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AWS CloudFormation
User Guide (API Version 2010-05-15)

Pseudo Parameters Reference

Pseudo Parameters are parameters that are predefined by AWS CloudFormation. You do not declare them in your template. Use them the same way as you would a parameter, as the argument for the Ref function.

Example

The following snippet assigns the value of the AWS::Region pseudo parameter to an output value:

JSON


"Outputs" : {
   "MyStacksRegion" : { "Value" : { "Ref" : "AWS::Region" } }
}

YAML

Outputs:
  MyStacksRegion:
    Value: !Ref "AWS::Region"

AWS::AccountId

Returns the AWS account ID of the account in which the stack is being created, such as 123456789012.

AWS::NotificationARNs

Returns the list of notification Amazon Resource Names (ARNs) for the current stack.

To get a single ARN from the list, use Fn::Select.

JSON


"myASGrpOne" : {
   "Type" : "AWS::AutoScaling::AutoScalingGroup",
   "Version" : "2009-05-15",
   "Properties" : {
      "AvailabilityZones" : [ "us-east-1a" ],
      "LaunchConfigurationName" : { "Ref" : "MyLaunchConfiguration" },
      "MinSize" : "0",
      "MaxSize" : "0",
      "NotificationConfigurations" : [{
         "TopicARN" : { "Fn::Select" : [ "0", { "Ref" : "AWS::NotificationARNs" } ] },
         "NotificationTypes" : [ "autoscaling:EC2_INSTANCE_LAUNCH", "autoscaling:EC2_INSTANCE_LAUNCH_ERROR" ]
      }]
   }
}

YAML

myASGrpOne:
  Type: AWS::AutoScaling::AutoScalingGroup
  Version: '2009-05-15'
  Properties:
    AvailabilityZones:
    - "us-east-1a"
    LaunchConfigurationName:
      Ref: MyLaunchConfiguration
    MinSize: '0'
    MaxSize: '0'
    NotificationConfigurations:
    - TopicARN:
        Fn::Select:
        - '0'
        - Ref: AWS::NotificationARNs
      NotificationTypes:
      - autoscaling:EC2_INSTANCE_LAUNCH
      - autoscaling:EC2_INSTANCE_LAUNCH_ERROR

AWS::NoValue

Removes the corresponding resource property when specified as a return value in the Fn::If intrinsic function.

For example, you can use the AWS::NoValue parameter when you want to use a snapshot for an Amazon RDS DB instance only if a snapshot ID is provided. If the UseDBSnapshot condition evaluates to true, AWS CloudFormation uses the DBSnapshotName parameter value for the DBSnapshotIdentifier property. If the condition evaluates to false, AWS CloudFormation removes the DBSnapshotIdentifier property.

JSON

"MyDB" : {
  "Type" : "AWS::RDS::DBInstance",
  "Properties" : {
    "AllocatedStorage" : "5",
    "DBInstanceClass" : "db.m1.small",
    "Engine" : "MySQL",
    "EngineVersion" : "5.5",
    "MasterUsername" : { "Ref" : "DBUser" },
    "MasterUserPassword" : { "Ref" : "DBPassword" },
    "DBParameterGroupName" : { "Ref" : "MyRDSParamGroup" },
    "DBSnapshotIdentifier" : {
      "Fn::If" : [
        "UseDBSnapshot",
        {"Ref" : "DBSnapshotName"},
        {"Ref" : "AWS::NoValue"}
      ]
    }
  }
}

YAML

MyDB:
  Type: AWS::RDS::DBInstance
  Properties:
    AllocatedStorage: '5'
    DBInstanceClass: db.m1.small
    Engine: MySQL
    EngineVersion: '5.5'
    MasterUsername:
      Ref: DBUser
    MasterUserPassword:
      Ref: DBPassword
    DBParameterGroupName:
      Ref: MyRDSParamGroup
    DBSnapshotIdentifier:
      Fn::If:
      - UseDBSnapshot
      - Ref: DBSnapshotName
      - Ref: AWS::NoValue

AWS::Region

Returns a string representing the AWS Region in which the encompassing resource is being created, such as us-west-2.

AWS::StackId

Returns the ID of the stack as specified with the aws cloudformation create-stack command, such as arn:aws:cloudformation:us-west-2:123456789012:stack/teststack/51af3dc0-da77-11e4-872e-1234567db123.

AWS::StackName

Returns the name of the stack as specified with the aws cloudformation create-stack command, such as teststack.