/cobra"
+	"sigs.k8s.io/yaml"
+
+	"knative.dev/client/pkg/kn/commands"
 )
 
 var Version string
@@ -38,12 +40,22 @@ var apiVersions = map[string][]string{
 	},
 }
 
+type knVersion struct {
+	Version       string
+	BuildDate     string
+	GitRevision   string
+	SupportedAPIs map[string][]string
+}
+
 // NewVersionCommand implements 'kn version' command
 func NewVersionCommand(p *commands.KnParams) *cobra.Command {
 	versionCmd := &cobra.Command{
 		Use:   "version",
 		Short: "Prints the client version",
-		Run: func(cmd *cobra.Command, args []string) {
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if cmd.Flags().Changed("output") {
+				return printVersionMachineReadable(cmd)
+			}
 			out := cmd.OutOrStdout()
 			fmt.Fprintf(out, "Version:      %s\n", Version)
 			fmt.Fprintf(out, "Build Date:   %s\n", BuildDate)
@@ -57,7 +69,37 @@ func NewVersionCommand(p *commands.KnParams) *cobra.Command {
 			for _, api := range apiVersions["eventing"] {
 				fmt.Fprintf(out, "  - %s\n", api)
 			}
+			return nil
 		},
 	}
+	versionCmd.Flags().StringP(
+		"output",
+		"o",
+		"",
+		"Output format. One of: json|yaml.",
+	)
 	return versionCmd
 }
+
+func printVersionMachineReadable(cmd *cobra.Command) error {
+	out := cmd.OutOrStdout()
+	v := knVersion{Version, BuildDate, GitRevision, apiVersions}
+	format := cmd.Flag("output").Value.String()
+	switch format {
+	case "JSON", "json":
+		b, err := json.MarshalIndent(v, "", "\t")
+		if err != nil {
+			return err
+		}
+		fmt.Fprint(out, string(b))
+	case "YAML", "yaml":
+		b, err := yaml.Marshal(v)
+		if err != nil {
+			return err
+		}
+		fmt.Fprint(out, string(b))
+	default:
+		return fmt.Errorf("Invalid value for output flag, choose one among 'json' or 'yaml'.")
+	}
+	return nil
+}

pkg/kn/commands/version/version_test.go

@@ -16,31 +16,25 @@ package version
 
 import (
 	"bytes"
+	"encoding/json"
 	"testing"
 	"text/template"
 
-	"knative.dev/client/pkg/kn/commands"
-
 	"github.com/spf13/cobra"
 	"gotest.tools/assert"
-)
+	"sigs.k8s.io/yaml"
 
-type versionOutput struct {
-	Version     string
-	BuildDate   string
-	GitRevision string
-}
+	"knative.dev/client/pkg/kn/commands"
+)
 
 var versionOutputTemplate = `Version:      {{.Version}}
 Build Date:   {{.BuildDate}}
 Git Revision: {{.GitRevision}}
 Supported APIs:
-* Serving
-  - serving.knative.dev/v1 (knative-serving v0.13.0)
-* Eventing
-  - sources.eventing.knative.dev/v1alpha1 (knative-eventing v0.13.1)
-  - sources.eventing.knative.dev/v1alpha2 (knative-eventing v0.13.1)
-  - eventing.knative.dev/v1alpha1 (knative-eventing v0.13.1)
+* Serving{{range $apis := .SupportedAPIs.serving }}
+  - {{$apis}}{{end}}
+* Eventing{{range $apis := .SupportedAPIs.eventing }}
+  - {{$apis}}{{end}}
 `
 
 const (
@@ -53,7 +47,8 @@ func TestVersion(t *testing.T) {
 	var (
 		versionCmd     *cobra.Command
 		knParams       *commands.KnParams
-		expectedVersionOutput string
+		expectedOutput string
+		knVersionObj   knVersion
 		output         *bytes.Buffer
 	)
 
@@ -61,43 +56,68 @@ func TestVersion(t *testing.T) {
 		Version = fakeVersion
 		BuildDate = fakeBuildDate
 		GitRevision = fakeGitRevision
-
-		expectedVersionOutput = genVersionOuput(t, versionOutputTemplate,
-			versionOutput{
-				fakeVersion,
-				fakeBuildDate,
-				fakeGitRevision})
-
+		knVersionObj = knVersion{fakeVersion, fakeBuildDate, fakeGitRevision, apiVersions}
+		expectedOutput = genVersionOuput(t, knVersionObj)
 		knParams = &commands.KnParams{}
 		versionCmd = NewVersionCommand(knParams)
 		output = new(bytes.Buffer)
 		versionCmd.SetOutput(output)
 	}
 
+	runVersionCmd := func(args []string) error {
+		setup()
+		versionCmd.SetArgs(args)
+		return versionCmd.Execute()
+	}
+
 	t.Run("creates a VersionCommand", func(t *testing.T) {
 		setup()
-
 		assert.Equal(t, versionCmd.Use, "version")
 		assert.Equal(t, versionCmd.Short, "Prints the client version")
-		assert.Assert(t, versionCmd.Run != nil)
+		assert.Assert(t, versionCmd.RunE != nil)
 	})
 
 	t.Run("prints version, build date, git revision, supported APIs", func(t *testing.T) {
-		setup()
+		err := runVersionCmd([]string{})
+		assert.NilError(t, err)
+		assert.Equal(t, output.String(), expectedOutput)
+	})
 
-		versionCmd.Run(versionCmd, []string{})
-		assert.Equal(t, output.String(), expectedVersionOutput)
+	t.Run("print version command with machine readable output", func(t *testing.T) {
+		t.Run("json", func(t *testing.T) {
+			err := runVersionCmd([]string{"-oJSON"})
+			assert.NilError(t, err)
+			in := knVersion{}
+			err = json.Unmarshal(output.Bytes(), &in)
+			assert.NilError(t, err)
+			assert.DeepEqual(t, in, knVersionObj)
+		})
+
+		t.Run("yaml", func(t *testing.T) {
+			err := runVersionCmd([]string{"-oyaml"})
+			assert.NilError(t, err)
+			jsonData, err := yaml.YAMLToJSON(output.Bytes())
+			assert.NilError(t, err)
+			in := knVersion{}
+			err = json.Unmarshal(jsonData, &in)
+			assert.NilError(t, err)
+			assert.DeepEqual(t, in, knVersionObj)
+		})
+
+		t.Run("invalid format", func(t *testing.T) {
+			err := runVersionCmd([]string{"-o", "jsonpath"})
+			assert.Assert(t, err != nil)
+			assert.ErrorContains(t, err, "Invalid", "output", "flag", "choose", "among")
+		})
 	})
 
 }
 
-func genVersionOuput(t *testing.T, templ string, vOutput versionOutput) string {
+func genVersionOuput(t *testing.T, obj knVersion) string {
 	tmpl, err := template.New("versionOutput").Parse(versionOutputTemplate)
 	assert.NilError(t, err)
-
 	buf := bytes.Buffer{}
-	err = tmpl.Execute(&buf, vOutput)
+	err = tmpl.Execute(&buf, obj)
 	assert.NilError(t, err)
-
 	return buf.String()
 }