Lambda alla spina

This deck presents the evolution of AWS Lambda, focusing on two major features designed to run standard applications with less architectural overhead. Web Functions allow developers to deploy unchanged HTTP web servers (like Express) directly to Lambda, supporting concurrent requests per environment and billing for active CPU. Durable Functions enable long-running, multi-step workflows to be written directly in code with automatic state checkpointing and zero compute costs during pauses.

Transcript

1. AWS UG Torino 2026 #2 · Oktoberfest Edition Lambda alla spina Web Functions e Durable Brews Francesco Lerro
2. 2014: run code on demand, own no server event λ result no servers · scale to zero · pay per request 2
3. Twelve years in production 12 years of the same battle-tested platform 2014 2018 2020 2022 2025 2026 launch Firecracker containers SnapStart durable web functions 3
4. Primo giro Web Functions your HTTP server, unchanged
5. Before Web Functions API Gateway λ DB two services to configure · one request per environment · billed while waiting 5
6. A plain Express app. No adapter. import express from 'express'; import db from './db.js'; const app = express(); const [host, port] = process.env.AWS_LAMBDA_HTTP_ENDPOINT.split(':'); app.get('/beer', async (req, res) => { const beer = await db.randomBeer(); //IO waiting res.json({‘🍺’: beer}); }); app.listen(port, host); ❯ aws lambda-web deploy --name beers --code . 6
7. DEMO 7
8. Many requests, one environment Event Functions req Web Functions environment req λ req req environment req req req environment 1 request per environment one environment up to 128 at once req up to 64 instances per region 9
9. Built for I/O-heavy web apps 1 URL CPU 512MB many Regions, nearest one serves billed when busy, not while waiting code + lib max size new deploy → new revision today: Node.js 24 · Arm64 · 5 Regions 10
10. On steady traffic, pay for CPU, not for waiting Event Functions Web Functions $740 $240 per month per month 100 req/s 8.6M req/day) · 200 ms per request, 20 ms of it CPU · Arm, us-east-1 CPU-heavy or tiny requests? Event Functions can still win 11
11. Secondo giro Durable Functions long-running workflows as plain code
12. Delayed payment def handler(event, ctx): funds = hold_funds(event) time.sleep(900) return charge(funds) 13
13. Before durable functions λ hold_funds wait 15 min λ charge 14
14. Step Functions workflow { λ hold_funds wait 15 min λ charge } "StartAt": "Charge", "States": { "Charge": { "Type": "Task", "Resource": "arn:aws:lambda:…:function:hold_funds", "Next": "Wait" }, "Wait": { "Type": "Wait", "Seconds": 1800, "Next": "Notify" }, "Notify": { "Type": "Task", "Resource": "arn:aws:lambda:…:function:charge", "End": true } } flow in JSON · logic in separate functions · two places to change 15
15. Sequential code def handler(event, ctx): funds = hold_funds(event) time.sleep(900) return charge(funds) 16
16. Sequential code, made durable @durable_execution def handler(event, ctx): funds = ctx.step(hold_funds(event)) ctx.wait(Duration.from_minutes(15)) return ctx.step(charge(funds)) 17
17. Sequential code, made durable step checkpoint + retry wait suspend, no compute callback wait for a human parallel / map @durable_execution def handler(event, ctx): funds = ctx.step(hold_funds(event)) ctx.wait(Duration.from_minutes(15)) return ctx.step(charge(funds)) fan out, join up to 1 year per execution 18
18. Replay skips completed steps run 1 run 2 A wait run sleep A wait B cached done run keep code outside steps deterministic 19
19. Durable Functions or Step Functions? Durable Functions Step Functions code-centric service-centric logic inside one service flows across services your language, your tests 220+ native integrations often both: durable inside, Step Functions between 20
20. Same Lambda, new shapes Web Event + durable HTTP apps & APIs, unchanged events & multi-step workflows one programming model also on tap: Lambda Managed Instances, Lambda MicroVMs 21
21. Prosit! Questions? Lambda Web Functions official docs Scaling for Lambda Web Functions serverlessland.com/explore/lambda-web-functions serverlessland.com/explore/lambda-durable-functions linkedin.com/in/lerro