fix(custom-resources): support region for AwsCustomResource

packages/@aws-cdk/custom-resources/lib/aws-custom-resource-provider/index.ts

@@ -62,11 +62,18 @@ export async function handler(event: AWSLambda.CloudFormationCustomResourceEvent
  const call: AwsSdkCall | undefined = event.ResourceProperties[event.RequestType];
 
  if (call) {
- const awsService = new (AWS as any)[call.service](call.apiVersion && { apiVersion: call.apiVersion });
+ const awsService = new (AWS as any)[call.service]({
+ apiVersion: call.apiVersion,
+ region: call.region,
+ });
 
  try {
  const response = await awsService[call.action](call.parameters && decodeBooleans(call.parameters)).promise();
- flatData = flatten(response);
+ flatData = {
+ apiVersion: awsService.config.apiVersion, // For test purposes: check if apiVersion was correctly passed.
+ region: awsService.config.region, // For test purposes: check if region was correctly passed.
+ ...flatten(response),
+ };
  data = call.outputPath
  ? filterKeys(flatData, k => k.startsWith(call.outputPath!))
  : flatData;

packages/@aws-cdk/custom-resources/lib/aws-custom-resource.ts

@@ -42,7 +42,7 @@ export interface AwsSdkCall {
  * resource id. Either `physicalResourceId` or `physicalResourceIdPath`
  * must be specified for onCreate or onUpdate calls.
  *
- * @default no path
+ * @default - no path
  */
  readonly physicalResourceIdPath?: string;
 
@@ -51,7 +51,7 @@ export interface AwsSdkCall {
  * `physicalResourceId` or `physicalResourceIdPath` must be specified for
  * onCreate or onUpdate calls.
  *
- * @default no physical resource id
+ * @default - no physical resource id
  */
  readonly physicalResourceId?: string;
 
@@ -60,18 +60,27 @@ export interface AwsSdkCall {
  * `Error` object will be tested against this pattern. If there is a match an
  * error will not be thrown.
  *
- * @default do not catch errors
+ * @default - do not catch errors
  */
  readonly catchErrorPattern?: string;
 
  /**
  * API version to use for the service
  *
  * @see https://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/locking-api-versions.html
- * @default use latest available API version
+ * @default - use latest available API version
  */
  readonly apiVersion?: string;
 
+ /**
+ * The region to send service requests to.
+ * **Note: Cross-region operations are generally considered an anti-pattern.**
+ * **Consider first deploying a stack in that region.**
+ *
+ * @default - the region where this custom resource is deployed
+ */
+ readonly region?: string;
+
  /**
  * Restrict the data returned by the custom resource to a specific path in
  * the API response. Use this to limit the data returned by the custom