Table of contents

• Resources
  • Resource Parameters
    • Required Resource Properties
    • Logical Name
    • Optional Resource Properties
    • Resource Dependencies
    • Resource Properties
      • Condition
      • Metadata
      • Update Policy
      • Creation Policy
      • Deletion Policy
      • Other Properties
  • Custom Resources
• Full Resource List

Resources

The Resources section defines the AWS Resources that you wish to create using this template. All of the AWS Resources that are present in CloudFormation also appear in KloudFormation.

Info on Resources from AWS can be found here

Within the curly braces of the KloudFormation.create() function you have access to all of the resource types. To see a list in IntelliJ you can press the hotkey for code completion (Ctrl + Space on Mac).

Each resource has a function of the same name. That function has a receiver of type KloudFormation meaning that the function is available inside the { } braces

The following will create an S3 Bucket:

override fun KloudFormation.create() {
    bucket()
}

This produces the following template:

Resources:
  Bucket:
    Type: "AWS::S3::Bucket"

Resource Parameters

Each resource takes the following parameters:

• Required Resource Properties
• logicalName
• builder
• dependsOn
• resourceProperties

Required Resource Properties

class Stack: StackBuilder {
    override fun KloudFormation.create() {
        topic() // No required properties
        vPC(cidrBlock = +"0.0.0.0/0") // cidrBlock is required
    }
}

Logical Name

The Logical Name parameter determines what the resource will be named inside your stack. This will appear in the CloudFormation console.

Logical names are allocated for you if you do not set one and will appear as the capitalised name of the Resource followed by a number that increments.

Here is an example with three S3 Buckets:

bucket()
bucket()
bucket(logicalName = "MyBucket")

Produces

Bucket:
  Type: "AWS::S3::Bucket"
Bucket2:
  Type: "AWS::S3::Bucket"
MyBucket:
  Type: "AWS::S3::Bucket"

Optional Resource Properties

The builder is always the last parameter and is a function so can be passed as curly braces.

Any Properties that are optional appear as functions within the resource Builder which is passed to that function.

For example bucketName is optional so appears within the { } braces

bucket { 
    bucketName("MyBucket")
}

Resource Dependencies

You can pass a list of logical names to the dependsOn parameter so that CloudFormation creates the resources in the correct order.

val topic = topic()
val q = queue(dependsOn = listOf(topic.logicalName))

This Produces

Resources:
  Topic:
    Type: "AWS::SNS::Topic"
  Queue:
    Type: "AWS::SQS::Queue"
    DependsOn:
    - "Topic"

This can also be achieved by chaining with the then() function.

topic().then{ queue() }

Or, for multiple dependencies:

(topic() and topic()).then{ queue()  }

Resource Properties

Other metadata can be passed to the resourceProperties parameter.

ResourceProperties takes the following optional parameters:

• condition
• metadata
• updatePolicy
• creationPolicy
• deletionPolicy
• otherProperties

Condition

Condition has its own docs here

Metadata

The metadata section allows you to pass JSON. It takes the Value<JsonNode> type described here

For information on other Metadata elements like AWS::CloudFormation::Init, see Metadata

topic(resourceProperties = ResourceProperties(
    metadata = json(mapOf(
            "Key1" to "Value1",
            "Key2" to listOf("Value2", "Value3")
    ))
))

Update Policy

The update policy attribute tells CloudFormation what to do when this resource updates.

ResourceProperties(
    updatePolicy = UpdatePolicy(
            autoScalingReplacingUpdate = AutoScalingReplacingUpdate(willReplace = +true)
    )
)

Creation Policy

The creation policy attribute tells CloudFormation what to do when this resource is created.

ResourceProperties(
        creationPolicy = CreationPolicy(
                resourceSignal = CreationPolicy.ResourceSignal(
                        count = Value.Of(3),
                        timeout = +"PT15M"
                )
        )
)

Deletion Policy

The deletion policy attribute tells CloudFormation what to do when this resource is deleted.

ResourceProperties(
        deletionPolicy = DeletionPolicy.RETAIN.policy
)

Other Properties

If KloudFormation does not have the property you need to set, you can add any extra properties by passing them to the otherProperties attribute.

topic(resourceProperties = ResourceProperties(
        otherProperties = mapOf("MyProperty" to "Value")
))

Resources:
  Topic:
    Type: "AWS::SNS::Topic"
    Properties:
      MyProperty: "Value"

Custom Resources

There are two types of custom resources:

• AWS::CloudFormation::CustomResource
• Custom::<some string>

Both types can be made with the customResource() function provided. In order to change the type to Custom::<some string> invoke the asCustomResource function after building. Shown Below:

val standardCustomResource = customResource(
        logicalName = "DatabaseInitializer",
        serviceToken = +"arn:aws::xxxx:xxx"
).asCustomResource(properties = mapOf(
        "A" to "B",
        "C" to "D"
))
val customNameCustomResource = customResource(
        logicalName = "DatabaseInitializer2",
        serviceToken = +"arn:aws::xxxx:xxx"
).asCustomResource("Custom::DBInit")

Resources:
  DatabaseInitializer:
    Type: "AWS::CloudFormation::CustomResource"
    Properties:
      ServiceToken: "arn:aws::xxxx:xxx"
      A: "B"
      C: "D"
  DatabaseInitializer2:
    Type: "Custom::DBInit"
    Properties:
      ServiceToken: "arn:aws::xxxx:xxx"

Full Resource List

Note: All resources are generated and are up to date with Amazon’s specifications. If a resource is not listed below it is because this textual list is generated manually.