Go_GraphQL_in_LINE_SPOT.pdf

Denny Tsai (LINE Taiwan)

Golang Taipei Gathering #40
https://www.meetup.com/golang-taipei-meetup/events/260166791/

1. Go GraphQL in LINE SPOT Golang Taipei Gathering #40
2. Hello, I'm Denny. I work at LINE .
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!