SoundCloud migrated from a monolithic architecture to microservices using Finagle to address scalability issues as they were uploading 11 hours of audio per minute and serving 300 million users per month. They initially used Finagle with Finatra but found it inflexible so switched to building custom services and filters with Finagle directly. This allowed them to transition their traffic fully to Finagle-based microservices in about a month. While Finagle provided benefits, they still found some aspects like configuration and routing complex to use across many services.

1. Quick Report:
Finagle-Based Microservices
at SoundCloud
Phil Calçado
http://philcalcado.com
@pcalcado

4. > 11 hours of audio uploaded
every minute
~ 300 million people every month

5. Like everybody else
around that time…

6. Like everybody else
around that time…

7. Because ${reasons}, we
decided to break the
monolith. But how?

8. The Mothership
SoundCloud.com

9. The Mothership
Sounds ˝
& Sets
Social
Graph
Activity
Stream
Premium ˝
Features Search
API

10. Reminds me of something…

11. Monoliths exist when building
within it is cheaper than the
overhead associated with
coordination of multiple
components. !
!

12. We need an inexpensive
services framework

13. Realistic options

14. Summary in a picture

15. Phase 1: Finatra

17. Good stuff
• Model is very intuitive to people coming from other
languages
• Production-ready service in minutes

18. Main issues we had
• Not always on latest Finagle version
• Doesn't compose with Filters
• Internals aren’t very flexible
• twitter-server is too far away from our infra

19. Phase 2: Filters and Services

20. Where the gold was

21. We followed suit
(114 LOC)

22. Routes are defined in a
single file

23. Each controller is a
Service

24. Lots of filters

25. Today
• 100% Traffic hitting Finagle-based services
• Redis, memcached, MySQL drivers used in
production
• About one month to ramp-up non-Scala developers

26. What is still hard
• Config flags implementation isn't very flexible, we
use env vars not properties
• API surface space for Finagle is too large. What’s
user land, what’s test, what’s internal?
• Bespoke scatter-gather code all over our apps
• Every organization builds their own Finagle routing

27. Up next

28. Containers for
Continuous Delivery

29. Thrift/Protocol Buffers?
}
JSON parsing?

30. phil calçado
http://philcalcado.com
http://soundcloud.com/pcalcado
@pcalcado
www.soundcloud.com