Print version information as JSON

cmd/version.go

@@ -1,20 +1,31 @@
 package cmd
 
 import (
+	"encoding/json"
 	"fmt"
 
 	"github.com/jongio/grut/internal/config"
 	"github.com/jongio/grut/internal/update"
 	"github.com/spf13/cobra"
 )
 
+type versionInfo struct {
+	Version string `json:"version"`
+}
+
 // newVersionCmd creates the version command.
 func newVersionCmd() *cobra.Command {
-	return &cobra.Command{
+	var jsonOutput bool
+	cmd := &cobra.Command{
 		Use:   cmdVersion,
 		Short: "Print the version of grut",
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Println(config.AppVersion)
+			if jsonOutput {
+				_ = json.NewEncoder(cmd.OutOrStdout()).Encode(versionInfo{Version: config.AppVersion})
+				return
+			}
+
+			fmt.Fprintln(cmd.OutOrStdout(), config.AppVersion)
 			// Show update notification inline.
 			if info := update.CheckForUpdate(config.AppVersion); info != nil {
 				fmt.Fprintf(cmd.ErrOrStderr(),
@@ -23,4 +34,6 @@ func newVersionCmd() *cobra.Command {
 			}
 		},
 	}
+	cmd.Flags().BoolVar(&jsonOutput, "json", false, "Print version information as JSON")
+	return cmd
 }

cmd/version_test.go

@@ -1,6 +1,8 @@
 package cmd
 
 import (
+	"bytes"
+	"encoding/json"
 	"testing"
 
 	"github.com/jongio/grut/internal/config"
@@ -13,17 +15,15 @@ import (
 // ---------------------------------------------------------------------------
 
 func TestVersionCmd_OutputContainsAppVersion(t *testing.T) {
-	// The version command uses fmt.Println which writes to os.Stdout, not
-	// cmd.OutOrStdout(). We verify it runs without error and check the
-	// version string is set correctly via the root command's Version field.
 	root, cleanup := buildRootCommand()
 	defer cleanup()
+	var out bytes.Buffer
+	root.SetOut(&out)
 	root.SetArgs([]string{"version"})
 
 	err := root.Execute()
 	require.NoError(t, err)
-	// The root command's Version field is what --version and the version
-	// subcommand use. Verify it's set correctly.
+	assert.Contains(t, out.String(), config.AppVersion)
 	assert.Equal(t, config.AppVersion, root.Version)
 }
 
@@ -43,6 +43,28 @@ func TestVersionCmd_StructureHasCorrectUse(t *testing.T) {
 	assert.Equal(t, "version", cmd.Use)
 }
 
+func TestVersionCmd_JSONOutput(t *testing.T) {
+	cmd := newVersionCmd()
+	var out bytes.Buffer
+	cmd.SetOut(&out)
+	cmd.SetArgs([]string{"--json"})
+
+	err := cmd.Execute()
+
+	require.NoError(t, err)
+	var got versionInfo
+	require.NoError(t, json.Unmarshal(out.Bytes(), &got))
+	assert.Equal(t, config.AppVersion, got.Version)
+}
+
+func TestVersionCmd_JSONFlagRegistered(t *testing.T) {
+	cmd := newVersionCmd()
+	flag := cmd.Flags().Lookup("json")
+	require.NotNil(t, flag)
+	assert.Equal(t, "bool", flag.Value.Type())
+	assert.Equal(t, "false", flag.DefValue)
+}
+
 func TestVersionCmd_HasRunNotRunE(t *testing.T) {
 	// version uses Run (not RunE) because it always succeeds.
 	cmd := newVersionCmd()

docs/version-json.md

@@ -0,0 +1,9 @@
+# Version JSON
+
+Use JSON output when scripts need the installed grut version:
+
+```bash
+grut version --json
+```
+
+The output contains a stable `version` field and does not include update notices.