Add JSON output format for CLI commands

internal/cli/version.go

@@ -2,6 +2,7 @@ package cli
 
 import (
 	"context"
+	"flag"
 	"fmt"
 	"io"
 
@@ -13,16 +14,44 @@ func versionCommand(_ context.Context, args []string, stdout, stderr io.Writer)
 		printVersionHelp(stdout)
 		return exitOK
 	}
-	if rejectExtraArgs(stderr, "version", args) {
+	flags := flag.NewFlagSet("version", flag.ContinueOnError)
+	flags.SetOutput(stderr)
+	formatFlag := addFormatFlag(flags)
+	if err := flags.Parse(args); err != nil {
 		return exitUsage
 	}
+	if rejectExtraArgs(stderr, "version", flags.Args()) {
+		return exitUsage
+	}
+	format, ok := parseOutputFormat(stderr, "version", *formatFlag)
+	if !ok {
+		return exitUsage
+	}
+	if app.IsJSONOutput(format) {
+		err := app.WriteJSONEnvelope(stdout, "version", true, nil, versionResult{
+			Application: app.Name,
+			Version:     app.Version,
+		}, nil)
+		if err != nil {
+			return fail(stderr, err)
+		}
+		return exitOK
+	}
 	fmt.Fprintln(stdout, app.VersionString())
 	return exitOK
 }
 
+type versionResult struct {
+	Application string `json:"application"`
+	Version     string `json:"version"`
+}
+
 func printVersionHelp(w io.Writer) {
 	fmt.Fprint(w, `Usage:
-  distributor version
+  distributor version [--format text|json]
+
+Options:
+  --format text|json  Output format
 
 Print version information.
 `)