Graphql In Golang

1. Why we moving API from REST to Graphql?
2. What is Graphql?
3. Graphql in Golang (Why we choose Golang)
4. How to testing Graphql in Golang
5. Deploy Graphql application

Transcript

1. GRAPHQL IN GO
   MODERNWEB 2018
   

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2. ABOUT ME
   Open source contributor
   1. Gitea
   2. Drone
   3. Gin
   appleboy @ GitHub
   appleboy @ twitter
   appleboy @ slideshare
   appleboy46 @ facebook
   2
   

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3. AGENDA
   ▸ Why we moving API from REST to Graphql?
   ▸ What is Graphql?
   ▸ Graphql in Golang (Why we choose Golang)
   ▸ How to testing Graphql in Golang
   ▸ Deploy Graphql application
   

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4. MOVING REST TO GRAPHQL
   icon from https://bit.ly/2LhOpZA
   

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5. 1. LARGE REQUEST IN SINGLE PAGE
   https://bit.ly/2NpS4Fu
   

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6. 1. LARGE REQUEST IN SINGLE PAGE
   

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7. CUSTOM FIELDS
   /api/scene/1?field=name,description,created_at
   

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8. CUSTOM ENDPOINT
   /api/scene/1/mobile?field=name,description
   /api/scene/1/web?field=name,description
   

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9. DOCUMENTATION?
   HOW TO GENERATE DOCUMENT AUTOMATICALLY?
   API DOC
   Swagger
   

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10. UPDATE API
    GENERATE DOC
    BACKEND
    FRONTEND MOBILE
    TESTING
    

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11. /**
    * @api {get} /scene/:id Request Scene information
    * @apiName GetScene
    * @apiGroup Scene
    *
    * @apiParam {Number} id Scenes unique ID.
    *
    * @apiSuccess {String} title Title of the Scene.
    * @apiSuccess {String} desc Description of the Scene.
    */
    

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12. GRAPHQL
    

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13. WHAT IS GRAPHQL?
    IT IS A QUERY LANGUAGE
    

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14. {
    myScene {
    name
    description
    }
    }
    LEXED
    PARSED
    VALIDATED
    EXECUTED
    

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15. {
    scene(id: 1) {
    name
    description
    }
    }
    LEXED
    PARSED
    VALIDATED
    EXECUTED
    

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16. {
    scene(id: 1) {
    name
    description
    items(type: DEVICE) {
    id
    name
    url
    }
    }
    }
    Graphql Request
    

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17. {
    "scene": {
    "name": "foo",
    "description": “bar",
    "items": [{
    "id": 1,
    "name": "test_1",
    "url": "http://foo.com"
    }, {
    "id": 2,
    "name": "test_2",
    "url": "http://bar.com"
    }]
    }
    }
    JSON Response
    

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18. /api/scene/1
    /api/scene/1/item
    /api/scene/1/all
    

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19. TYPE SYSTEM
    GRAPHQL LANGUAGE
    

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20. {
    myScene {
    name
    description
    }
    }
    

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21. {
    scene(id: 1) {
    name
    description
    items(type: DEVICE) {
    id
    name
    url
    }
    }
    }
    

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22. type QueryRoot {
    myScene: Scene
    scene(id: ID!): Scene
    }
    

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23. {
    scene(id: 1) {
    name
    description
    items(type: DEVICE) {
    id
    name
    url
    }
    }
    }
    Graphql Request
    

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24. type Scene {
    name: String!
    description: String
    items(type: ItemEnum): [Item]
    }
    enum ItemEnum {
    DEVICE,
    TEST_DEVICE,
    URL
    }
    

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25. {
    scene(id: 1) {
    name
    description
    items(type: DEVICE) {
    id
    name
    url
    }
    }
    }
    Graphql Request
    

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26. type Item {
    id: ID!
    name: String!
    url: String
    }
    

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27. INTROSPECTION
    GRAPHQL LANGUAGE
    

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28. {
    __schema {
    queryType {
    name
    }
    }
    }
    

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29. {
    "data": {
    "__schema": {
    "queryType": {
    "name": "Query"
    }
    }
    }
    }
    

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30. WHY NEED THE INTROSPECTION
    ▸code generation
    ▸auto documentation
    ▸static validation
    ▸IDE Integration
    

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31. https://github.com/prismagraphql/graphql-playground
    

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32. https://www.prisma.io/blog/introducing-graphql-playground-f1e0a018f05d/
    

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33. RESOLVING FIELDS
    GRAPHQL LANGUAGE
    

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34. type Item {
    id: ID
    type: sceneEnum
    name: String
    }
    

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35. "id": &graphql.Field{
    Type: graphql.Int,
    },
    INT FLOAT STRING BOOLEAN ID
    

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36. type Item {
    id: ID
    type: sceneEnum
    name: String
    }
    

