amazon-web-services - AWS cloudformation - 如何使用字符串参数来防止重复使用同一字符串

Question

1.
在我的代码中，字符串“HelloWorldApi”使用很多作为引用。
是否可以使用我定义的参数“APIName”来替换重复字符串“HelloWorldApi”，
这样当我创建另一个堆栈并重命名 API 时，就不需要将这些字符串一一更新？

{
    "AWSTemplateFormatVersion": "2010-09-09",
    
    "Parameters": {
      "APIName": {
        "Type": "String",
        "Default": "HelloWorldApi"
      }
    },
    "Resources": {
      "HelloWorldApi": {
        "Type": "AWS::ApiGateway::RestApi",
        "Properties": {
          "Name": "hello-api",
          "Description": "API used for practice",
          "FailOnWarnings": true
        }
      },
      "APIAuthorizer" :{
        "Type" : "AWS::ApiGateway::Authorizer",
        "Properties" : {
            "RestApiId" : {
              "Ref": "HelloWorldApi"
            }
          }
      },
      "BannerDBModel": {
          "Type" : "AWS::ApiGateway::Model",
          "Properties" : {
              "Name" : "postBannerModel",
              "RestApiId" : {
                "Ref": "HelloWorldApi"
              },
              "Schema" : {
                "$schema": "http://json-schema.org/draft-04/schema#",
                "title": "ProductsInputModel",
                "type": "object",
                "properties": {
                    "url": {"type": "string"}
                }                
              }
           }
      },
      "PostRequestValidator": {
        "Type" : "AWS::ApiGateway::RequestValidator",
        "Properties" : {
            "Name" : "PostRequestValidator",
            "RestApiId" : {
                "Ref": "HelloWorldApi"
            }
        }
      },
      "BannerResource": {
        "Type": "AWS::ApiGateway::Resource",
        "Properties": {
            "RestApiId": {
                "Ref": "HelloWorldApi"
            },
            "ParentId": {
                "Fn::GetAtt": [
                    "HelloWorldApi",
                    "RootResourceId"
                ]
            },
            "PathPart": "banner"
        }
      },
      "getBannerMethod": {
        "Type": "AWS::ApiGateway::Method",
        "DependsOn": ["HelloWorldApi"],
        "Properties": {
          "RestApiId": {
            "Ref": "HelloWorldApi"
          },
          "ResourceId": {
            "Ref": "BannerResource"
          },
          "HttpMethod": "GET",
          "AuthorizationType": "NONE"
        }
      },
      "Deployment": {
          "DependsOn": ["HelloWorldApi"],
          "Type": "AWS::ApiGateway::Deployment",
          "Properties": {
            "RestApiId": {
              "Ref": "HelloWorldApi"
            }
          }
      }
    }
  }

2.
假设我已经通过下面的代码创建了一个堆栈，如果 APIName 的默认值不小心设置为与原始版本不同的 HelloWorld，那么在我运行 updateStack 后会立即显示错误吗？
那会发生什么？正在创建另一个 API HelloWorld？

根据评论更新代码

{
    "AWSTemplateFormatVersion": "2010-09-09",
    
    "Parameters": {
      "RestAPI": {
        "Type": "String",
        "Default": "HelloWorldApi"
      }
    },
    "Resources": {
      "RestAPI": {
        "Type": "AWS::ApiGateway::RestApi",
        "Properties": {
          "Name": "hello-api",
          "Description": "API used for practice",
          "FailOnWarnings": true
        }
      },
      "APIAuthorizer" :{
        "Type" : "AWS::ApiGateway::Authorizer",
        "Properties" : {
            "RestApiId" : {
              "Ref": "RestAPI"
            }
          }
      },
      "BannerDBModel": {
          "Type" : "AWS::ApiGateway::Model",
          "Properties" : {
              "Name" : "postBannerModel",
              "RestApiId" : {
                "Ref": "RestAPI"
              },
              "Schema" : {
                "$schema": "http://json-schema.org/draft-04/schema#",
                "title": "ProductsInputModel",
                "type": "object",
                "properties": {
                    "url": {"type": "string"}
                }                
              }
           }
      }
    }
  }

Answer 1

要重用此模板，您应该将名为 HelloWorldApi 的资源重命名为更通用的名称。

如果您当前重命名了资源并尝试重新部署，则会在再次重新部署 API 时删除与 HelloWorldApi API 以及 API 本身关联的所有资源。

您使用的字符串引用的是 AWS::ApiGateway::RestApi 资源，而不是 APIName 参数中的值。如果您此时更新此参数值，它不会影响堆栈，因为它看起来好像没有被使用。

总之，Resources 中对字符串 HelloWorldApi 的引用是指 AWS::ApiGateway::RestApi 资源逻辑名称。

确保资源不与参数共享相同的名称。

模板如下所示

{
    "AWSTemplateFormatVersion": "2010-09-09",
    
    "Parameters": {
      "RestAPIName": {
        "Type": "String",
        "Default": "HelloWorldApi"
      }
    },
    "Resources": {
      "RestAPI": {
        "Type": "AWS::ApiGateway::RestApi",
        "Properties": {
          "Name": { "Ref": "RestAPIName" },
          "Description": "API used for practice",
          "FailOnWarnings": true
        }
      },
      "APIAuthorizer" :{
        "Type" : "AWS::ApiGateway::Authorizer",
        "Properties" : {
            "RestApiId" : {
              "Ref": "RestAPI"
            }
          }
      },
      "BannerDBModel": {
          "Type" : "AWS::ApiGateway::Model",
          "Properties" : {
              "Name" : "postBannerModel",
              "RestApiId" : {
                "Ref": "RestAPI"
              },
              "Schema" : {
                "$schema": "http://json-schema.org/draft-04/schema#",
                "title": "ProductsInputModel",
                "type": "object",
                "properties": {
                    "url": {"type": "string"}
                }                
              }
           }
      }
    }
  }