Golang @ eureka Masashi Salvador Mitsuzawa

about eureka - pairs - over 3,500,000 users - Japan & Taiwan 12೥9݄ 13೥3݄ 13೥9݄ 14೥3݄ 14೥9݄ 15೥3݄ 225ສ 135ສ 45ສ 90ສ 190ສ 3.5 year over 3,500,000

- Members - 50 engineers - 54 non engineers

about me - Masashi Salvador Mitsuzawa - Senior Engineer @ eureka - Monetization Team Leader / Server Side Engineer Leader - Love #Curry #Haskell #Golang #Algorithm #MachineLearning - see : #ΧϨʔ৯͏ͨΊʹੜ͖ͯΔ @instagram - Twitter: @MasashiSalvador - Major : Computational Neuroscience @ Graduate School - 2013 - 2015 DeNA - 2015 - current eureka

Outline • Why Go? • Architecture of pairs • Microservices • Structure of application • Libraries • Golang TIPS in pairs

Outline • Why Go? • Architecture of pairs • Microservices • Structure of application • Libraries • Golang TIPS in pairs

pairs: - About pairs Go Project - Over 1 year project - Data migration (schema change) - Full-scratch the entire codebase - Background - huge tech debt (including design debt) - Monolith architecture - DB (unscalable / strange schema) - Tightly Coupled - Technical Challenge

Why Go? - Minimum syntax (minimum Spec)
 - bundle with formatter - easy to learn - able to keep clean codebase - easy to read! (important : able to read all OSS code) - Static Typing - Safe - High Performance - Concurrency - goroutine / channel - Good Standard Libraries (net/http, database/sql)

Why NOT Go? - No “Modern” Syntax - map / reduce - No Class syntax - No Exception - Less established Libraries and frameworks - WAF(gin? revel? beego? echo?) - testing - ORM

But We love - new language - challenging - creating new standard - at the same time engineers’ growing up

then we chose Go

Outline • Why Go? • Architecture of pairs • Microservices • Structure of application • Libraries • Golang TIPS in pairs

Microservices EJBHSBNESBXOCZ!LBOFTIJO

Microservices - Service Oriented Architecture (All written in Golang) - pairs.lv - admin - search - batch - payment - surveillance - Stack - gin(pairs.lv) / goji(payment) - Elasticsearch - MySQL - Redis(cache) / DynamoDB - Ansible(provision, build, deploy)

Response Request Structure Controller Facade Service Repository Entity - Basically structured as MVC Libraries View URL routing JSON SPA AngularJS + TypeScript DB

Response Request Structure Controller Facade Service Repository Entity - Basically structured as MVC Libraries View URL routing JSON SPA AngularJS + TypeScript DB Core Library

Libraries - WAF - revel (previous) - gin (current) - DB migration - goose - ORM - xorm - testing - ginkgo (RSpec Like / previous) - Go standard + testify (current) - package vendoring - nuts (previous) - glide (current)

Outline • Why Go? • Architecture of pairs • Microservices • Structure of application • Libraries • Golang TIPS in pairs

go generate - go generate

go generate - go generate

go generate - handing with routing - gin default (from README.md) - how to handle with many routing and controllers?

go generate - handing with routing - naively (like many WAFs) main.go config/route mapping URL -> controller - a way to realize it in Go generator/main.go routes/api_xxx_v1.tml api_yyy_v1.tml api_zzz_v1.tml Read Read app/main_gen.go routes_gen.go Generate

go generate - in routes_gen.go - generator/main.go: pattern written in go template

package vendoring - nuts (previous) eure/eure-go cloned from repositories pinned commit-hash app.go go get github.com/eure/eure-go
 import “github.com/eure/eure-go/ vendor/_nuts/github.com/revel/revel" import

package vendoring - glide (current) - glide get github.com/hogehoge/fugafuga - glide install

ginkgo -> standard library - Why NOT ginkgo? - heavy - Rspec Syntax - JustBeforeEach, BeforeEach, JustBefore, Before - not like Golang - members’ unfamiliar with RSpec - Standard testing + testify

Mines … - Default Values - Slice append - packaging (unfamiliar with LL lang users) - gophers love bare net/http too much :)

Thank you :)