The Serverless Way

Serverless applications feel different and you need know why! In this talk I will look at how to design your application the serverless way.

The session will discuss how serverless applications embrace cloud services and live in a world where there are many separate parts, each responsible to for one thing. I'll cover the architectural patterns we use to design a serverless application including handling their stateless nature, how to use multiple functions for a task and leveraging event processing to trigger further functions. I will then turning my attention to showing you how to put these into practice by looking at how they can be implemented in an Apache OpenWhisk application.

By the end of the session, you'll be well placed to design and build your own serverless apps that take full advantage of the decentralised world they live in.

Presented TopConf, Tallinn, November 2018

Transcript

1. The Serverless Way Rob Allen November 2018
2. Deployment options 1. Physical servers 2. Virtual machines 3. Containers Rob Allen ~ @akrabat
3. Container deployments 1. Platform (e.g. Kubernetes) 2. Application (e.g. Cloud Foundry) 3. Serverless (e.g. OpenWhisk) Rob Allen ~ @akrabat
4. Serverless? The first thing to know about serverless computing is that "serverless" is a pretty bad name to call it. - Brandon Butler, Network World Rob Allen ~ @akrabat
5. AKA: Functions as a Service • Code • Deployed to the cloud • Executed in response to an event • On-demand scaling • Pay for execution, not when idle Rob Allen ~ @akrabat
6. Use-cases Synchronous Service is invoked and provides immediate response (HTTP requests: APIs, chat bots) Rob Allen ~ @akrabat
7. Use-cases Synchronous Service is invoked and provides immediate response (HTTP requests: APIs, chat bots) Asynchronous Push a message which drives an action later (web hooks, timed events, database changes) Rob Allen ~ @akrabat
8. Use-cases Synchronous Service is invoked and provides immediate response (HTTP requests: APIs, chat bots) Asynchronous Push a message which drives an action later (web hooks, timed events, database changes) Streaming Continuous data flow to be processed Rob Allen ~ @akrabat
9. Benefits • No need to think about servers • Concentrate on application code • Pay only for what you use, when you use it • Language agnostic: • NodeJS, Python, Swift, Go, Java, C#, PHP, Ruby, etc Rob Allen ~ @akrabat
10. Challenges • Start up latency • Time limit • State is external • DevOps is still a thing Rob Allen ~ @akrabat
11. It's about value Rob Allen ~ @akrabat
12. When should you use serverless? • Occasional server needs on a static site • Variable traffic levels • Additional compute without extending current platform • Responding to web hooks • Any web app that you want to be cheaper to run! Rob Allen ~ @akrabat
13. Serverless providers Rob Allen ~ @akrabat
14. Hello World AWS Lambda: def my_handler(event, context): name = event.get("name", "World") message = 'Hello {}!'.format(name) return {'message': message} Rob Allen ~ @akrabat
15. Hello World Apache OpenWhisk: def main(args): name = args.get("name", "World") message = 'Hello {}!'.format(name) return {'message': message} Rob Allen ~ @akrabat
16. Hello World Google Cloud Functions def hello_http(request): name = request.json.get("name", "World") message = 'Hello {}!'.format(name) return message Rob Allen ~ @akrabat
17. Hello World Azure Cloud Functions import azure.functions as func def main(req: func.HttpRequest, msg: func.Out[func.QueueMessage]) -> str: name = req.params.json.get("name", "World") message = 'Hello {}!'.format(name) msg.set(message) return message Rob Allen ~ @akrabat
18. Apache OpenWhisk Rob Allen ~ @akrabat
19. Concepts Rob Allen ~ @akrabat
20. The anatomy of an action def main(args): # Marshall inputs from event parameters name = args.get("name", "World") # Do the work message = 'Hello {}!'.format(name) # return result return {'message': message} Rob Allen ~ @akrabat
21. The anatomy of an action def main(args): # Marshall inputs from event parameters name = args.get("name", "World") # Do the work message = 'Hello {}!'.format(name) # return result return {'message': message} Rob Allen ~ @akrabat
22. The anatomy of an action def main(args): # Marshall inputs from event parameters name = args.get("name", "World") # Do the work message = 'Hello {}!'.format(name) # return result return {'message': message} Rob Allen ~ @akrabat
23. The anatomy of an action def main(args): # Marshall inputs from event parameters name = args.get("name", "World") # Do the work message = 'Hello {}!'.format(name) # return result return {'message': message} Rob Allen ~ @akrabat
24. Creating your action in OpenWhisk $ wsk action create hello hello.py ok: updated action hello Rob Allen ~ @akrabat
25. Running your action in OpenWhisk $ wsk action create hello hello.py ok: updated action hello $ wsk action invoke hello --result --param name Rob Rob Allen ~ @akrabat
