(cli): Add group ls command

tools/asynq/cmd/group.go

@@ -0,0 +1,48 @@
+// Copyright 2022 Kentaro Hibino. All rights reserved.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
+package cmd
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	rootCmd.AddCommand(groupCmd)
+	groupCmd.AddCommand(groupListCmd)
+	groupListCmd.Flags().StringP("queue", "q", "", "queue to inspect")
+	groupListCmd.MarkFlagRequired("queue")
+}
+
+var groupCmd = &cobra.Command{
+	Use:   "group",
+	Short: "Manage groups",
+}
+
+var groupListCmd = &cobra.Command{
+	Use:   "ls",
+	Short: "List groups",
+	Args:  cobra.NoArgs,
+	Run:   groupLists,
+}
+
+func groupLists(cmd *cobra.Command, args []string) {
+	qname, err := cmd.Flags().GetString("queue")
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	inspector := createInspector()
+	groups, err := inspector.Groups(qname)
+	if len(groups) == 0 {
+		fmt.Printf("No groups found in queue %q\n", qname)
+		return
+	}
+	for _, g := range groups {
+		fmt.Println(g.Group)
+	}
+}