Talk at Kuberton, 02/03/2019 Monolith vs Microservices with Golang at practice - Ivan Kutuzov, Tech Lead at SoftServe

1. Monolith vs Microservices with
Golang at Practice
Ivan Kutuzov, SoftServe, #GolangUA

2. Agenda:
- Quick introduction to GO
- How to create monolith app
- How to create microservice
- What a difference

3. Go pros
● Fast compilation
● Simplicity
● Memory safe
● Efficiency
● Concurrency
● Network oriented

4. Guiding principles
● Simplicity
● Readability
● Productivity

5. Monolith

6. Maintainability
● Changes in one area of an application should affect
as few other places as possible
● Adding features should not require large code-base
changes
● Adding new ways to interact with the application
should require as few changes as possible
● Debugging should require as few work-arounds and
"just this once" hacks as possible
● Testing should be relatively easy
https://dave.cheney.net/practical-go/presentations/qcon-china.html

7. Hexagonal Architecture/ Clean Architecture / Port and Adapters
● Entity
● Value Object
● Domain Event
● Aggregate
● Service
● Repository

8. Where read more
● Kat Zien: How Do You Structure Your Go Apps
● Peter Bourgon: Go for Industrial Programming
● Ben Johnson: Standard Package Layout
● Marcus Olsson: gh: marcusolsson/goddd

9. Existing frameworks & tools
https://github.com/speedwheel/awesome-go-web-frameworks/blob/master/README.md

10. Existing frameworks & tools
● Router: Named Path Parameters & Wildcard, Regex,
Grouping, Custom HTTP Errors, Auto Docs
● Middleware ecosystem
● Server: Automatic HTTPS, Gracefully Shutdown,
Multi listeners, Sessions, Websockets, Files
● View Engines
● Renderer, Caching
● Security, Authentication
● Logging, Metrics

11. Microservice

12. Microservices design principles
● Single purpose
● Loose coupling
● High cohesion
● Is not a service in small number of lines of code
● Is not a service that is built with new technology
● Is not a service that has to be built from scratch

13. Microservices design principles
https://medium.engineering/microservice-architecture-at-medium-9c33805eb74f

14. Go microservice toolkits statistics rating
● The most popular project is go-kit/kit
● The newest project is NYTimes/gizmo
● The project with more commits is koding/kite
● The project with biggest average contribution period is rsms/gotalk
● The project with more tags is micro/go-micro
● The project made by most notable top contributors is koding/kite
● The project with best errors resolving rate is micro/go-micro
● The project with more commits by day is koding/kite
● The project with the most active number of forkers is NYTimes/gizmo
● The project with biggest number of returning contributors is go-kit/kit
https://docs.google.com/spreadsheets/d/1d0WcI5ahmJdysyyHeZB9CVlolXF027UlY1fTPbyiFCE/edit?usp=sharing

15. Go microservice toolkits features
● Service Discovery
● Load Balancing
● Message Encoding
● Request / Response
● Async Messaging
● Pluggable Interfaces
https://github.com/micro/go-micro#features

16. Go microservice toolkits plugins
● Broker: PubSub messaging; NATS, NSQ, RabbitMQ, Kafka
● Client/Server: RPC Clients; gRPC, HTTP
● Codec: Message Encoding; BSON, Mercury
● Redistry: Service Discovery; Etcd, Gossip, NATS
● Selector: Load balancing; Label, Cache, Static
● Transport: Bidirectional Streaming; NATS, RabbitMQ
● Wrappers: Middleware; Circuit Breakers, Rate Limiting,
Tracing, Monitoring
https://github.com/micro/go-micro#features

17. Difference

18. Handler at monolith
func main() {
srv := http.Server{Addr: ":8080", Handler: homeHandler}
srv.ListenAndServe()
}
func homeHandler(w http.ResponseWriter, r *http.Request) {
l := hlog.FromRequest(r)
products := ListProducts()
// …
}

19. Handler at monolith
func main() {
srv :=grpc.NewServer(grpc.StatsHandler(&ocgrpc.ServerHandler{}))
svc := &productCatalog{}
pb.RegisterProductCatalogServiceServer(srv, svc)
srv.Serve(l)
}
func (p *productCatalog) GetProduct(ctx context.Context, req
*pb.GetProductRequest) (*pb.Product, error) {

20. Questions?

21. Links
● https://medium.com/seek-blog/microservices-in-go-2fc1570f6800
● https://speakerdeck.com/fedir/building-a-go-microservice-from-0-to-hero
● https://speakerdeck.com/fedir/comparison-of-10-go-web-frameworks
● https://intelligentbee.com/2017/08/14/golang-guide-list-top-golang-frameworks
-ides-tools/

22. Thank you!
Ivan Kutuzov, SoftServe, #GolangUA, @arbrix, ikut@softserveinc.com