feat(aws-eventbridge-sqs, aws-events-rule-sqs, aws-eventbridge-stepfunctions, aws-events-rule-step-function): custom EventBus support (#363)

* enhanced construct to support custom EventBus

* fix linting issues

* fix PR review comments

* refactoring and use IEventBus instead of EventBus

* enchanced aws-eventbridge-sqs construct to support custom eventbus

* enhanced aws-eventbridge-stepfunctions construct to support custom eventbus

* update the props naming convention to align with existing constructs

* updated the props documentation

* upated exisitingEventBusInterface & eventBusProps description

* upated naming convention as per other aws-evenbridge-* standards

* enhance aws-eventbridge-stepfunctions to support custom eventbus

* enhance aws-events-rule-step-function construct to support custom eventbus

* enhance aws-events-rule-sqs to support custom eventbus

* refactor

* fix viperlight issue

* refactoring to keep it consistent with other constructs

* update documentation

* fix merge issues

* remove duplicate props

Co-authored-by: santhosh <>

Author: surukonda

Diff for: .viperlightignore

@@ -30,8 +30,8 @@ source/patterns/@aws-solutions-constructs/aws-lambda-step-function/test/lambda-s
 source/patterns/@aws-solutions-constructs/aws-lambda-stepfunctions/test/lambda-stepfunctions.test.ts:130
 source/patterns/@aws-solutions-constructs/aws-events-rule-sns/test/events-rule-sns-topic.test.ts:255
 source/patterns/@aws-solutions-constructs/aws-eventbridge-sns/test/eventbridge-sns-topic.test.ts:255
-source/patterns/@aws-solutions-constructs/aws-events-rule-sqs/test/events-rule-sqs-queue.test.ts:131
-source/patterns/@aws-solutions-constructs/aws-eventbridge-sqs/test/eventbridge-sqs-queue.test.ts:131
+source/patterns/@aws-solutions-constructs/aws-events-rule-sqs/test/events-rule-sqs-queue.test.ts:143
+source/patterns/@aws-solutions-constructs/aws-eventbridge-sqs/test/eventbridge-sqs-queue.test.ts:143
 source/patterns/@aws-solutions-constructs/aws-dynamodb-stream-lambda/test/dynamodb-stream-lambda.test.ts:105
 source/patterns/@aws-solutions-constructs/aws-dynamodbstreams-lambda/test/dynamodbstreams-lambda.test.ts:105
 source/patterns/@aws-solutions-constructs/aws-apigateway-iot/README.md:39

Diff for: source/patterns/@aws-solutions-constructs/aws-eventbridge-lambda/README.md

@@ -69,7 +69,7 @@ _Parameters_
 
 | **Name**     | **Type**        | **Description** |
 |:-------------|:----------------|-----------------|
-|eventBus|[`events.IEventBus`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-events.IEventBus.html)|Returns the instance of events.IEventBus used by the construct|
+|eventBus?|[`events.IEventBus`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-events.IEventBus.html)|Returns the instance of events.IEventBus used by the construct|
 |eventsRule|[`events.Rule`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-events.Rule.html)|Returns an instance of events.Rule created by the construct|
 |lambdaFunction|[`lambda.Function`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-lambda.Function.html)|Returns an instance of lambda.Function created by the construct|
 

Diff for: source/patterns/@aws-solutions-constructs/aws-eventbridge-sns/README.md

@@ -80,7 +80,7 @@ _Parameters_
 
 | **Name**     | **Type**        | **Description** |
 |:-------------|:----------------|-----------------|
-|eventBus|[`events.IEventBus`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-events.IEventBus.html)|Returns the instance of events.IEventBus used by the construct|
+|eventBus?|[`events.IEventBus`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-events.IEventBus.html)|Returns the instance of events.IEventBus used by the construct|
 |eventsRule|[`events.Rule`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-events.Rule.html)|Returns an instance of events.Rule created by the construct|
 |snsTopic|[`sns.Topic`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-sns.Topic.html)|Returns an instance of sns.Topic created by the construct|
 |encryptionKey?|[`kms.Key`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-kms.Key.html)|Returns an instance of kms Key used for the SNS Topic.|

Diff for: source/patterns/@aws-solutions-constructs/aws-eventbridge-sqs/README.md

@@ -67,6 +67,8 @@ _Parameters_
 
 | **Name**     | **Type**        | **Description** |
 |:-------------|:----------------|-----------------|
+|existingEventBusInterface?|[`events.IEventBus`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-events.IEventBus.html)| Optional user-provided custom EventBus for construct to use. Providing both this and `eventBusProps` results an error.|
+|eventBusProps?|[`events.EventBusProps`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-events.EventBusProps.html)|Optional user-provided properties to override the default properties when creating a custom EventBus. Setting this value to `{}` will create a custom EventBus using all default properties. If neither this nor `existingEventBusInterface` is provided the construct will use the `default` EventBus. Providing both this and `existingEventBusInterface` results an error.|
 |eventRuleProps|[`events.RuleProps`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-events.RuleProps.html)|User provided eventRuleProps to override the defaults. |
 |existingQueueObj?|[`sqs.Queue`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-sqs.Queue.html)|An optional, existing SQS queue to be used instead of the default queue. Providing both this and `queueProps` will cause an error.|
 |queueProps?|[`sqs.QueueProps`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-sqs.QueueProps.html)|User provided props to override the default props for the SQS Queue. |
@@ -82,6 +84,7 @@ _Parameters_
 
