fix(events): imported EventBus does not correctly register source account (#13481)

Parses the event bus arn to give the account and region to the underlying Resource.

fixes #13469


----

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

Author: thantos

packages/@aws-cdk/aws-events/lib/event-bus.ts

@@ -282,7 +282,11 @@ class ImportedEventBus extends EventBusBase {
   public readonly eventBusPolicy: string;
   public readonly eventSourceName?: string;
   constructor(scope: Construct, id: string, attrs: EventBusAttributes) {
-    super(scope, id);
+    const arnParts = Stack.of(scope).parseArn(attrs.eventBusArn);
+    super(scope, id, {
+      account: arnParts.account,
+      region: arnParts.region,
+    });
 
     this.eventBusArn = attrs.eventBusArn;
     this.eventBusName = attrs.eventBusName;

packages/@aws-cdk/aws-events/test/test.event-bus.ts

@@ -1,6 +1,6 @@
 import { expect, haveResource } from '@aws-cdk/assert';
 import * as iam from '@aws-cdk/aws-iam';
-import { Aws, CfnResource, Stack } from '@aws-cdk/core';
+import { Aws, CfnResource, Stack, Arn } from '@aws-cdk/core';
 import { Test } from 'nodeunit';
 import { EventBus } from '../lib';
 
@@ -55,6 +55,65 @@ export = {
     test.done();
   },
 
+  'imported event bus'(test: Test) {
+    const stack = new Stack();
+
+    const eventBus = new EventBus(stack, 'Bus');
+
+    const importEB = EventBus.fromEventBusArn(stack, 'ImportBus', eventBus.eventBusArn);
+
+    // WHEN
+    new CfnResource(stack, 'Res', {
+      type: 'Test::Resource',
+      properties: {
+        EventBusArn1: eventBus.eventBusArn,
+        EventBusArn2: importEB.eventBusArn,
+      },
+    });
+
+    expect(stack).to(haveResource('Test::Resource', {
+      EventBusArn1: { 'Fn::GetAtt': ['BusEA82B648', 'Arn'] },
+      EventBusArn2: { 'Fn::GetAtt': ['BusEA82B648', 'Arn'] },
+    }));
+
+    test.done();
+  },
+
+  'same account imported event bus has right resource env'(test: Test) {
+    const stack = new Stack();
+
+    const eventBus = new EventBus(stack, 'Bus');
+
+    const importEB = EventBus.fromEventBusArn(stack, 'ImportBus', eventBus.eventBusArn);
+
+    // WHEN
+    test.deepEqual(stack.resolve(importEB.env.account), { 'Fn::Select': [4, { 'Fn::Split': [':', { 'Fn::GetAtt': ['BusEA82B648', 'Arn'] }] }] });
+    test.deepEqual(stack.resolve(importEB.env.region), { 'Fn::Select': [3, { 'Fn::Split': [':', { 'Fn::GetAtt': ['BusEA82B648', 'Arn'] }] }] });
+
+    test.done();
+  },
+
+  'cross account imported event bus has right resource env'(test: Test) {
+    const stack = new Stack();
+
+    const arnParts = {
+      resource: 'bus',
+      service: 'events',
+      account: 'myAccount',
+      region: 'us-west-1',
+    };
+
+    const arn = Arn.format(arnParts, stack);
+
+    const importEB = EventBus.fromEventBusArn(stack, 'ImportBus', arn);
+
+    // WHEN
+    test.deepEqual(importEB.env.account, arnParts.account);
+    test.deepEqual(importEB.env.region, arnParts.region);
+
+    test.done();
+  },
+
   'can get bus name'(test: Test) {
     // GIVEN
     const stack = new Stack();