[aws-lambda] Add "Topics" property to EventSourceMappingOptions

Lambda recently added support for MSK as an event source (https://aws.amazon.com/about-aws/whats-new/2020/08/aws-lambda-now-supports-amazon-managed-streaming-for-apache-kafka-as-an-event-source/), and there’s now a “Topics” property on the CloudFormation resource definition (https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-lambda-eventsourcemapping.html#cfn-lambda-eventsourcemapping-topics).

Use Case

Using Lambda simplifies reading data from Apache Kafka, as other options usually require customers to worry about infrastructure management.

Proposed Solution

Include topics as an optional parameter of EventSourceMappingOptions interface:

export interface EventSourceMappingOptions {
    /**
     * existing properties
     */

    /**
     * The name of the Kafka topic.
     * 
     * Valid range:
     * * Maximum value of 1 
     */
    readonly topics?: string[];
}

It’d then be used as:

lambdaFn.addEventSourceMapping('MSKTrigger', {
    eventSourceArn: 'arn:aws:kafka:us-east-1:123456789012:cluster/kafka-cluster/random-id',
    startingPosition: lambda.StartingPosition.LATEST,
    topics: ['my-topic']
});

Other

In the future, there could even be a MSKEventSource in the aws-lambda-event-sources package, but just adding the topics property should allow customers to get started.

• 👋 I may be able to implement this feature request
• ⚠️ This feature might incur a breaking change

---

This is a 🚀 Feature Request

[nija-at]

If I created the PR just adding the topics property, would that be rejected?

Definitely not. Feel free to post one.

[dscpinheiro]

@nija-at PR was created: https://github.com/aws/aws-cdk/pull/10445