Vanilla CDK application example

app.ts

import cdk = require('@aws-cdk/core');
import lambda = require('@aws-cdk/aws-lambda');
import sns = require('@aws-cdk/aws-sns');

import path = require('path');

const app = new cdk.App();
const stack = new cdk.Stack(app, 'my-stack');

const topic = new sns.Topic(stack, 'MyTopic');

const func = new lambda.Function(stack, 'MyFunction', {
  runtime: lambda.Runtime.NODEJS_10_X,
  handler: 'index.handler',
  code: lambda.Code.asset(path.join(__dirname, 'handlers')),
  environment: {
    TOPIC_ARN: topic.topicArn
  }
});

topic.grantPublish(func);

See the handler code: https://gist.github.com/sam-goodwin/2681554480c32c0498544eae5765333e