This document discusses Geode GraphQL Extension (G2QL), which allows a Geode cache to be accessed via GraphQL queries and mutations. G2QL introspects a Geode cache configuration and generates a corresponding GraphQL schema. It converts GraphQL queries and mutations to Geode region operations and OQL, eliminating the need to write resolvers. G2QL addresses issues like schema duplication, boilerplate code, and inefficient data access through features like schema generation, automatic conversion of queries to Geode operations, and batching of queries. The document provides an example of G2QL in action and discusses next steps for the project.

1. © Copyright 2017 Pivotal Software, Inc. All rights Reserved. Version 1.0
Sai Boorlagadda
October 17, 2018
Geode GraphQL Extension
(G2QL)

2. Agenda
● GraphQL Introduction
● Geode + GraphQL = G2QL
● Demo
● Next Steps

3. GraphQL Introduction
REST vs GraphQL

4. What’s GraphQL?
● new API standard by Facebook
● query language for APIs
● declarative way of fetching &
updating data

5. Strong Community
> 75 companies using GraphQL
https://graphql.org/users/

6. Example: Blogging App

7. Example: Blogging App

8. Example: Blogging App

9. Example: Blogging App using REST

13. Overfetching and Underfetching

14. Product Centric APIs
backend APIs are storage-centric
frontend APIs are product-centric

15. GraphQL = Composition + Projections
Example: Blogging App using GraphQL

18. Core Concepts
Queries & Mutations

19. Queries
... only read data
query MessageQuery {
Message(id: “1”) {
text
sentBy {
name
}
}
}

20. Queries
... only read data
query MessageQuery {
Message(id: “1”) {
text
sentBy {
name
}
}
}
Operation Type
3 Operation Types:
- query (default)
- mutation
- subscription

21. Queries
... only read data
query MessageQuery {
Message(id: “1”) {
text
sentBy {
name
}
}
}
Operation Name

22. Queries
... only read data
query MessageQuery {
Message(id: “1”) {
text
sentBy {
name
}
}
}
Fields

23. Queries
... only read data
query MessageQuery {
Message(id: “1”) {
text
sentBy {
name
}
}
}
Root Field

24. Queries
... only read data
query MessageQuery {
Message(id: “1”) {
text
sentBy {
name
}
}
}
Selection Set

25. Queries
query MessageQuery {
Message(id: “1”) {
text
sentBy {
name
}
}
}
... only read data
{
“data”: {
“Message”: {
“text”: “Hello!”,
“sentBy”: {
“name”: “Bob”
}
}
}
}

26. Queries
query MessageQuery {
Message(id: “1”) {
text
sentBy {
name
}
}
}
... only read data
{
“data”: {
“Message”: {
“text”: “Hello!”,
“sentBy”: {
“name”: “Bob”
}
}
}
}

27. Queries
query MessageQuery {
Message(id: “1”) {
text
sentBy {
name
}
}
}
... only read data
{
“data”: {
“Message”: {
“text”: “Hello!”,
“sentBy”: {
“name”: “Bob”
}
}
}
}

28. Mutations
mutation CreateMessage {
createMessage(text:“Hi”) {
id
}
}
... write and read data
{
“data”: {
“createMessage”: {
“id”: “3”
}
}
}

29. Mutations
mutation CreateMessage {
createMessage(text:“Hi”) {
id
}
}
... write and read data
{
“data”: {
“createMessage”: {
“id”: “3”
}
}
}

30. Mutations
mutation CreateMessage {
createMessage(text:“Hi”) {
id
}
}
... write and read data
{
“data”: {
“createMessage”: {
“id”: “3”
}
}
}

31. Mutations
mutation CreateMessage {
createMessage(text:“Hi”) {
id
}
}
... write and read data
{
“data”: {
“createMessage”: {
“id”: “3”
}
}
}

32. Subscriptions
● event-based real-time updates
● clients subscribe to specific events
● usually implemented with websockets

33. GraphQL Server
Schema & Resolvers

34. GraphQL Server Components
● GraphQL Schema Definition
● Resolver Functions
● GraphQL execution layer
● Network layer

35. GraphQL Server Components
● GraphQL Schema Definition
● Resolver Functions
● GraphQL execution layer
● Network layer } graphql libraries

36. GraphQL Server Components
● GraphQL Schema Definition
● Resolver Functions
● GraphQL execution layer
● Network layer
} Developer
Responsibility

37. GraphQL Schema

38. GraphQL Schema
● Strongly typed & written in Schema
Definition Language(SDL)
● defines API capabilities ( = contract for
client-server communication)
● root types: Query, Mutation, Subscription

39. Example: CRUD for user type
type User {
id: String!
name: String!
}
type Query {
user (id: String): User,
users (id: [String]): [User]
}
type Mutation {
createUser (key: String!, user: User!): User,
updateUser (key: String!, user: User!): User,
deleteUser (key: String!): User
}
query {
user (id: “1“) {
name
}
}
{
“user”: {
“name”: “Bob”
}
}
1.Schema 2.Query 3.Response

