incus/cluster/group/list: Add support for column selection

Part of lxc#1027

Signed-off-by: HassanAlsamahi <hassanalsamahi12@gmail.com>

cmd/incus/cluster_group.go

@@ -22,6 +22,11 @@ type cmdClusterGroup struct {
 	cluster *cmdCluster
 }
 
+type clusterGroupColumn struct {
+	Name string
+	Data func(api.ClusterGroup) string
+}
+
 // Cluster management including assignment, creation, deletion, editing, listing, removal, renaming, and showing details.
 func (c *cmdClusterGroup) Command() *cobra.Command {
 	cmd := &cobra.Command{}
@@ -487,6 +492,47 @@ Pre-defined column shorthand chars:
 
 const defaultClusterGroupColumns = "ndm"
 
+func (c *cmdClusterGroupList) parseColumns() ([]clusterGroupColumn, error) {
+	columnsShorthandMap := map[rune]clusterGroupColumn{
+		'n': {i18n.G("NAME"), c.clusterGroupNameColumnData},
+		'm': {i18n.G("MEMBERS"), c.membersColumnData},
+		'd': {i18n.G("DESCRIPTION"), c.descriptionColumnData},
+	}
+
+	columnList := strings.Split(c.flagColumns, ",")
+
+	columns := []clusterGroupColumn{}
+
+	for _, columnEntry := range columnList {
+		if columnEntry == "" {
+			return nil, fmt.Errorf(i18n.G("Empty column entry (redundant, leading or trailing command) in '%s'"), c.flagColumns)
+		}
+
+		for _, columnRune := range columnEntry {
+			column, ok := columnsShorthandMap[columnRune]
+			if !ok {
+				return nil, fmt.Errorf(i18n.G("Unknown column shorthand char '%c' in '%s'"), columnRune, columnEntry)
+			}
+
+			columns = append(columns, column)
+		}
+	}
+
+	return columns, nil
+}
+
+func (c *cmdClusterGroupList) clusterGroupNameColumnData(group api.ClusterGroup) string {
+	return group.Name
+}
+
+func (c *cmdClusterGroupList) descriptionColumnData(group api.ClusterGroup) string {
+	return group.Description
+}
+
+func (c *cmdClusterGroupList) membersColumnData(group api.ClusterGroup) string {
+	return fmt.Sprintf("%d", len(group.Members))
+}
+
 // Run executes the command to list all the cluster groups, their descriptions, and number of members.
 func (c *cmdClusterGroupList) Run(cmd *cobra.Command, args []string) error {
 	// Quick checks.
@@ -523,19 +569,28 @@ func (c *cmdClusterGroupList) Run(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	// Parse column flags.
+	columns, err := c.parseColumns()
+	if err != nil {
+		return err
+	}
+
 	// Render the table
 	data := [][]string{}
 	for _, group := range groups {
-		line := []string{group.Name, group.Description, fmt.Sprintf("%d", len(group.Members))}
+		line := []string{}
+		for _, column := range columns {
+			line = append(line, column.Data(group))
+		}
+
 		data = append(data, line)
 	}
 
 	sort.Sort(cli.SortColumnsNaturally(data))
 
-	header := []string{
-		i18n.G("NAME"),
-		i18n.G("DESCRIPTION"),
-		i18n.G("MEMBERS"),
+	header := []string{}
+	for _, column := range columns {
+		header = append(header, column.Name)
 	}
 
 	return cli.RenderTable(c.flagFormat, header, data, groups)