映射項目

選用的 Mappings 區段會比對索引鍵與對應的一組命名值。例如，如果您想要根據區域來設定值，則可以建立映射，而此映射使用區域名稱做為索引鍵，並包含您要為每個特定區域指定的值。您可以使用 Fn::FindInMap 內部函數來擷取映射中的值。

您不能在 Mappings 區段中包含參數、虛擬參數或內部函數。

語法

Mappings 區段由索引鍵名稱 Mappings 組成。映射中的索引鍵必須是常值字串。值可以是 String 或 List 類型。下列範例所顯示的 Mappings 區段包含名為 Mapping01 (邏輯名稱) 的單一映射。

在映射內，每個映射都是後面接著另一個映射的索引鍵。該金鑰必須是名稱值對的映射和映射中唯一的映射。

JSON

"Mappings" : {
  "Mapping01" : {
    "Key01" : {
      "Name" : "Value01"
    },
    "Key02" : {
      "Name" : "Value02"
    },
    "Key03" : {
      "Name" : "Value03"
    }
  }
}

YAML

Mappings: 
  Mapping01: 
    Key01: 
      Name: Value01
    Key02: 
      Name: Value02
    Key03: 
      Name: Value03

範例

基本映射

下列範例顯示具有映射 Mappings 的 RegionMap 區段，內含映射至包含單一字串值之名稱值對的五個索引鍵。索引鍵是區域名稱。每個名稱/值對都是以索引鍵代表之區域中 HVM64 AMI 的 AMI ID。

名稱/值對會有名稱 (在此範例中為 HVM64) 和值。藉由命名這些值，您可以將多組的值映射至一個索引鍵。

JSON

"Mappings" : {
  "RegionMap" : {
    "us-east-1"      : { "HVM64" : "ami-0ff8a91507f77f867"},
    "us-west-1"      : { "HVM64" : "ami-0bdb828fd58c52235"},
    "eu-west-1"      : { "HVM64" : "ami-047bb4163c506cd98"},
    "ap-southeast-1" : { "HVM64" : "ami-08569b978cc4dfa10"},
    "ap-northeast-1" : { "HVM64" : "ami-06cd52961ce9f0d85"}
  }
}

YAML

Mappings: 
  RegionMap: 
    us-east-1: 
      "HVM64": "ami-0ff8a91507f77f867"
    us-west-1: 
      "HVM64": "ami-0bdb828fd58c52235"
    eu-west-1: 
      "HVM64": "ami-047bb4163c506cd98"
    ap-southeast-1: 
      "HVM64": "ami-08569b978cc4dfa10"
    ap-northeast-1: 
      "HVM64": "ami-06cd52961ce9f0d85"

具有多個值的映射

下列範例的區域索引鍵映射至兩組值：一個名為 HVM64，另一個名為 HVMG2。

JSON

    "RegionMap" : {
      "us-east-1"        : {"HVM64" : "ami-0ff8a91507f77f867", "HVMG2" : "ami-0a584ac55a7631c0c"},
      "us-west-1"        : {"HVM64" : "ami-0bdb828fd58c52235", "HVMG2" : "ami-066ee5fd4a9ef77f1"},
      "eu-west-1"        : {"HVM64" : "ami-047bb4163c506cd98", "HVMG2" : "ami-0a7c483d527806435"},
      "ap-northeast-1"   : {"HVM64" : "ami-06cd52961ce9f0d85", "HVMG2" : "ami-053cdd503598e4a9d"},
      "ap-southeast-1"   : {"HVM64" : "ami-08569b978cc4dfa10", "HVMG2" : "ami-0be9df32ae9f92309"}
    }

YAML

RegionMap: 
    us-east-1:
      HVM64: ami-0ff8a91507f77f867
      HVMG2: ami-0a584ac55a7631c0c
    us-west-1:
      HVM64: ami-0bdb828fd58c52235
      HVMG2: ami-066ee5fd4a9ef77f1
    eu-west-1:
      HVM64: ami-047bb4163c506cd98
      HVMG2: ami-0a7c483d527806435
    ap-northeast-1:
      HVM64: ami-06cd52961ce9f0d85
      HVMG2: ami-053cdd503598e4a9d
    ap-southeast-1:
      HVM64: ami-08569b978cc4dfa10
      HVMG2: ami-0be9df32ae9f92309

從映射傳回值

您可以使用 Fn::FindInMap 函數，以根據指定的索引鍵來傳回命名值。下列範例範本包含 Amazon EC2 資源，而其 ImageId 屬性是由 FindInMap 函數指派。該FindInMap函數將 key 指定為創建堆棧的區域（使用AWS::Region 偽參數），並HVM64作為要映射到的值的名稱。

