feat(region): host list order by server count

cmd/climc/shell/compute/hosts.go

@@ -60,6 +60,8 @@ func init() {
 
 		Sn string `help:"find host by sn"`
 
+		OrderByServerCount string `help:"Order by server count" choices:"desc|asc"`
+
 		options.BaseListOptions
 	}
 	R(&HostListOptions{}, "host-list", "List hosts", func(s *mcclient.ClientSession, opts *HostListOptions) error {

pkg/apis/compute/host.go

@@ -124,6 +124,10 @@ type HostListInput struct {
 	ServerIdForNetwork string `json:"server_id_for_network"`
 	// 宿主机 cpu 架构
 	CpuArchitecture string `json:"cpu_architecture"`
+
+	// 按虚拟机数量排序
+	// enum: asc,desc
+	OrderByServerCount string `json:"order_by_server_count"`
 }
 
 type HostDetails struct {

pkg/compute/models/hosts.go

@@ -490,6 +490,17 @@ func (manager *SHostManager) OrderByExtraFields(
 	if err != nil {
 		return nil, errors.Wrap(err, "SZoneResourceBaseManager.OrderByExtraFields")
 	}
+
+	if db.NeedOrderQuery([]string{query.OrderByServerCount}) {
+		guests := GuestManager.Query().SubQuery()
+		guestCounts := guests.Query(
+			guests.Field("host_id"),
+			sqlchemy.COUNT("id").Label("guest_count"),
+		).GroupBy("host_id").SubQuery()
+		q = q.LeftJoin(guestCounts, sqlchemy.Equals(q.Field("id"), guestCounts.Field("host_id")))
+		db.OrderByFields(q, []string{query.OrderByServerCount}, []sqlchemy.IQueryField{guestCounts.Field("guest_count")})
+	}
+
 	return q, nil
 }