This document discusses Gett's location service, which maintains the geographical location of drivers. It describes the challenges of scaling, stability, and handling real-time data. The service has evolved from using Rails and Node.js to being rewritten in Golang using Redis for caching. The latest implementation uses Pat, Negroni and Redis. It generates code and uses MessagePack for serialization. Golang has helped Gett with scaling services like metrics and reporting and more services are moving to a dual Golang/other language stack.

1. Gett &
Golang
Sergey Lanzman
February 2016

2. About Gett

3. Challenges
1. Scale
1. Stability
1. Time to Market
1. Big Data
1. Real Time data

4. Tech stack

5. Challenges

6. Location service
Responsibility: maintain
geographical location of
drivers (with short history) +
allow query.

7. Location service
History
1. Rails + MySQL
1. Node.js + MongoDB
1. Golang + MongoDB
1. Golang + Redis - MongoDB

8. Location service
1. Rewrite from Node.js
to Golang as is.
2. Add in-memory cache
and Redis.
3. Move geospatial from MongoDB to Golang code.
4. Additional modules: Amazon Kinesis integration and
etc.

9. Location service
First implementation
1. Martini + mgo + redigo
2. Hundreds of goroutines for async write.
web/martini
X 150-300
X 150-300
X 150-300

10. Location service
web
Latest implementation
1. Pat + negroni + redigo.
MessagePack

11. Location service
Last implementations
1. Build Kd-trees Every second for geospatial
geo-module(KD-Tree)
X4every 1 second
web

12. Location service
Monitoring tools
1. StackDriver - only server metrics
2. NewRelic - no official support, but there are plugins
(available). Now implement with CGO + agent SDK

13. Location service

14. Location service

15. Location service

16. Location service
Generating code + MessagePack
https://github.com/tinylib/msgp
https://github.com/alecthomas/go_serialization_benchmarks

17. Location service
Code generate + MessagePack
https://github.com/tinylib/msgp

18. Location service
Dependencies:
1. github.com/bmizerany/pat
2. github.com/codegangsta/negroni
3. github.com/garyburd/redigo/redis
4. github.com/gorilla/context
5. github.com/manveru/faker
6. github.com/remind101/newrelic
7. github.com/spf13/viper
8. github.com/tinylib/msgp/msgp
9. gopkg.in/airbrake/gobrake.v2
10.github.com/facebookgo/grace/gracehttp
11.github.com/sendgridlabs/go-kinesis
12.github.com/go-lang-plugin-org/go-lang-idea-plugin

19. Golang && Gett
Dual stack

20. Golang && Gett
Other services on golang
1. Relay metrics
2. Report service (dual stack)
3. Fleets service
4. Dispatching service (in development)
5. Billing (future)
6. API gateway (future)
More services move to dual stack

21. THANK YOU