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37. "TEST_DEVICE": &graphql.EnumValueConfig{
    Value: int(model.TypeTestDevice),
    Description: "test device.",
    },
    "DEVICE": &graphql.EnumValueConfig{
    Value: int(model.TypeDevice),
    Description: "device.",
    },
    "URL": &graphql.EnumValueConfig{
    Value: int(model.TypeURL),
    Description: "url.",
    },
    

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38. "name": &graphql.Field{
    Type: graphql.String,
    Resolve: func(p graphql.ResolveParams) (interface{}, error) {
    o, _ := p.Source.(*model.Scene)
    return "Hello, " + o.Name, nil
    },
    },
    Return Custom Value
    

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39. MUTATION
    GRAPHQL LANGUAGE
    

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40. mutation {
    createScene(
    title: "foo",
    description: "bar"
    ) {
    id
    title
    description
    url
    }
    }
    

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41. // Schema is the GraphQL schema served by the server.
    var Schema, _ = graphql.NewSchema(graphql.SchemaConfig{
    Query: rootQuery,
    Mutation: rootMutation,
    Types: types,
    })
    Query and Mutation
    

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42. SINGLE ENDPOINT
    POST /graphql
    

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43. GRAPHQL IN GOLANG
    WHY WE CHOOSE GOLANG?
    

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44. WHY WE CHOOSE GOLANG?
    ▸Compiles Into Single Binary
    ▸Static Type System
    ▸Performance
    ▸Easy to Deploy
    ▸Learning Curve
    

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45. BENCHMARK OF GRAPHQL FRAMEWORK IN GOLANG
    ▸graphql-go/graphql
    ▸playlyfe/go-graphql
    ▸graph-gophers/graphql-go
    ▸samsarahq/thunder
    

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46. https://github.com/appleboy/golang-graphql-benchmark
    $ go test -v -bench=. -benchmem
    

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47. VEKTAH/GQLGEN
    GO GENERATE BASED GRAPHQL SERVER
    LIBRARY
    https://github.com/vektah/gqlgen
    https://youtu.be/3dpqYMqyiOg
    

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49. API SERVER
    API SERVER
    GRAPHQL SERVER
    GRAPHQL GATEWAY
    

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50. GRAPHQL IN GOLANG
    PACKAGE IN GOLANG
    

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51. FRAMEWORK IN GO
    

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52. func Handler() gin.HandlerFunc {
    h := handler.New(&handler.Config{
    Schema: &schema.Schema,
    Pretty: true,
    })
    return func(c *gin.Context) {
    h.ServeHTTP(c.Writer, c.Request)
    }
    }
    graphql schema
    

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53. JWT TOKEN
    SERVER
    GRAPHQL
    SERVER
    

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54. func Check() gin.HandlerFunc {
    return func(c *gin.Context) {
    token := c.GetHeader("Authorization")
    user, err := authUser(token)
    if token != "" && err != nil {
    logrus.Errorf("authUser error: %s", err.Error())
    }
    if user != nil && user.Email != "" {
    c.Set("email", user.Email)
    c.Set("user_id", user.UserID)
    }
    ctx := context.WithValue(
    c.Request.Context(),
    config.ContextKeyUser,
    user,
    )
    c.Request = c.Request.WithContext(ctx)
    }
    }
    store user data
    

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55. var Schema, _ = graphql.NewSchema(graphql.SchemaConfig{
    Query: rootQuery,
    Mutation: rootMutation,
    })
    var rootMutation = graphql.NewObject(
    graphql.ObjectConfig{
    Name: "RootMutation",
    Description: "Root Mutation",
    Fields: graphql.Fields{
    "updateUser": &updateUser,
    "createScene": &createScene,
    "updateScene": &updateScene,
    "deleteScene": &deleteScene,
    },
    })
    var rootQuery = graphql.NewObject(
    graphql.ObjectConfig{
    Name: "RootQuery",
    Description: "Root Query",
    Fields: graphql.Fields{
    "queryUser": &queryUser,
    "searchUser": &searchUser,
    "queryScene": &queryScene,
    },
    })
    query
    mutation
    

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56. GRAPHQL ERROR
    BETTER ERROR HANDLING
    

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57. {
    "data": {
    "post": null
    },
    "errors": [
    {
    "message": "Internal Error: 404 not found",
    "locations": [
    {
    "line": 2,
    "column": 3
    }
    ],
    "path": [
    "post"
    ]
    }
    ]
    }
    single message
    error location
    

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58. func (g FormattedError) MarshalJSON() ([]byte, error)
    {
    m := map[string]interface{}{}
    for k, v := range g.Extensions {
    m[k] = v
    }
    m["message"] = g.Message
    m["locations"] = g.Locations
    return json.Marshal(m)
    }
    Marshal JSON
    custom key value
    

