Serverless Microservices are the New Black

Looking at a simple example of a microservice (nanoservice?) built with API Gateway and Apache OpenWhisk

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1. Serverless Microservices Are The New Black Lorna Mitchell, IBM
2. Serverless FaaS: Functions as a Service • write a function (many languages supported) • deploy it to the cloud (Lambda, Cloud Functions, etc) • only pay while the function is running (charged per GBsec) • your platform scales on demand @lornajane
3. When To Go Serverless • To create a small, scalable application (focussed API, microservices) • For occasional server needs (contact form on static site) • To provide compute power (processing quantities of data) • To move heavy lifting off web platform (classic example: PDF generation) @lornajane
4. FaaS + HTTP = Microservices! @lornajane
5. Microservices Microservices are: • small and modular • loosely coupled • independently developed and deployed • great for building components • decentralised ... they are basically small HTTP APIs @lornajane
6. Microservice Design Points I prefer RESTful-ish APIs • Status codes are important • Headers are for metadata • URLs and verbs together define what happens • All endpoints are stateless • SSL is required @lornajane
7. Lorna's Plans Service Keep a list of my travel plans, with locations and dates. Use a serverless platform (IBM Cloud Functions) and PostgreSQL GET /plans list all plans GET /plans/42 show one plan POST /plans create a new plan DELETE /plans/42 delete a plan @lornajane
8. Lorna's Plans Service @lornajane
9. Creating the Microservices @lornajane
10. Creating the Microservices @lornajane
11. Writing Serverless Functions • Small, self-contained units of functionality • Run on-demand in response to an event • Incoming parameters can include • event information • parameters set at deploy time • connection info for other services @lornajane
12. Make Plans: the Code 1 const pgp = require('pg-promise')(); 2 function main(params) { 3 var postgres_url = params['__bx_creds']['compose-for-postgresql']['uri']; 4 var base_url = params['__ow_headers']['x-forwarded-url']; 5 return new Promise(function(resolve, reject) { 6 db = pgp(postgres_url, []); 7 8 db.one("INSERT INTO plans (location, travel_date) VALUES 9 ($1, $2) RETURNING plan_id", 10 [location, travel_date]) 11 .then(function(data) { 12 var redirect_to = base_url + "/" + data.plan_id; 13 resolve({headers: {"Location": redirect_to}, 14 statusCode: 303}) 15 }) @lornajane
13. Prepare to Deploy: package In OpenWhisk, there are "packages". These let us: • group actions together • add parameters to a package that will be available to all actions From the deployment script, the line to create plans-api: ibmcloud wsk package update plans-api @lornajane
14. Prepare to Deploy: services The function needs to connect to the database. We can bind the database to the package to achieve this: ibmcloud wsk service bind compose-for-postgresql plans-api @lornajane
15. Prepare to Deploy: libraries To include extra libraries, we can: • create package.json and run npm install • zip up index.js and node_modules into a zip file • deploy the zip file, and include runtime instructions cd write-plan zip -rq write-plan.zip index.js node_modules @lornajane
16. Make Plans: Deploy We're ready! Push the action to the cloud: ibmcloud wsk action update --kind nodejs:8 --web raw \ plans-api/write-plan write-plan.zip @lornajane
17. Make Plans: API Gateway To have this action repsond to our HTTP request, set up the API Gateway: • create the API • set up the path, verb and action to link together ibmcloud wsk api create /plans GET plans-api/get-plans \ --response-type http @lornajane
18. Creating the Microservices @lornajane
19. Calling The Endpoint Quick example with cURL (other clients available): $ curl -L -H "Content-Type: application/json" \ https://service.eu.apiconnect.ibmcloud.com/.../plans \ -d '{"location": "Turin", "travel_date": "2018-04-11"}' { "plans": [{ "plan_id": 3, "travel_date": "2018-04-11T00:00:00.000Z", "location": "Turin" }] } @lornajane
20. Microservices: Security @lornajane
21. Security In web console: https://console.bluemix.net/openwhisk/apimanagement @lornajane
22. Security In web console: https://console.bluemix.net/openwhisk/apimanagement @lornajane
23. Project Structure Many possible approaches, this is mine: . ├── deploy.sh ├── get-plans │ ├── index.js │ ├── node_modules │ ├── package-lock.json │ └── package.json └── write-plan ├── index.js ├── node_modules ├── package-lock.json └── package.json @lornajane
24. Deployment Using https://travis-ci.com/ • deploy with a script • script downloads ibmcloud tool and cloud-functions plugin • set an API key as an environment variable • then run commands (see deploy.sh in GitHub project) @lornajane
25. Serverless Microservices @lornajane
26. Serverless Ideal for working with many small parts Apache OpenWhisk paired with API Gateway: perfect candidate for microservices @lornajane
27. Microservices Service Oriented Architecture is alive and well • microservices expose endpoints • they share reusable components • specific components guard access to services/datastores • each component can be separately developed, tested and deployed @lornajane
28. Resources • Code: https://github.com/lornajane/plans-microservice • Apache OpenWhisk: http://openwhisk.apache.org • IBM Cloud Functions: https://www.ibm.com/cloud/functions • My blog: https://lornajane.net @lornajane