 | **Name**     | **Type**        | **Description** |
 |:-------------|:----------------|-----------------|
+|eventBus?|[`events.IEventBus`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-events.IEventBus.html)|Returns the instance of events.IEventBus used by the construct|
 |eventsRule|[`events.Rule`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-events.Rule.html)|Returns an instance of events.Rule created by the construct|
 |sqsQueue|[`sqs.Queue`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-sqs.Queue.html)|Returns an instance of sqs.Queue created by the construct|
 |encryptionKey?|[`kms.Key`](https://docs.aws.amazon.com/cdk/api/latest/docs/@aws-cdk_aws-kms.Key.html)|Returns an instance of kms Key used for the SQS queue.|

Diff for: source/patterns/@aws-solutions-constructs/aws-eventbridge-sqs/lib/index.ts

@@ -24,72 +24,85 @@ import { overrideProps } from '@aws-solutions-constructs/core';
  * @summary The properties for the EventbridgeToSqs Construct
  */
 export interface EventbridgeToSqsProps {
+  /**
+   * Existing instance of a custom EventBus.
+   *
+   * @default - None
+   */
+  readonly existingEventBusInterface?: events.IEventBus;
+  /**
+   * A new custom EventBus is created with provided props.
+   *
+   * @default - None
+   */
+  readonly eventBusProps?: events.EventBusProps;
   /**
    * User provided eventRuleProps to override the defaults
    *
    * @default - None
    */
-  readonly eventRuleProps: events.RuleProps
+  readonly eventRuleProps: events.RuleProps;
   /**
    * Existing instance of SQS queue object, providing both this and queueProps will cause an error.
    *
    * @default - None
    */
-  readonly existingQueueObj?: sqs.Queue,
+  readonly existingQueueObj?: sqs.Queue;
   /**
    * User provided props to override the default props for the SQS queue.
    *
    * @default - Default props are used
    */
-  readonly queueProps?: sqs.QueueProps,
+  readonly queueProps?: sqs.QueueProps;
   /**
    * Whether to grant additional permissions to the Lambda function enabling it to purge the SQS queue.
    *
    * @default - "false", disabled by default.
    */
-  readonly enableQueuePurging?: boolean,
+  readonly enableQueuePurging?: boolean;
   /**
    * Optional user provided properties for the dead letter queue
    *
    * @default - Default props are used
    */
-  readonly deadLetterQueueProps?: sqs.QueueProps,
+  readonly deadLetterQueueProps?: sqs.QueueProps;
   /**
    * Whether to deploy a secondary queue to be used as a dead letter queue.
    *
    * @default - true.
    */
-  readonly deployDeadLetterQueue?: boolean,
+  readonly deployDeadLetterQueue?: boolean;
   /**
    * The number of times a message can be unsuccessfully dequeued before being moved to the dead-letter queue.
    *
    * @default - required field if deployDeadLetterQueue=true.
    */
-  readonly maxReceiveCount?: number,
+  readonly maxReceiveCount?: number;
   /**
    * Use a KMS Key, either managed by this CDK app, or imported. If importing an encryption key, it must be specified in
    * the encryptionKey property for this construct.
    *
    * @default - true (encryption enabled, managed by this CDK app).
    */
-  readonly enableEncryptionWithCustomerManagedKey?: boolean
+  readonly enableEncryptionWithCustomerManagedKey?: boolean;
   /**
    * An optional, imported encryption key to encrypt the SQS queue, and SNS Topic.
    *
    * @default - not specified.
    */
-  readonly encryptionKey?: kms.Key
+  readonly encryptionKey?: kms.Key;
   /**
    * Optional user-provided props to override the default props for the encryption key.
    *
    * @default - Default props are used.
    */
-  readonly encryptionKeyProps?: kms.KeyProps
+  readonly encryptionKeyProps?: kms.KeyProps;
 }
 
 export class EventbridgeToSqs extends Construct {
   public readonly sqsQueue: sqs.Queue;
   public readonly deadLetterQueue?: sqs.DeadLetterQueue;
+  public readonly eventBus?: events.IEventBus;
   public readonly eventsRule: events.Rule;
   public readonly encryptionKey?: kms.IKey;
 
@@ -136,7 +149,13 @@ export class EventbridgeToSqs extends Construct {
       })
     };
 
-    const defaultEventsRuleProps = defaults.DefaultEventsRuleProps([sqsEventTarget]);
+    // build an event bus if existingEventBus is provided or eventBusProps are provided
+    this.eventBus = defaults.buildEventBus(this, {
+      existingEventBusInterface: props.existingEventBusInterface,
+      eventBusProps: props.eventBusProps
+    });
+
+    const defaultEventsRuleProps = defaults.DefaultEventsRuleProps([sqsEventTarget], this.eventBus);
     const eventsRuleProps = overrideProps(defaultEventsRuleProps, props.eventRuleProps, true);
 
     this.eventsRule = new events.Rule(this, 'EventsRule', eventsRuleProps);