26. Running your action in OpenWhisk $ wsk action create hello hello.py ok: updated action hello $ wsk action invoke hello --result --param name Rob { "message": "Hello Rob!" } Rob Allen ~ @akrabat
27. Access from the web API Gateway provides: • API routing • Rate limiting • Authentication • Custom domains Rob Allen ~ @akrabat
28. API Gateway Rob Allen ~ @akrabat
29. API Gateway $ wsk api create /myapp /hello GET hello Rob Allen ~ @akrabat
30. API Gateway $ wsk api create /myapp /hello GET hello ok: created API /myapp/hello GET for action /_/hello Rob Allen ~ @akrabat
31. API Gateway $ wsk api create /myapp /hello GET hello ok: created API /myapp/hello GET for action /_/hello $ curl https://example.com/myapp/hello?name=Rob Rob Allen ~ @akrabat
32. API Gateway $ wsk api create /myapp /hello GET hello ok: created API /myapp/hello GET for action /_/hello $ curl https://example.com/myapp/hello?name=Rob { "message": "Hello Rob!" } Rob Allen ~ @akrabat
33. Event providers (feeds) • Webhook triggers: • GitHub • Slack • Databases: CouchDB • Message Queues: Kafka • Mobile Push • Scheduled Rob Allen ~ @akrabat
34. Architecture Rob Allen ~ @akrabat
35. Monolith architecture Rob Allen ~ @akrabat
36. Serverless architecture Rob Allen ~ @akrabat
37. Serverless architecture pattern Rob Allen ~ @akrabat
38. Functions are key Rob Allen ~ @akrabat
39. Functions are the Unit of Deployment Rob Allen ~ @akrabat
40. Functions are the Unit of Scale Rob Allen ~ @akrabat
41. Functions are Stateless Rob Allen ~ @akrabat
42. Functions have Structure Rob Allen ~ @akrabat
43. Structure If it's non-trivial, software engineering principles apply! • Use multiple methods Rob Allen ~ @akrabat
44. Structure If it's non-trivial, software engineering principles apply! • Use multiple methods • Use multiple files Rob Allen ~ @akrabat
45. Structure If it's non-trivial, software engineering principles apply! • Use multiple methods • Use multiple files • Integrate reusable dependencies Rob Allen ~ @akrabat
46. Separation Separate the action handler from your business logic Rob Allen ~ @akrabat
47. Separation Separate the action handler from your business logic Rob Allen ~ @akrabat
48. Example from Adobe CIF-Magento function postCoupon(args) { const validator = new InputValidator(args, ERROR_TYPE) .checkArguments().mandatoryParameter('id') if (validator.error) { return validator.buildErrorResponse(); } const cart = new MagentoCart(args, cartMapper.mapCart, 'guestcart'); return cart.byId(args.id).addCoupon(args.code).then(function () { return cart.byId(args.id).get(); }).catch(error => { return cart.handleError(error); }); } Rob Allen ~ @akrabat
49. Example from Adobe CIF-Magento function postCoupon(args) { const validator = new InputValidator(args, ERROR_TYPE) .checkArguments().mandatoryParameter('id') if (validator.error) { return validator.buildErrorResponse(); } const cart = new MagentoCart(args, cartMapper.mapCart, 'guestcart'); return cart.byId(args.id).addCoupon(args.code).then(function () { return cart.byId(args.id).get(); }).catch(error => { return cart.handleError(error); }); } Rob Allen ~ @akrabat
50. Example from Adobe CIF-Magento function postCoupon(args) { const validator = new InputValidator(args, ERROR_TYPE) .checkArguments().mandatoryParameter('id') if (validator.error) { return validator.buildErrorResponse(); } const cart = new MagentoCart(args, cartMapper.mapCart, 'guestcart'); return cart.byId(args.id).addCoupon(args.code).then(function () { return cart.byId(args.id).get(); }).catch(error => { return cart.handleError(error); }); } Rob Allen ~ @akrabat
51. Example from Adobe CIF-Magento function postCoupon(args) { const validator = new InputValidator(args, ERROR_TYPE) .checkArguments().mandatoryParameter('id') if (validator.error) { return validator.buildErrorResponse(); } const cart = new MagentoCart(args, cartMapper.mapCart, 'guestcart'); return cart.byId(args.id).addCoupon(args.code).then(function () { return cart.byId(args.id).get(); }).catch(error => { return cart.handleError(error); }); } Rob Allen ~ @akrabat
52. Serverless state machines Rob Allen ~ @akrabat
53. Serverless state machines Rob Allen ~ @akrabat
54. Rob Allen ~ @akrabat
55. Rob Allen ~ @akrabat
56. Infrastructure as Code composer.sequence( composer.if( 'binday/authenticate', composer.if( 'binday/validate', composer.if( 'binday/is_intent_setday', 'binday/set_bin_day', 'binday/get_next_bin_day' ), 'binday/send_failure' ), 'binday/send_failure' ), 'binday/format_output_for_alexa' ) Rob Allen ~ @akrabat
57. Tips & tricks • Make troubleshooting easier: • Ability to disable event triggers • Identifiers that run throughout functions for a single "operation" • Don't forget HTTP circuit breakers - retry with a back-off algorithm • Tune memory settings for each function - affects price (& performance) Rob Allen ~ @akrabat
58. To sum up Rob Allen ~ @akrabat
59. Thank you! Rob Allen ~ @akrabat