fix(route53): vpc region in template overridden by stack region (#20530)

Fixes #20496 

This PR implements the proposed change in #20496 - When a region is set in the vpc it is used in the CloudFormation template. Otherwise the region from the respective stack is used.

----

### All Submissions:

* [x] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md)

### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [x] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/master/INTEGRATION_TESTS.md)?
	* [x] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-ec2/lib/vpc.ts

@@ -763,6 +763,13 @@ export interface VpcAttributes {
    * VPN gateway's identifier
    */
   readonly vpnGatewayId?: string;
+
+  /**
+   * The region the VPC is in
+   *
+   * @default - The region of the stack where the VPC belongs to
+   */
+  readonly region?: string;
 }
 
 export interface SubnetAttributes {
@@ -1203,7 +1210,7 @@ export class Vpc extends VpcBase {
       dummyValue: undefined,
     }).value;
 
-    return new LookedUpVpc(scope, id, attributes || DUMMY_VPC_PROPS, attributes === undefined);
+    return new LookedUpVpc(scope, id, attributes ?? DUMMY_VPC_PROPS, attributes === undefined);
 
     /**
      * Prefixes all keys in the argument with `tag:`.`
@@ -2008,7 +2015,9 @@ class ImportedVpc extends VpcBase {
   private readonly cidr?: string | undefined;
 
   constructor(scope: Construct, id: string, props: VpcAttributes, isIncomplete: boolean) {
-    super(scope, id);
+    super(scope, id, {
+      region: props.region,
+    });
 
     this.vpcId = props.vpcId;
     this.vpcArn = Arn.format({
@@ -2058,7 +2067,9 @@ class LookedUpVpc extends VpcBase {
   private readonly cidr?: string | undefined;
 
   constructor(scope: Construct, id: string, props: cxapi.VpcContextResponse, isIncomplete: boolean) {
-    super(scope, id);
+    super(scope, id, {
+      region: props.region,
+    });
 
     this.vpcId = props.vpcId;
     this.vpcArn = Arn.format({

packages/@aws-cdk/aws-ec2/test/integ.vpc-lookup.ts

@@ -0,0 +1,48 @@
+import * as cdk from '@aws-cdk/core';
+import { IntegTest } from '@aws-cdk/integ-tests';
+import * as ec2 from '../lib';
+
+const appWithVpc = new cdk.App();
+const stack = new cdk.Stack(appWithVpc, 'StackWithVpc', {
+  env: {
+    region: 'eu-west-1',
+    account: '123456',
+  },
+});
+
+const testVpc = new ec2.Vpc(stack, 'MyVpc', {
+  vpcName: 'my-vpc-name',
+});
+
+const appUnderTest = new cdk.App();
+const stackLookup = new cdk.Stack(appUnderTest, 'StackUnderTest', {
+  env: {
+    region: 'us-east-2',
+    account: '123456',
+  },
+});
+
+const vpcFromVpcAttributes = ec2.Vpc.fromVpcAttributes(stackLookup, 'VpcFromVpcAttributes', {
+  region: 'eu-west-1',
+  availabilityZones: ['eu-west-1a'],
+  vpcId: testVpc.vpcId,
+});
+
+const vpcFromLookup = ec2.Vpc.fromLookup(stack, 'VpcFromLookup', {
+  region: 'eu-west-1',
+  vpcName: 'my-vpc-name',
+});
+
+new cdk.CfnOutput(stackLookup, 'OutputFromVpcAttributes', {
+  value: `Region fromVpcAttributes: ${vpcFromVpcAttributes.env.region}`,
+});
+
+new cdk.CfnOutput(stackLookup, 'OutputFromLookup', {
+  value: `Region fromLookup: ${vpcFromLookup.env.region}`,
+});
+
+new IntegTest(appUnderTest, 'ArchiveTest', {
+  testCases: [stackLookup],
+});
+appWithVpc.synth();
+appUnderTest.synth();

packages/@aws-cdk/aws-ec2/test/vpc-lookup.integ.snapshot/ArchiveTestDefaultTestDeployAssert3405726A.assets.json

@@ -0,0 +1,19 @@
+{
+  "version": "21.0.0",
+  "files": {
+    "21fbb51d7b23f6a6c262b46a9caee79d744a3ac019fd45422d988b96d44b2a22": {
+      "source": {
+        "path": "ArchiveTestDefaultTestDeployAssert3405726A.template.json",
+        "packaging": "file"
+      },
+      "destinations": {
+        "current_account-current_region": {
+          "bucketName": "cdk-hnb659fds-assets-${AWS::AccountId}-${AWS::Region}",
+          "objectKey": "21fbb51d7b23f6a6c262b46a9caee79d744a3ac019fd45422d988b96d44b2a22.json",
+          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-file-publishing-role-${AWS::AccountId}-${AWS::Region}"
+        }
+      }
+    }
+  },
+  "dockerImages": {}
+}

packages/@aws-cdk/aws-ec2/test/vpc-lookup.integ.snapshot/ArchiveTestDefaultTestDeployAssert3405726A.template.json

@@ -0,0 +1,36 @@
+{
+ "Parameters": {
+  "BootstrapVersion": {
+   "Type": "AWS::SSM::Parameter::Value<String>",
+   "Default": "/cdk-bootstrap/hnb659fds/version",
+   "Description": "Version of the CDK Bootstrap resources in this environment, automatically retrieved from SSM Parameter Store. [cdk:skip]"
+  }
+ },
+ "Rules": {
+  "CheckBootstrapVersion": {
+   "Assertions": [
+    {
+     "Assert": {
+      "Fn::Not": [
+       {
+        "Fn::Contains": [
+         [
+          "1",
+          "2",
+          "3",
+          "4",
+          "5"
+         ],
+         {
+          "Ref": "BootstrapVersion"
+         }
+        ]
+       }
+      ]
+     },
+     "AssertDescription": "CDK bootstrap stack version 6 required. Please run 'cdk bootstrap' with a recent version of the CDK CLI."
+    }
+   ]
+  }
+ }
+}

packages/@aws-cdk/aws-ec2/test/vpc-lookup.integ.snapshot/StackUnderTest.assets.json

@@ -0,0 +1,20 @@
+{
+  "version": "21.0.0",
+  "files": {
+    "cfac1423efb7c99cadc3f40367c753fe5b1527d9a6950c096ba326fabac4c89f": {
+      "source": {
+        "path": "StackUnderTest.template.json",
+        "packaging": "file"
+      },
+      "destinations": {
+        "123456-us-east-2": {
+          "bucketName": "cdk-hnb659fds-assets-123456-us-east-2",
+          "objectKey": "cfac1423efb7c99cadc3f40367c753fe5b1527d9a6950c096ba326fabac4c89f.json",
+          "region": "us-east-2",
+          "assumeRoleArn": "arn:${AWS::Partition}:iam::123456:role/cdk-hnb659fds-file-publishing-role-123456-us-east-2"
+        }
+      }
+    }
+  },
+  "dockerImages": {}
+}

packages/@aws-cdk/aws-ec2/test/vpc-lookup.integ.snapshot/StackUnderTest.template.json

@@ -0,0 +1,44 @@
+{
+ "Outputs": {
+  "OutputFromVpcAttributes": {
+   "Value": "Region fromVpcAttributes: eu-west-1"
+  },
+  "OutputFromLookup": {
+   "Value": "Region fromLookup: eu-west-1"
+  }
+ },
+ "Parameters": {
+  "BootstrapVersion": {
+   "Type": "AWS::SSM::Parameter::Value<String>",
+   "Default": "/cdk-bootstrap/hnb659fds/version",
+   "Description": "Version of the CDK Bootstrap resources in this environment, automatically retrieved from SSM Parameter Store. [cdk:skip]"
+  }
+ },
+ "Rules": {
+  "CheckBootstrapVersion": {
+   "Assertions": [
+    {
+     "Assert": {
+      "Fn::Not": [
+       {
+        "Fn::Contains": [
+         [
+          "1",
+          "2",
+          "3",
+          "4",
+          "5"
+         ],
+         {
+          "Ref": "BootstrapVersion"
+         }
+        ]
+       }
+      ]
+     },
+     "AssertDescription": "CDK bootstrap stack version 6 required. Please run 'cdk bootstrap' with a recent version of the CDK CLI."
+    }
+   ]
+  }
+ }
+}

packages/@aws-cdk/aws-ec2/test/vpc-lookup.integ.snapshot/StackWithVpc.assets.json

@@ -0,0 +1,20 @@
+{
+  "version": "21.0.0",
+  "files": {
+    "628a32283150d3af24efb3a11967996306884a3835ac731ab35822da2ce7e9ff": {
+      "source": {
+        "path": "StackWithVpc.template.json",
+        "packaging": "file"
+      },
+      "destinations": {
+        "123456-eu-west-1": {
+          "bucketName": "cdk-hnb659fds-assets-123456-eu-west-1",
+          "objectKey": "628a32283150d3af24efb3a11967996306884a3835ac731ab35822da2ce7e9ff.json",
+          "region": "eu-west-1",
+          "assumeRoleArn": "arn:${AWS::Partition}:iam::123456:role/cdk-hnb659fds-file-publishing-role-123456-eu-west-1"
+        }
+      }
+    }
+  },
+  "dockerImages": {}
+}