Apidays Paris 2023 - GraphQL Nullability, State of the Union, Martin Bonnin, Apollo GraphQL

Apidays Paris 2023 - Software and APIs for Smart, Sustainable and Sovereign Societies
December 6, 7 & 8, 2023

GraphQL Nullability, State of the Union
Martin Bonnin, Mobile Engineer at Apollo GraphQL

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Transcript

1. GraphQL nullability State of the union apidays 2023
2. Agenda • Problem • Solutions
3. Part I: the problem
5. { "data" { "video": { "id": "42", "title": "GraphQL 101", "uploadDate": "2023-12-03T22:26:46Z" } } }
8. 2017 Nullable types!
9. ❤
10. But… Non-Null String String! Nullable String? String 💪 🤔
11. query GetVideo { video(id: "42") { title description viewCount comments(first: 5) { nodes { author text } } } } Nullable
12. ??Why is everything nullable???? ????? ??
13. https://graphql.org/learn/best-practices/#nullability
15. Error null != Semantic null { "errors": [ { "message": "cannot resolve title", "path": "video.title" } ] "data": { "video": { "id": "42", "title": null } } }
16. Terminology • Error null ◦ Exceptional case ◦ Has an error in the errors array • Semantic null ◦ Business case ◦ No error in the errors array
17. @Composable fun VideoItem(video: Video) { Text(text = video.title!!) }
18. @Composable fun VideoItem(response: Response) { if (response.errors.isNotEmpty()) { Error() } else { Text(text = response.data.video.title!!) } }
19. 2 months later
20. Post mortem • New feature: video upload • During the upload, a video doesn’t have a title yet • This was a backward compatible schema change!
21. @Composable fun VideoItem(response: Response) { if (response.errors.isNotEmpty()) { Error() } else { if (response.data.video.title == null) { Text(text = "This video doesn't have a title yet") } else { Text(text = response.data.video.title) } } }
22. Different shades of error handling
23. There is more…
25. @Composable fun VideoItem(response: Response) { if (response.errors.any { it.path == "video.title" }) { Error() // Can't display a video without a title } else { if (response.data.video.title != null) { Text(text = "This video does not have a title yet") } else { Text(text = response.data.video.title!!) } if (response.errors.any { it.path == "video.viewCount" }) { // Skip viewCount } else { