Go Backends for frontends with GraphQL and gRPC

Transcript

1. Go Backends for Frontends with and @__timakin__
2. Seiji Takahashi Software Engineer Gunosy Inc. Tokyo, Japan.
3. BFF
4. Backends For Frontends
5. BFF (Web) BFF (Native) User Micro Service Article Micro Service Payment Micro Service Access Controled Web Browser iOS/Android
6. Pros of BFF • Each microservices can focus on only their own responsibility. • Customize networking protocol for each clients. • Flexibly change the response fields.
7. BFF Use-cases 1. API Aggregation 2. Session Management 3. SSR 4. File Upload 5. WebSocket
8. BFF Use-cases 1. API Aggregation BFF User Micro Service Article Micro Service Comment Micro Service Client Concat every JSON Object from internal APIs Send requests to several services concurrently Request an article entity
9. BFF Use-cases 2. Session Management BFF User Micro Service Article Micro Service Comment Micro Service Client Send requests with token Get data from session store Send session_id Session Store
10. Page request BFF Use-cases 3. SSR BFF User Micro Service Article Micro Service Comment Micro Service Client Concat every JSON and pass them to HTML renderer Data fetching
11. Chunked file upload BFF Use-cases 4. File Upload BFF External File Storage Internal API Client Send a request with filePath Store file
12. Connect with WS BFF Use-cases 5. WebSocket/Polling BFF Message Queue Internal API Client Pub/Sub
13. Micro Service Today’s CaseStudy BFF Micro Service Micro Service Web Client
14. • When they talk about BFF… ◦ JavaScript(Node) is popular in most of the cases. ◦ Because it eases the communication between frontend & backend engineers. BFF in Go
15. • Why Go? ◦ If you are a backend engineer, Go BFF will be a good choice from the aspect of performance. ◦ With goroutine, Go would handle the concurrent internal accesses rapidly. ▪ If you threw away REST and changed into RPC-call, you must send request multiple servers everytime. ▪ This means internal latency is critical for UX. ◦ Awesome packages for both of GraphQL and gRPC exist in Go community. BFF in Go
16. GraphQL
17. • GraphQL is a simple query language for API which has the type system. • Instead of JSON request in like REST API or JSON-RPC, you will send `query` to GraphQL server. • Implementation in JavaScript is the most active. GraphQL introduction
18. Client
19. GraphQL vs gRPC • Generally, GraphQL is hotter than gRPC. • In a lot of countries GraphQL wins. • However, in East Asia(especially in China), gRPC has more fans.
20. • Client-side-related words like `apollo`, `react`. • `github` is ranked in the top 10. Related words of each protocols • Server-side languages like `java` , `goland`, `python` and the format `protobuf`.
21. • In-browser playground to explore GraphQL calls. GraphiQL
22. • Packages ◦ graphql-go/graphql ◦ graphql-go/relay ◦ samsarahq/thunder ◦ 99designs/gqlgen GraphQL in Go
23. • Packages ◦ graphql-go/graphql ◦ graphql-go/relay ◦ samsarahq/thunder ◦ 99designs/gqlgen GraphQL in Go
24. • github.com/99designs/gqlgen ◦ Active development ◦ Type-Safe ◦ Schema Driven ◦ Custom middleware appendable GraphQL in Go
25. • github.com/99designs/gqlgen ◦ Active development ◦ Type-Safe ◦ Schema Driven ◦ Custom middleware appendable GraphQL in Go
26. • github.com/99designs/gqlgen-contrib ◦ package of middlewares for performance tracing ▪ apollo-tracing ▪ opencensus • datadog ▪ opentracing ▪ prometheus GraphQL in Go
27. GraphQL in Go • Other packages ◦ Cannot share schema with frontend ◦ Reflection based schema ▪ A negative effect to latency
28. schema.graphql Prepare schemas Instead of auto-generated code, you can use defined structs. gqlgen.yml
29. $ gqlgen Code generate
30. The implementation inside functions are not automatically generated. Write your own code. grpc client
31. When you test GraphQL • Integration test with input & golden files. ◦ Record a real request and response ◦ Mock or temporarily boot internal API ◦ Iterate recorded files and check the equality with the actual responses
32. gRPC
33. • HTTP/2 networking • Protobuf serialization ◦ template code generation • Go is one of the most active languages for gRPC implementation. • Number of Github stars ◦ Go > Java > Node > Swift > PHP > Haskell
34. • github.com/golang/protobuf/proto • github.com/golang/protobuf/protoc-gen-go • google.golang.org/grpc Required packages • github.com/ktr0731/evans • github.com/uber/prototool Optional tools
35. blog.proto Schema
36. uber/prototool strictly checks and formats *.proto Linter
37. Linter Define the rules on prototool.yaml Run commands
38. Code Generation github.com/golang/protobuf/protoc-gen-go
39. Client
40. Client send a request to internal gRPC API
41. Server
42. Server
43. Server Call the logic implemented by yourself e.g. DB access, external API-call
44. After implementation ktr0731/evans helps you to explore your gRPC server locally
45. Conclusion • Go is one of the best candidate language for BFF. • GraphQL + gRPC will empower you with schema-driven-development and low-latency protocol.
46. Thank you for listening