Concept - Retrieve and process batches >10 messages from SQS

sqsBiggerBatching.js

let msgIdx = 0;
const randomInt = (min, max) => {
	return Math.floor(Math.random() * (max - min + 1) + min);
};
const getMessages = (batchSize) => {
	const messages = [];
	for (let i = 0; i < batchSize; i += 1) {
		messages.push({ idx: msgIdx, timeout: randomInt(0, 20) });
		msgIdx += 1;
	}
	return messages;
};

const sleep = (ms) => new Promise((r) => setTimeout(r, ms * 1000));
const doThing = async (msg) => {
	await sleep(msg.timeout);
	console.log(msg.idx, `done (${msg.timeout})`);
	return undefined;
};

const maxInFlight = 30;
let inFlight = 0;
const batchSize = 10;

(async () => {
	while (true) {
		console.log("inFlight:", inFlight);
		if (inFlight + batchSize <= maxInFlight) {
			const newMessages = getMessages(batchSize);
			for (const msg of newMessages) {
				doThing(msg)
					.then(() => (inFlight -= 1))
					.catch(() => (inFlight -= 1));
				inFlight += 1;
			}
		}
		//console.log("inFlight (after)", inFlight);
		await sleep(0.2);
	}
})();