JSON

{
  "AWSTemplateFormatVersion" : "2010-09-09",

  "Mappings" : {
    "RegionMap" : {
      "us-east-1"        : {"HVM64" : "ami-0ff8a91507f77f867", "HVMG2" : "ami-0a584ac55a7631c0c"},
      "us-west-1"        : {"HVM64" : "ami-0bdb828fd58c52235", "HVMG2" : "ami-066ee5fd4a9ef77f1"},
      "eu-west-1"        : {"HVM64" : "ami-047bb4163c506cd98", "HVMG2" : "ami-0a7c483d527806435"},
      "ap-northeast-1"   : {"HVM64" : "ami-06cd52961ce9f0d85", "HVMG2" : "ami-053cdd503598e4a9d"},
      "ap-southeast-1"   : {"HVM64" : "ami-08569b978cc4dfa10", "HVMG2" : "ami-0be9df32ae9f92309"}
    }
  },

  "Resources" : {
    "myEC2Instance" : {
      "Type" : "AWS::EC2::Instance",
      "Properties" : {
        "ImageId" : { "Fn::FindInMap" : [ "RegionMap", { "Ref" : "AWS::Region" }, "HVM64"]},
        "InstanceType" : "m1.small"
      }
    }
  }
}

YAML

AWSTemplateFormatVersion: "2010-09-09"
Mappings: 
  RegionMap: 
    us-east-1:
      HVM64: ami-0ff8a91507f77f867
      HVMG2: ami-0a584ac55a7631c0c
    us-west-1:
      HVM64: ami-0bdb828fd58c52235
      HVMG2: ami-066ee5fd4a9ef77f1
    eu-west-1:
      HVM64: ami-047bb4163c506cd98
      HVMG2: ami-0a7c483d527806435
    ap-northeast-1:
      HVM64: ami-06cd52961ce9f0d85
      HVMG2: ami-053cdd503598e4a9d
    ap-southeast-1:
      HVM64: ami-08569b978cc4dfa10
      HVMG2: ami-0be9df32ae9f92309
Resources: 
  myEC2Instance: 
    Type: "AWS::EC2::Instance"
    Properties: 
      ImageId: !FindInMap [RegionMap, !Ref "AWS::Region", HVM64]
      InstanceType: m1.small

輸入參數和 Fn::FindInMap

您可以搭配使用輸入參數與 Fn::FindInMap 函數，以參照映射中的特定值。例如，假設您有一份映射至特定 AMI ID 的區域和環境類型清單。您可以使用輸入參數 (EnvironmentType) 來選取您堆疊所使用的 AMI ID。若要判斷區域，請使用AWS::Region偽參數，該參數會取得您在其中建立堆疊的 AWS Region。

JSON

{
  "Parameters" : {
    "EnvironmentType": {
      "Description": "The environment type",
      "Type": "String",
      "Default": "test",
      "AllowedValues": ["prod", "test"],
      "ConstraintDescription": "must be a prod or test"
    }
  },
	
  "Mappings" : {
    "RegionAndInstanceTypeToAMIID" : {
      "us-east-1": {
        "test": "ami-8ff710e2",
        "prod": "ami-f5f41398"
      },
      "us-west-2" : {
        "test" : "ami-eff1028f",
        "prod" : "ami-d0f506b0"
      },

      ...other regions and AMI IDs...

    }
  },

  "Resources" : {
  
   ...other resources...

    },
    
  "Outputs" : {
    "TestOutput" : {
      "Description" : "Return the name of the AMI ID that matches the region and environment type keys",
      "Value" : { "Fn::FindInMap" : [ "RegionAndInstanceTypeToAMIID", { "Ref" : "AWS::Region" }, { "Ref" : "EnvironmentType" } ]}
    }
  }
  
}

YAML

  Parameters: 
    EnvironmentType: 
      Description: The environment type
      Type: String
      Default: test
      AllowedValues: 
        - prod
        - test
      ConstraintDescription: must be a prod or test
  Mappings: 
    RegionAndInstanceTypeToAMIID: 
      us-east-1: 
        test: "ami-8ff710e2"
        prod: "ami-f5f41398"
      us-west-2: 
        test: "ami-eff1028f"
        prod: "ami-d0f506b0"
        
      ...other regions and AMI IDs...
  
  Resources:
  
   ...other resources...

  Outputs: 
    TestOutput: 
      Description: Return the name of the AMI ID that matches the region and environment type keys
      Value: !FindInMap [RegionAndInstanceTypeToAMIID, !Ref "AWS::Region", !Ref EnvironmentType]