40. GraphQL Resolvers

41. GraphQL Resolvers
@Component
public class UserDataFetcher implements DataFetcher<User> {
@Autowired
private final UserDao userDao;
@Override
public User get(DataFetchingEnvironment env) {
String userId = env.getArgument(“userId”);
return userDao.find(userId);
}
}

42. Common Problems

43. ● Schema Duplication
● Boilerplate Overdose
● Client/Server Data Mismatch
● Superfluous Database Calls
first impressions

44. Schema Duplication
Solution: GraphQL Schema Generation
GraphQL Schema Database Schema

45. Boilerplate Overdose
● Define GraphQL Schema
● Write Resolvers for CRUD
Solution: Convert queries and mutation to Geode Operations and OQL

46. Client/Server data mismatch
Solution: Translate GraphQL to OQL
Post:
{
“id”: “1”,
“title”: “G2QL”,
. . .
. . .
“user”: {
“id”: “1”,
“name: “Sai”,
. . .
. . .
}
}
id userid title contents
1 1 G2QL G2QL is a ...
/Post

47. n+1 Database Calls

48. Problem: Schema Duplication
Solution: GraphQL Schema Generation
Problem: Boilerplate Overdose
Solution: Auto convert queries and mutation
to Geode Operations and OQL
Problem: Client/Server data mismatch
Solution: Convert GraphQL to OQL
Problem: Superfluous Database Calls
Solution: Batching & Caching
G2QL is the answer

49. Geode + GraphQL = G2QL

50. Geode GraphQL Extension
● Turns your cache into GraphQL API server
● Introspects and defines GraphQL schema
- types, queries, mutations
● Converts queries & mutations to Region
Operations and OQL
- no need to write resolvers

51. G2QL introspects your cache
type Customer {
fields: - from ValueConstraint
}
type Query {
customer(key: String): Customer,
customer(firstName: String): Customer
}
type Mutation {
createCustomer(key: String!, customer: customer!): Customer,
updateCustomer(key: String!, customer: Customer!): Customer,
deleteCustomer(key: String!): Customer
}
Regions
Customer<String, Customer>
Order<String, Order>
Indexes
create index --name=FirstNameIdx
--expression=firstName --
region=/Customer
Cache Configuration GraphQL Schema
Value Constraints == Types

52. G2QL introspects your cache
type Customer {
fields: - from ValueConstraint
}
type Query {
customer(key: String): Customer,
customer(firstName: String): Customer
}
type Mutation {
createCustomer(key: String!, customer: customer!): Customer,
updateCustomer(key: String!, customer: Customer!): Customer,
deleteCustomer(key: String!): Customer
}
Regions
Customer<String, Customer>
Order<String, Order>
Indexes
create index --name=FirstNameIdx
--expression=firstName --
region=/Customer
Cache Configuration GraphQL Schema
Queries with Key & Indexes

53. G2QL introspects your cache
type Customer {
fields: - from ValueConstraint
}
type Query {
customer(key: String): Customer,
customer(firstName: String): Customer
}
type Mutation {
createCustomer(key: String!, customer: customer!): Customer,
updateCustomer(key: String!, customer: Customer!): Customer,
deleteCustomer(key: String!): Customer
}
Regions
Customer<String, Customer>
Order<String, Order>
Indexes
create index --name=FirstNameIdx
--expression=firstName --
region=/Customer
Cache Configuration GraphQL Schema
Mutations with Region operations

54. G2QL in Action

55. @GeodeGraphQLDescription
@GeodeGraphqDescription(“A student is a Student”)
Class Student{
String id;
String name;
}

56. @GeodeGraphQLIgnore
@GeodeGraphqlIgnore
Class Student{
String id;
String name;
}

57. @GeodeGraphQLConnection
Class Person{
String id;
String name;
@GeodeGraphqlConnection(region=”/person”)
List<String> friends; //store keys to person objects
}

58. G2QL In Action

59. GraphQL clients
There are close to 100 libraries in >20 languages
https://github.com/chentsulin/awesome-graphql

60. Next Steps…
● Non-scalar keys
● Introspect PDX types
● Introspect Lucene indexes
● Introspect Functions
● Cache listeners
● Security
● GraphQL subscription
● GraphQL schema -> cache configuration

61. Questions?

62. References
● G2QL - https://github.com/sboorlagadda/g2ql
● GraphQL - https://graphql.org/
● Apollo GraphQL - https://www.apollographql.com/
● graphql-java - https://github.com/graphql-java/
○ Provides query parser, type system, schema parser, hooks to resolvers

63. Transforming How The World Builds Software
© Copyright 2017 Pivotal Software, Inc. All rights Reserved.