feat(aws-events): Adds EventBus resources (#4609)

Adds the L2 resource for `CfnEventBus`

packages/@aws-cdk/aws-events/README.md

@@ -36,6 +36,9 @@ event when the pipeline changes it's state.
   enables different parts of an organization to look for and process the events
   that are of interest to them. A rule can customize the JSON sent to the
   target, by passing only certain parts or by overwriting it with a constant.
+* __EventBuses__: An event bus can receive events from your own custom applications
+  or it can receive events from applications and services created by AWS SaaS partners.
+  See [Creating an Event Bus](https://docs.aws.amazon.com/eventbridge/latest/userguide/create-event-bus.html).
 
 The `Rule` construct defines a CloudWatch events rule which monitors an
 event based on an [event

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

@@ -0,0 +1,225 @@
+import { Construct, IResource, Lazy, Resource, Stack } from '@aws-cdk/core';
+import { CfnEventBus } from './events.generated';
+
+/**
+ * Interface which all EventBus based classes MUST implement
+ */
+export interface IEventBus extends IResource {
+  /**
+   * The physical ID of this event bus resource
+   *
+   * @attribute
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-events-eventbus.html#cfn-events-eventbus-name
+   */
+  readonly eventBusName: string;
+
+  /**
+   * The ARN of this event bus resource
+   *
+   * @attribute
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-events-eventbus.html#Arn-fn::getatt
+   */
+  readonly eventBusArn: string;
+
+  /**
+   * The JSON policy of this event bus resource
+   *
+   * @attribute
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-events-eventbus.html#Policy-fn::getatt
+   */
+  readonly eventBusPolicy: string;
+
+  /**
+   * The partner event source to associate with this event bus resource
+   *
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-events-eventbus.html#cfn-events-eventbus-eventsourcename
+   */
+  readonly eventSourceName?: string;
+}
+
+/**
+ * Properties to define an event bus
+ */
+export interface EventBusProps {
+  /**
+   * The name of the event bus you are creating
+   * Note: If 'eventSourceName' is passed in, you cannot set this
+   *
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-events-eventbus.html#cfn-events-eventbus-name
+   * @default - automatically generated name
+   */
+  readonly eventBusName?: string;
+
+  /**
+   * The partner event source to associate with this event bus resource
+   * Note: If 'eventBusName' is passed in, you cannot set this
+   *
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-events-eventbus.html#cfn-events-eventbus-eventsourcename
+   * @default - no partner event source
+   */
+  readonly eventSourceName?: string;
+}
+
+/**
+ * Interface with properties necessary to import a reusable EventBus
+ */
+export interface EventBusAttributes {
+  /**
+   * The physical ID of this event bus resource
+   *
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-events-eventbus.html#cfn-events-eventbus-name
+   */
+  readonly eventBusName: string;
+
+  /**
+   * The ARN of this event bus resource
+   *
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-events-eventbus.html#Arn-fn::getatt
+   */
+  readonly eventBusArn: string;
+
+  /**
+   * The JSON policy of this event bus resource
+   *
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-events-eventbus.html#Policy-fn::getatt
+   */
+  readonly eventBusPolicy: string;
+
+  /**
+   * The partner event source to associate with this event bus resource
+   *
+   * @link https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-events-eventbus.html#cfn-events-eventbus-eventsourcename
+   * @default - no partner event source
+   */
+  readonly eventSourceName?: string;
+}
+
+/**
+ * Define a CloudWatch EventBus
+ *
+ * @resource AWS::Events::EventBus
+ */
+export class EventBus extends Resource implements IEventBus {
+
+  /**
+   * Import an existing event bus resource
+   * @param scope Parent construct
+   * @param id Construct ID
+   * @param eventBusArn ARN of imported event bus
+   */
+  public static fromEventBusArn(scope: Construct, id: string, eventBusArn: string): IEventBus {
+    const parts = Stack.of(scope).parseArn(eventBusArn);
+
+    class Import extends Resource implements IEventBus {
+      public readonly eventBusArn = eventBusArn;
+      public readonly eventBusName = parts.resourceName || '';
+      public readonly eventBusPolicy = '';
+    }
+
+    return new Import(scope, id);
+  }
+
+  /**
+   * Import an existing event bus resource
+   * @param scope Parent construct
+   * @param id Construct ID
+   * @param attrs Imported event bus properties
+   */
+  public static fromEventBusAttributes(scope: Construct, id: string, attrs: EventBusAttributes): IEventBus {
+    class Import extends Resource implements IEventBus {
+      public readonly eventBusArn = attrs.eventBusArn;
+      public readonly eventBusName = attrs.eventBusName;
+      public readonly eventBusPolicy = attrs.eventBusPolicy;
+      public readonly eventSourceName = attrs.eventSourceName;
+    }
+
+    return new Import(scope, id);
+  }
+
+  private static eventBusProps(defaultEventBusName: string, props?: EventBusProps) {
+    if (props) {
+      const { eventBusName, eventSourceName } = props;
+      const eventBusNameRegex = /^[\/\.\-_A-Za-z0-9]{1,256}$/;
+
+      if (eventBusName !== undefined && eventSourceName !== undefined) {
+        throw new Error(
+          `'eventBusName' and 'eventSourceName' cannot both be provided`
+        );
+      } else if (eventBusName !== undefined) {
+        if (eventBusName === 'default') {
+          throw new Error(
+            `'eventBusName' must not be 'default'`
+          );
+        } else if (eventBusName.indexOf('/') > -1) {
+          throw new Error(
+            `'eventBusName' must not contain '/'`
+          );
+        } else if (!eventBusNameRegex.test(eventBusName)) {
+          throw new Error(
+            `'eventBusName' must satisfy: ${eventBusNameRegex}`
+          );
+        }
+        return { eventBusName };
+      } else if (eventSourceName !== undefined) {
+        // Ex: aws.partner/PartnerName/acct1/repo1
+        const eventSourceNameRegex = /^aws\.partner(\/[\.\-_A-Za-z0-9]+){2,}$/;
+        if (!eventSourceNameRegex.test(eventSourceName)) {
+          throw new Error(
+            `'eventSourceName' must satisfy: ${eventSourceNameRegex}`
+          );
+        } else if (!eventBusNameRegex.test(eventSourceName)) {
+          throw new Error(
+            `'eventSourceName' must satisfy: ${eventBusNameRegex}`
+          );
+        }
+        return { eventBusName: eventSourceName, eventSourceName };
+      }
+    }
+    return { eventBusName: defaultEventBusName };
+  }
+
+  /**
+   * The physical ID of this event bus resource
+   */
+  public readonly eventBusName: string;
+
+  /**
+   * The ARN of the event bus, such as:
+   * arn:aws:events:us-east-2:123456789012:event-bus/aws.partner/PartnerName/acct1/repo1.
+   */
+  public readonly eventBusArn: string;
+
+  /**
+   * The policy for the event bus in JSON form.
+   */
+  public readonly eventBusPolicy: string;
+
+  /**
+   * The name of the partner event source
+   */
+  public readonly eventSourceName?: string;
+
+  constructor(scope: Construct, id: string, props?: EventBusProps) {
+    const { eventBusName, eventSourceName } = EventBus.eventBusProps(
+      Lazy.stringValue({ produce: () => this.node.uniqueId }),
+      props
+    );
+
+    super(scope, id, { physicalName: eventBusName });
+
+    const eventBus = new CfnEventBus(this, 'Resource', {
+      name: eventBusName,
+      eventSourceName
+    });
+
+    this.eventBusArn = this.getResourceArnAttribute(eventBus.attrArn, {
+      service: 'events',
+      resource: 'event-bus',
+      resourceName: eventBus.name
+    });
+
+    this.eventBusName = this.getResourceNameAttribute(eventBus.ref);
+    this.eventBusPolicy = eventBus.attrPolicy;
+    this.eventSourceName = eventBus.eventSourceName;
+  }
+}

packages/@aws-cdk/aws-events/lib/index.ts

@@ -2,6 +2,7 @@ export * from './input';
 export * from './rule';
 export * from './rule-ref';
 export * from './target';
+export * from './event-bus';
 export * from './event-pattern';
 export * from './schedule';
 export * from './on-event-options';