Vanilla CDK handler example

handler.js

// manually create the AWS client, look up environment variables etc.
const AWS = require('aws-sdk');

const sns = new AWS.SNS();

const topicArn = process.env.TOPIC_ARN;
if (!topicArn) {
  throw new Error('TOPIC_ARN must be defined');
}

export async function handler() {
  await sns.publish({
    // serialization is manual
    Message: JSON.stringify({
      key: 'some key',
      count: 1,
      timestamp: new Date().toISOString()
    }),
    // topic ARN must be defined manually also
    TopicArn: topicArn
  })
}

See the CDK application: https://gist.github.com/sam-goodwin/77f6650ef67ad93e5aa97cc38458ca2e