Add list flag to show available fields

Signed-off-by: Anders F Björklund <anders.f.bjorklund@gmail.com>

Author: afbjorklund

cmd/limactl/list.go

@@ -4,6 +4,8 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"reflect"
+	"strings"
 	"text/tabwriter"
 	"text/template"
 
@@ -13,6 +15,16 @@ import (
 	"github.com/spf13/cobra"
 )
 
+func instanceFields() []string {
+	fields := []string{}
+	var instance store.Instance
+	t := reflect.TypeOf(instance)
+	for i := 0; i < t.NumField(); i++ {
+		fields = append(fields, t.Field(i).Name)
+	}
+	return fields
+}
+
 func newListCommand() *cobra.Command {
 	listCommand := &cobra.Command{
 		Use:               "list",
@@ -24,6 +36,7 @@ func newListCommand() *cobra.Command {
 	}
 
 	listCommand.Flags().StringP("format", "f", "", "Format the output using the given Go template")
+	listCommand.Flags().Bool("list-fields", false, "List fields available for format")
 	listCommand.Flags().Bool("json", false, "JSONify output")
 	listCommand.Flags().BoolP("quiet", "q", false, "Only show names")
 
@@ -39,11 +52,25 @@ func listAction(cmd *cobra.Command, args []string) error {
 	if err != nil {
 		return err
 	}
+	listFields, err := cmd.Flags().GetBool("list-fields")
+	if err != nil {
+		return err
+	}
 	jsonFormat, err := cmd.Flags().GetBool("json")
 	if err != nil {
 		return err
 	}
 
+	if goFormat != "" && listFields {
+		return errors.New("option --format conflicts with --list-fields")
+	}
+	if jsonFormat && listFields {
+		return errors.New("option --json conflicts with --list-fields")
+	}
+	if listFields {
+		fmt.Println(strings.Join(instanceFields(), "\n"))
+		return nil
+	}
 	if quiet && jsonFormat {
 		return errors.New("option --quiet conflicts with --json")
 	}