feat(aws-events): configure schema discovery on event bus

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

@@ -1,11 +1,33 @@
 import { Construct } from 'constructs';
 import { Archive, BaseArchiveProps } from './archive';
 import { CfnEventBus, CfnEventBusPolicy } from './events.generated';
+import * as eventschemas from '../../aws-eventschemas';
 import * as iam from '../../aws-iam';
 import * as kms from '../../aws-kms';
 import * as sqs from '../../aws-sqs';
 import { ArnFormat, IResource, Lazy, Names, Resource, Stack, Token } from '../../core';
 
+/**
+ * Properties to configure schema discovery on an event bus
+ */
+export interface SchemaDiscoveryProps {
+  /**
+   * Allows for the discovery of the event schemas that are sent to the event bus from another account
+   *
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-eventschemas-discoverer.html#cfn-eventschemas-discoverer-crossaccount
+   * @default - none
+   */
+  readonly crossAccount: boolean;
+
+  /**
+   * A description for the discoverer
+   *
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-eventschemas-discoverer.html#cfn-eventschemas-discoverer-description
+   * @default - none
+   */
+  readonly description: string;
+};
+
 /**
  * Interface which all EventBus based classes MUST implement
  */
@@ -50,6 +72,13 @@ export interface IEventBus extends IResource {
    */
   archive(id: string, props: BaseArchiveProps): Archive;
 
+  /**
+   * Create an EventBridge schema discoverer to automatically generate schemas based on events on this event bus.
+   *
+   * @param props Properties of the schema discoverer
+   */
+  schemaDiscovery(id: string, props?: SchemaDiscoveryProps): eventschemas.CfnDiscoverer;
+
   /**
    * Grants an IAM Principal to send custom events to the eventBus
    * so that they can be matched to rules.
@@ -175,6 +204,14 @@ abstract class EventBusBase extends Resource implements IEventBus {
     });
   }
 
+  public schemaDiscovery(id: string, props?: SchemaDiscoveryProps): eventschemas.CfnDiscoverer {
+    return new eventschemas.CfnDiscoverer(this, id, {
+      crossAccount: props?.crossAccount ?? true,
+      description: props?.description || `Schema Discoverer for ${this.eventBusName} Event Bus`,
+      sourceArn: this.eventBusArn,
+    });
+  }
+
   public grantPutEventsTo(grantee: iam.IGrantable): iam.Grant {
     return iam.Grant.addToPrincipal({
       grantee,

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

@@ -531,6 +531,132 @@ describe('event bus', () => {
     });
   });
 
+  test('can be configured for schema discovery with default properties', () => {
+    // GIVEN
+    const stack = new Stack();
+
+    // WHEN
+    const event = new EventBus(stack, 'Bus');
+
+    event.schemaDiscovery('MySchemaDiscoverer');
+
+    // THEN
+    Template.fromStack(stack).hasResourceProperties('AWS::Events::EventBus', {
+      Name: 'Bus',
+    });
+
+    Template.fromStack(stack).hasResourceProperties('AWS::EventSchemas::Discoverer', {
+      SourceArn: {
+        'Fn::GetAtt': [
+          'BusEA82B648',
+          'Arn',
+        ],
+      },
+      Description: {
+        'Fn::Join': [
+          '',
+          [
+            'Schema Discoverer for ',
+            {
+              Ref: 'BusEA82B648',
+            },
+            ' Event Bus',
+          ],
+        ],
+      },
+    });
+  });
+
+  test('can be configured for schema discovery with custom properties', () => {
+    // GIVEN
+    const stack = new Stack();
+
+    // WHEN
+    const event = new EventBus(stack, 'Bus');
+
+    event.schemaDiscovery('MySchemaDiscoverer', {
+      crossAccount: false,
+      description: 'A custom schema discovery description.',
+    });
+
+    // THEN
+    Template.fromStack(stack).hasResourceProperties('AWS::Events::EventBus', {
+      Name: 'Bus',
+    });
+
+    Template.fromStack(stack).hasResourceProperties('AWS::EventSchemas::Discoverer', {
+      SourceArn: {
+        'Fn::GetAtt': [
+          'BusEA82B648',
+          'Arn',
+        ],
+      },
+      Description: 'A custom schema discovery description.',
+      CrossAccount: false,
+    });
+  });
+
+  test('can be configured for schema discovery from an imported EventBus', () => {
+    // GIVEN
+    const stack = new Stack();
+
+    // WHEN
+    const bus = new EventBus(stack, 'Bus');
+
+    const importedBus = EventBus.fromEventBusArn(stack, 'ImportedBus', bus.eventBusArn);
+
+    importedBus.schemaDiscovery('MySchemaDiscoverer');
+
+    // THEN
+    Template.fromStack(stack).hasResourceProperties('AWS::Events::EventBus', {
+      Name: 'Bus',
+    });
+
+    Template.fromStack(stack).hasResourceProperties('AWS::EventSchemas::Discoverer', {
+      SourceArn: {
+        'Fn::GetAtt': [
+          'BusEA82B648',
+          'Arn',
+        ],
+      },
+      Description: {
+        'Fn::Join': [
+          '',
+          [
+            'Schema Discoverer for ',
+            {
+              'Fn::Select': [
+                1,
+                {
+                  'Fn::Split': [
+                    '/',
+                    {
+                      'Fn::Select': [
+                        5,
+                        {
+                          'Fn::Split': [
+                            ':',
+                            {
+                              'Fn::GetAtt': [
+                                'BusEA82B648',
+                                'Arn',
+                              ],
+                            },
+                          ],
+                        },
+                      ],
+                    },
+                  ],
+                },
+              ],
+            },
+            ' Event Bus',
+          ],
+        ],
+      },
+    });
+  });
+
   test('cross account event bus uses generated physical name', () => {
     // GIVEN
     const app = new App();