go结构体组合

go没有继承。
类似于Java继承，SecurityGroup类继承了SecurityGroupRule列表类。

type SecurityGroup struct {
	Id string
	Name string
	Rules []SecurityGroupRule
}

type SecurityGroupRule struct {
	Id string
	SrcPort uint16
	DstPort uint16
}

go提倡组合，通过组合构建新的结构体，灵活度更高。

type SecurityGroup struct {
	Id   string
	Name string
}

type SecurityGroupRule struct {
	Id      string
	SrcPort uint16
	DstPort uint16
}

type SecurityGroupRules struct {
	Rules []SecurityGroupRule
}

type SecurityGroupAndRules struct {
	SecurityGroup
	SecurityGroupRules
}