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59. func FormatError(err error, arg ...interface{}) gqlerrors.FormattedError
    {
    switch err := err.(type) {
    case gqlerrors.FormattedError:
    return err
    case *Error:
    return gqlerrors.FormattedError{
    Message: fmt.Sprintf(err.Error(), arg...),
    Extensions: gqlerrors.ErrorExtensions{
    "code": err.Type.Code(),
    "type": err.Type,
    },
    }
    } custom error
    original error
    

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60. GRAPHQL N+1
    DATA LOADER
    

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61. 1. LARGE REQUEST IN SINGLE PAGE
    

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62. {
    myScene(id: 1) {
    name
    description
    role {
    id
    user {
    email
    }
    model
    }
    }
    }
    

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63. ORM IN GOLANG
    GOORM VS XORM
    

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64. type Scene struct {
    ID int64 `xorm:"pk autoincr" json:"id"`
    Image string `json:"image,omitempty"`
    CreatedAt time.Time `json:"createdAt,omitempty"`
    UpdatedAt time.Time `json:"updatedAt,omitempty"`
    DeletedAt time.Time `xorm:"deleted"`
    // reference
    Items []*SceneItem `xorm:"-" json:"items,omitempty"`
    User *User `xorm:"-" json:"user,omitempty"`
    Role *SceneAccess `xorm:"-" json:"role,omitempty"`
    }
    Data Model
    user role permission
    

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65. "user": &graphql.Field{
    Type: userType,
    Resolve: func(p graphql.ResolveParams) (interface{}, error) {
    o, ok := p.Source.(*model.Shorten)
    if !ok {
    return nil, errMissingSource
    }
    if o.User != nil {
    return o.User, nil
    }
    return getUserFromLoader(p.Context, o.UserID)
    },
    },
    exist in model?
    fetch from loader
    

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66. GET DATA FROM DATABASE IF NOT EXIST
    func userBatch(ctx context.Context, keys dataloader.Keys) []*dataloader.Result {
    var results []*dataloader.Result
    id, _ := helper.GetCacheID(keys[0].String())
    user, err := model.GetUserByID(id.(int64))
    results = append(results, &dataloader.Result{
    Data: user,
    Error: err,
    })
    return results
    }
    fetch from DB
    

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67. GRAPHQL DATALOADER
    ONLY SUPPORT MEMORY, LRU OR TTL
    CACHE
    

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68. INTEGRATE WITH REDIS SERVICE
    GRAPHQL DATALOADER
    

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69. func batchFunc(_ context.Context, keys dataloader.Keys) []*dataloader.Result
    {
    results := make([]*dataloader.Result, len(keys))
    // get what you can from redis
    values, _ := redisClient.MGet(...keys.Keys()).Result()
    // make a list of everything that was not found in redis
    var cacheMisses map[int]string
    for i := range keys {
    if values[i] == redis.Nil {
    cacheMisses[i] = keys[i].String()
    } else {
    results[i] = &dataloader.Result{values[i], nil}
    }
    }
    // get the missing items from more expensive location (like DB)
    for idx, key := range cacheMisses {
    value, err := db.GetValues(key) // Pseudo code!
    redisClient.Set(key, value)
    results[idx] = &dataloader.Result{value, err}
    }
    return results
    }
    miss from redis
    fetch from DB
    

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70. HOW TO TEST GRAPHQL SCHEMA?
    GRAPHQL TESTING
    

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71. https://code.likeagirl.io/the-7-steps-to-a-complete-code-review-abdfd39e75f1
    

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72. RAILS-LIKE TEST FIXTURES FOR GO
    GO TEST FIXTURES
    https://github.com/go-testfixtures/testfixtures
    

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73. -
    id: 1
    email: foo@gmail.com
    full_name: foo
    avatar: http://foo.com
    avatar_email: foo@gmail.com
    -
    id: 2
    email: bar@gmail.com
    full_name: bar
    avatar: http://bar.com
    avatar_email: bar@gmail.com
    real data in DB
    

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74. test := T{
    Query: `
    query QueryShortenURL (
    $slug: String!
    ) {
    QueryShortenURL(slug: $slug) {
    url
    }
    }
    `,
    Schema: Schema,
    Expected: &graphql.Result{
    Data: map[string]interface{}{
    "QueryShortenURL": map[string]interface{}{
    "url": "http://example.com",
    },
    },
    },
    }
    graphql query
    expect data
    

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75. params := graphql.Params{
    Schema: test.Schema,
    RequestString: test.Query,
    Context: ctx,
    VariableValues: map[string]interface{}{
    "slug": "abcdef",
    },
    }
    testGraphql(test, params, t)
    ctx := newContextWithUser(context.TODO(), user)
    user data in context
    graphql variable
    

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76. all pass
    testing in sqlite
    

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77. GRAPHQL DEPLOYMENT
    HOW TO DEPLOY GOLANG APP?
    

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78. GO-GGZ/GGZ
    AN URL SHORTENER SERVICE WRITTEN IN GO
    https://github.com/go-ggz/ggz
    

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79. Thanks
    

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