Go_GraphQL_in_LINE_SPOT.pdf

Transcript

1. Go GraphQL in LINE SPOT Golang Taipei Gathering #40

2. Hello, I'm Denny. I work at LINE .

3. None
4. None

5. 2019 Q3

6. API Gateway with Go & GraphQL for Microservices

7. API Gateway Go GraphQL

8. Client to Monolith

9. Client to Microservices HTTP HTTP HTTP HTTP HTTP HTTP

10. Client to Microservices HTTP HTTP HTTP gRPC Thrift xRPC

11. Client to API Gateway to Microservices backend for frontend

12. Client to API Gateway

13. REST API

14. https://api.github.com/search/repositories?q=language:go&sort=stars&order=desc { "items": [ { "id": 23096959, "node_id": "MDEwOlJlcG9zaXRvcnkyMzA5Njk1OQ==", "name":

    "go", "full_name": "golang/go", "owner": { "login": "golang" }, "url": "https://api.github.com/repos/golang/go", "description": "The Go programming language", "issues_url": "https://api.github.com/repos/golang/go/issues{/number}", "stargazers_count": 56341 } ] }

15. https://api.github.com/repos/golang/go/issues [ { "url": "https://api.github.com/repos/golang/go/issues/31459", "number": 31459, "title": "cmd/link: Apple's

    symbols tool unable to read DWARF data from c-archive go.o", "user": { "login": "tmm1", "avatar_url": "https://avatars2.githubusercontent.com/u/2567?v=4", }, "state": "open" }, { "url": "https://api.github.com/repos/golang/go/issues/31458", "number": 31458, "title": "cmd/go: mod meta tag causes infinite loop in GOPROXY", "user": { "login": "marwan-at-work", "avatar_url": "https://avatars0.githubusercontent.com/u/16294261?v=4", }, "state": "open" } ]

16. Client to API Gateway

17. Multiple Client Types to API Gateway

18. Consumer centric API

19. GraphQL

20. Query language

21. Single endpoint

22. Response shape defined by the client

23. Transport agnostic

24. { repository( owner: "golang" name: "go" ) { name issues(

    first: 2 orderBy: { field: CREATED_AT direction: DESC } ) { totalCount nodes { number title } } } } { "data": { "repository": { "name": "go", "issues": { "totalCount": 30761, "nodes": [ { "number": 31459, "title": "cmd/link: Apple's symbols tool ..." }, { "number": 31458, "title": "cmd/go: mod meta tag causes ..." } ] } } } }

25. { repository( owner: "golang" name: "go" ) { name issues(

    first: 2 orderBy: { field: CREATED_AT direction: DESC } ) { totalCount nodes { number title } } } } { "data": { "repository": { "name": "go", "issues": { "totalCount": 30761, "nodes": [ { "number": 31459, "title": "cmd/link: Apple's symbols tool ..." }, { "number": 31458, "title": "cmd/go: mod meta tag causes ..." } ] } } } }

26. Queries and Mutations

27. GraphQL schema is typed

28. query { repository( owner: String! name: String! ): Repository }

    type Repository { name: String! issues( orderBy: IssueOrder first: Int ): IssueConnection! } type IssueConnection { totalCount: Int! nodes: [Issue] } type Issue { number: Int! title: String! } { repository( owner: "golang" name: "go" ) { name issues( first: 2 orderBy: { field: CREATED_AT direction: DESC } ) { totalCount nodes { number title } } } } type IssueOrder { field: IssueOrderField! direction: OrderDirection! } enum IssueOrderField { CREATED_AT UPDATED_AT COMMENTS } enum OrderDirection { ASC DESC }

29. mutation { createIssue( input: CreateIssueInput! ): CreateIssuePayload } type CreateIssuePayload

    { clientMutationId: String issue: Issue } input CreateIssueInput { repositoryId: ID! title: String! body: String assigneeIds: [ID!] milestoneId: ID labelIds: [ID!] projectIds: [ID!] clientMutationId: String } mutation { createIssue( input: { repositoryId: "..." title: "New issue" body: "This is a new issue" } ) { clientMutationId issue { number title } } }

30. graphql.org

31. Tooling

32. GraphiQL

33. GraphQL Playground

34. Create a GraphQL server with Go

35. graphql-go/graphql graph-gophers/graphql-go 99designs/gqlgen

36. gqlgen

37. Schema first

38. Type safe

39. Less boilerplate

40. Create a schema type Query { posts: [Post] post(id: Int!):

    Post } type Post { id: Int! title: String! body: String! }

41. Initialize with gqlgen ➜ apigateway go run github.com/99designs/gqlgen init Exec

    "go run ./server/server.go" to start GraphQL server ➜ apigateway tree . ├── generated.go ├── go.mod ├── go.sum ├── gqlgen.yml ├── models_gen.go ├── resolver.go ├── schema.graphql └── server └── server.go

42. Resolver Interface type QueryResolver interface { Posts(ctx context.Context) ([]*Post, error)

    Post(ctx context.Context, id int) (*Post, error) }

43. Resolvers type Resolver struct{} func (r *Resolver) Query() QueryResolver {

    return &queryResolver{r} } type queryResolver struct{ *Resolver } func (r *queryResolver) Posts(ctx context.Context) ([]*Post, error) { panic("not implemented") } func (r *queryResolver) Post(ctx context.Context, id int) (*Post, error) { panic("not implemented") }

44. Generated models type Post struct { ID int `json:"id"` Title

    string `json:"title"` Body string `json:"body"` }

45. Configuration schema: - schema.graphql exec: filename: generated.go model: filename: models_gen.go

    resolver: filename: resolver.go type: Resolver models: Post: model: apigateway.Post

46. Generated server const defaultPort = "8080" func main() { port

    := os.Getenv("PORT") if port == "" { port = defaultPort } http.Handle("/", handler.Playground("GraphQL playground", "/query")) http.Handle("/query", handler.GraphQL(apigateway.NewExecutableSchema(...))) log.Printf("connect to http://localhost:%s/ for GraphQL playground", port) log.Fatal(http.ListenAndServe(":"+port, nil)) }

47. Create a GraphQL schema Initialize with gqlgen Implement resolvers Update

    GraphQL schema Generate new code with gqlgen Implement new resolvers

48. Demo

49. Authentication Quotas/Rate limiting Request logging ...

50. Hello, I'm YourName. I work at LINE .

51. Thanks!