add PhysicalResourceId to CloudFormation Custom Resource interface, where appropriate

PhysicalResourceId is "always sent with Update and Delete requests;
never sent with Create" (according to AWS docs) and is commonly
required to actually perform the work needed to do an update or
delete of the resource. This PR encodes that contract and makes life a
bit easier for developers implementing update/delete, since they won't
have to deal with the optionality of the value in the event encoding.

Author: bpholt

lambda-cloudformation-custom-resource/src/main/scala/feral/lambda/cloudformation/CloudFormationCustomResource.scala

@@ -30,8 +30,12 @@ import org.http4s.client.dsl.Http4sClientDsl
 
 trait CloudFormationCustomResource[F[_], Input, Output] {
   def createResource(input: Input): F[HandlerResponse[Output]]
-  def updateResource(input: Input): F[HandlerResponse[Output]]
-  def deleteResource(input: Input): F[HandlerResponse[Output]]
+  def updateResource(
+      input: Input,
+      physicalResourceId: PhysicalResourceId): F[HandlerResponse[Output]]
+  def deleteResource(
+      input: Input,
+      physicalResourceId: PhysicalResourceId): F[HandlerResponse[Output]]
 }
 
 object CloudFormationCustomResource {
@@ -47,11 +51,11 @@ object CloudFormationCustomResource {
     import http4sClientDsl._
 
     env.event.flatMap { event =>
-      (event.RequestType match {
-        case CreateRequest => handler.createResource(event.ResourceProperties)
-        case UpdateRequest => handler.updateResource(event.ResourceProperties)
-        case DeleteRequest => handler.deleteResource(event.ResourceProperties)
-        case OtherRequestType(other) => illegalRequestType(other)
+      ((event.RequestType, event.PhysicalResourceId) match {
+        case (CreateRequest, None) => handler.createResource(event.ResourceProperties)
+        case (UpdateRequest, Some(id)) => handler.updateResource(event.ResourceProperties, id)
+        case (DeleteRequest, Some(id)) => handler.deleteResource(event.ResourceProperties, id)
+        case (other, _) => illegalRequestType(other.toString)
       }).attempt
         .map(_.fold(exceptionResponse(event)(_), successResponse(event)(_)))
         .flatMap { resp => client.successful(PUT(resp.asJson, event.ResponseURL)) }

lambda-cloudformation-custom-resource/src/main/scala/feral/lambda/cloudformation/package.scala

@@ -72,7 +72,9 @@ package cloudformation {
     case object CreateRequest extends CloudFormationRequestType
     case object UpdateRequest extends CloudFormationRequestType
     case object DeleteRequest extends CloudFormationRequestType
-    final case class OtherRequestType(requestType: String) extends CloudFormationRequestType
+    final case class OtherRequestType(requestType: String) extends CloudFormationRequestType {
+      override def toString: String = requestType
+    }
 
     implicit val encoder: Encoder[CloudFormationRequestType] = {
       case CreateRequest => "Create".asJson

lambda-cloudformation-custom-resource/src/test/scala/feral/lambda/cloudformation/CloudFormationCustomResourceArbitraries.scala

@@ -165,7 +165,7 @@ trait CloudFormationCustomResourceArbitraries {
       requestId <- arbitrary[RequestId]
       resourceType <- arbitrary[ResourceType]
       logicalResourceId <- arbitrary[LogicalResourceId]
-      physicalResourceId <- arbitrary[Option[PhysicalResourceId]]
+      physicalResourceId <- arbitrary[PhysicalResourceId]
       resourceProperties <- arbitrary[A]
       oldResourceProperties <- arbitrary[Option[JsonObject]]
     } yield CloudFormationCustomResourceRequest(
@@ -175,7 +175,7 @@ trait CloudFormationCustomResourceArbitraries {
       requestId,
       resourceType,
       logicalResourceId,
-      physicalResourceId,
+      if (requestType == CreateRequest) None else physicalResourceId.some,
       resourceProperties,
       oldResourceProperties
     )

lambda-cloudformation-custom-resource/src/test/scala/feral/lambda/cloudformation/ResponseSerializationSuite.scala

@@ -83,7 +83,7 @@ class ResponseSerializationSuite
                   }
                 )
                 .deepDropNullValues
-            case _ =>
+            case CreateRequest =>
               Json.obj(
                 "Status" -> "SUCCESS".asJson,
                 "PhysicalResourceId" -> convertInputToFakePhysicalResourceId(
@@ -93,6 +93,15 @@ class ResponseSerializationSuite
                 "LogicalResourceId" -> event.LogicalResourceId.asJson,
                 "Data" -> event.RequestType.asJson
               )
+            case UpdateRequest | DeleteRequest =>
+              Json.obj(
+                "Status" -> "SUCCESS".asJson,
+                "PhysicalResourceId" -> event.PhysicalResourceId.get.asJson,
+                "StackId" -> event.StackId.asJson,
+                "RequestId" -> event.RequestId.asJson,
+                "LogicalResourceId" -> event.LogicalResourceId.asJson,
+                "Data" -> event.RequestType.asJson
+              )
           }
 
           expect(body eqv expectedJson)
@@ -142,14 +151,16 @@ object ResponseSerializationSuite {
         convertInputToFakePhysicalResourceId(input),
         CreateRequest.some.widen[CloudFormationRequestType]).pure[F]
 
-    override def updateResource(input: String): F[HandlerResponse[CloudFormationRequestType]] =
-      HandlerResponse(
-        convertInputToFakePhysicalResourceId(input),
-        UpdateRequest.some.widen[CloudFormationRequestType]).pure[F]
+    override def updateResource(
+        input: String,
+        physicalResourceId: PhysicalResourceId): F[HandlerResponse[CloudFormationRequestType]] =
+      HandlerResponse(physicalResourceId, UpdateRequest.some.widen[CloudFormationRequestType])
+        .pure[F]
 
-    override def deleteResource(input: String): F[HandlerResponse[CloudFormationRequestType]] =
-      HandlerResponse(
-        convertInputToFakePhysicalResourceId(input),
-        DeleteRequest.some.widen[CloudFormationRequestType]).pure[F]
+    override def deleteResource(
+        input: String,
+        physicalResourceId: PhysicalResourceId): F[HandlerResponse[CloudFormationRequestType]] =
+      HandlerResponse(physicalResourceId, DeleteRequest.some.widen[CloudFormationRequestType])
+        .pure[F]
   }
 }