CloudFormation - 可以嵌套映射吗？

Question

是否可以在CloudFormation中使用嵌套映射,如下例所示？

"Mappings" :  
{
    "Regions" : 
    {
        "us-east-1" : 
        {
            "Environments" :
            {
                "dev" : 
                {
                    "ImageId" : "something",
                    "Subnet" : "something"
                },
                "qa" :
                {
                    "ImageId" : "something",
                    "Subnet" : "something"
                }
            }
        },
        "us-west-2" : 
        {
            "Environments" :
            {
                "dev" : 
                {
                    "ImageId" : "something",
                    "Subnet" : "something"
                },
                "qa" :
                {
                    "ImageId" : "something",
                    "Subnet" : "something"
                }
            }
        }
    }
}

当我尝试做这样的事情时,我收到以下错误:

模板格式错误:每个Mappings属性必须是String或List.

如果无法嵌套映射,那么在CFT中存储需要两个参数选择的值的最佳方法是什么(例如依赖于BOTH Region和environment的值)？

Answer 1

我最终这样做:

"Mappings" :  
{
    "dev" : 
    {
        "us-east-1" :
        {
            "ImageId" : "something",
            "Subnet" : "something"
        },
        "us-west-2" :
        {
            "ImageId" : "something",
            "Subnet" : "something"
        }
    },
    "qa" : 
    {
        "us-east-1" :
        {
            "ImageId" : "something",
            "Subnet" : "something"
        },
        "us-west-2" :
        {
            "ImageId" : "something",
            "Subnet" : "something"
        }
    }
}

这里重要的一点是对象在"映射"和键之间交替".所以在这种情况下,"dev"是一个映射,"us-east-1"是一个键,"ImageId"是一个映射,和"某事"是一个关键.映射名称不能包含非字母数字字符,因此区域名称不能是映射.因此,使用环境作为第一个参数并使用区域名称作为第二个参数是必需的.

在我看来,像CloudFormation的Mappings部分有很多非常奇怪的任意规则,令我惊讶的是它不是更灵活,但你有它.

Answer 2

像这样的东西：

"ImageMap" : {
    "us-east-1" : { "dev" : "ami-11111111", "qa" : "ami-22222222" },
    "us-west-1" : { "dev" : "ami-33333333", "qa" : "ami-44444444" }
 }

然后访问这些值：

"Value" : {
    "Fn::FindInMap" : [
        "ImageMap", { "Ref" : "AWS::Region" }, { "Ref" : "EnvironmentType" }
    ]
}