Microservices @BlaBlaCar

A presentation about microservices at BlaBlaCar.

Talk given at sfPot March 2015 at SensioLabs

Transcript

1. Microservices @BlaBlaCar
2. Olivier Dolbeau @odolbeau Web Architect About me
4. What’s the v3? • after the v2 (thanks cap’tain obvious!) • Full sf2 application • contains EVERYTHING ◦ web ◦ admin ◦ workers ◦ dead code ◦ ...
5. 18 août 2011 First commit 6 days after: Steve Jobs resigns as the CEO of Apple Inc.
7. Thanks v3 • Pragmatic! • Everything in the same place • only one application to deploy • only one application to explain to newcomers (even if a lot of time is needed to understand everything) It was a good choice at this moment.
8. Figures
9. 340 494 NLOC There is “only” 268 041 NLOC for symfony/symfony
10. 24 906 Commits There is “only” 15 506 commits for symfony/symfony There is “only” 10 228 commits for joyent/node There is “only” 9 266 commits for twbs/bootstrap There is 44 809 commits for rails/rails (but it’s ruby… #troll)
11. 53 Contributors
13. 3 537 Tests There is “only” 17 593 tests for symfony/symfony… #ohwait
14. 30 minutes to run them all 28 minutes for symfony/symfony… #fake
15. 20 minutes to deploy
17. Problems of a very huge code base • Very (VERY) Hard to maintain • Deployment process (including tests) is too long
18. “With minor change comes major bugs” Myself, based on my personal experience.
19. Let’s do it again! V4? No!
21. Microservices The new developer silver bullet! #troll
22. Definition “In computing, microservices is a software architecture design pattern, in which complex applications are composed of small, independent processes communicating with each other using language-agnostic APIs. These services are small, highly decoupled and focus on doing a small task.” You know from where comes this definition
23. How? Workers first. • mail • sms • user-action • … We now have 60+ workers in… 60+ git repositories.
24. Pros • easy to: ◦ understand ◦ write / launch tests ◦ deploy • always the same code base: ◦ same command to consume ◦ same deployment script ◦ … • We made OSS: swarrot/swarrot
25. Cons • process: ◦ new repo ◦ new build plan in bamboo ◦ a bit of chef for deployment • new side projects: ◦ to configure our broker (Rabbit) ◦ to deal with configuration • increase ops complexity
28. Think global! • Multi DC. \o/ • Need to split data across the world. • Need to shard data.
29. But how to achieve this when you don’t even know how your application works?
30. How to shard users? You gonna hate Doctrine ORM. You gonna hate all your listeners. You gonna hate everyone.
31. Enter the gateway!
32. Goals • identify & isolate the business logic • identify & isolate data calls • without rewriting the whole application • without impacting the actual delivery • must be usable everywhere (not only in our main application) Do what we want with our data and our business
33. Implementation Strict separation of concerns • business • data One repository for everything • tried with more => complex for development • still easily splittable
35. Data • 1 interface. Can have several implementations. • easy to ◦ add cache ◦ change backend ◦ shard data • Strict rules: ◦ findOne* => return an array or throw exception ◦ findBy* => return an Adapter ◦ ...
36. • Lots of entry points! (called “action”) • Request / Response / Handler pattern • Flat request / response => no objects. \o/ • can call 0-n times the data layer. Business
39. • concise • event dispatched into RabbitMQ • We always have a response object or an exception. No more null everywhere. \o/
40. Pros • Separation of concern • The ability to isolate anything! • strict rules (exceptions & co) • easy to understand
41. Cons • versioning • applications updates • new side projects (again) ◦ to deal with fixtures • kind of duplicate code
42. Cassandra for messaging User sharding Rating data isolation
45. Facts • Need to deploy the whole application • 1 bundle • 54 controllers • 36 957 NLOC • Lot of shared code • Can break the website
46. Goal • Several independent applications • Centralized application to handler permissions / connection • A bit like SensioConnect for all Sensio products
47. I hope...
49. The silver bullet doesn’t exist! Microservices comes with several drawbacks but it is worth it! We will continue to move forward We need your help! ;)