Yet another serverless solution for invoking AWS Lambda at a sub-minute frequency

// src/sender.js
const AWS = require(“aws-sdk”);

const sqs = new AWS.SQS({
  apiVersion: “2012-11-05”,
  region: process.env.AWS_REGION || “us-east-1”,
});

/**
* Generate delay seconds by an interval value.
*
* @example
* // returns [ 0, 30 ]
* generateDelaySeconds(30)
* // returns [ 0, 20, 40 ]
* generateDelaySeconds(20)
* // returns [ 0, 15, 30, 45 ]
* generateDelaySeconds(15)
* // returns [ 0, 10, 20, 30, 40, 50 ]
* generateDelaySeconds(10)
*/
const generateDelaySeconds = (interval) => {
  const numElem = Math.round(60 / interval);
  const array = Array.apply(0, Array(numElem + 1)).map((_, index) => {
    return index;
  });
  const min = Math.min(…array);
  const max = Math.max(…array);
  return array
    .map((a) => Math.round(((a – min) / (max – min)) * 60))
    .filter((a) => a < 60);
};

const handler = async () => {
  const interval = process.env.SCHEDULE_INTERVAL || 30;
  const delaySeconds = generateDelaySeconds(interval);
  for (const ds of delaySeconds) {
    const params = {
      MessageBody: JSON.stringify({ delaySecond: ds }),
      QueueUrl: process.env.QUEUE_URL,
      DelaySeconds: ds,
    };
    await sqs.sendMessage(params).promise();
  }
  console.log(`send messages, delay seconds – ${delaySeconds.join(“, “)}`);
};

module.exports = { handler };

// src/consumer.js
const sleep = (ms) => {
  return new Promise((resolve) => {
    setTimeout(resolve, ms);
  });
};

const handler = async (event) => {
  for (const rec of event.Records) {
    const body = JSON.parse(rec.body);
    console.log(`delay second – ${body.delaySecond}`);
    await sleep(1000);
  }
};

module.exports = { handler };