Custom resource request objects - AWS CloudFormation
Template developer request propertiesCustom resource provider request fields

Custom resource request objects

This topic describes the properties of the request object for a CloudFormation custom resource.

For an introduction to custom resources and how they work, see Create custom provisioning logic with custom resources.

Template developer request properties

The template developer uses the CloudFormation resource, AWS::CloudFormation::CustomResource, to specify a custom resource in a template.

In AWS::CloudFormation::CustomResource, all properties are defined by the custom resource provider. There is only one required property: ServiceToken.

ServiceTimeout

The maximum time, in seconds, that can elapse before a custom resource operation times out.

The value must be an integer from 1 to 3600. The default value is 3600 seconds (1 hour).

Required: No

Type: String

ServiceToken

The service token, such as an Amazon SNS topic ARN or Lambda function ARN. The service token must be from the same Region as the stack.

Required: Yes

Type: String

All other fields in the resource properties are optional and are sent, verbatim, to the custom resource provider in the request's ResourceProperties field. The provider defines both the names and the valid contents of these fields.

Custom resource provider request fields

These fields are sent in JSON requests from CloudFormation to the custom resource provider in the SNS topic that the provider has configured for this purpose.

RequestType

The request type is set by the CloudFormation stack operation (create-stack, update-stack, or delete-stack) that was initiated by the template developer for the stack that contains the custom resource.

Must be one of: Create, Update, or Delete. For more information, see Custom resource request types.

Required: Yes

Type: String

ResponseURL

The response URL identifies a presigned S3 bucket that receives responses from the custom resource provider to AWS CloudFormation.

Required: Yes

Type: String

StackId

The Amazon Resource Name (ARN) that identifies the stack that contains the custom resource.

Combining the StackId with the RequestId forms a value that you can use to uniquely identify a request on a particular custom resource.

Required: Yes

Type: String

RequestId

A unique ID for the request.

Combining the StackId with the RequestId forms a value that you can use to uniquely identify a request on a particular custom resource.

Required: Yes

Type: String

ResourceType

The template developer-chosen resource type of the custom resource in the CloudFormation template. Custom resource type names can be up to 60 characters long and can include alphanumeric and the following characters: _@-.

Required: Yes

Type: String

LogicalResourceId

The template developer-chosen name (logical ID) of the custom resource in the AWS CloudFormation template. This is provided to facilitate communication between the custom resource provider and the template developer.

Required: Yes

Type: String

PhysicalResourceId

A required custom resource provider-defined physical ID that is unique for that provider.

The value returned for a PhysicalResourceId can change custom resource update operations. If the value returned is the same, it is considered a normal update. If the value returned is different, AWS CloudFormation recognizes the update as a replacement and sends a delete request to the old resource. For more information, see AWS::CloudFormation::CustomResource.

Required: Always sent with Update and Delete requests; never sent with Create.

Type: String

ResourceProperties

This field contains the contents of the Properties object sent by the template developer. Its contents are defined by the custom resource provider.

Required: No

Type: JSON object

OldResourceProperties

Used only for Update requests. Contains the resource properties that were declared previous to the update request.

Required: Yes

Type: JSON object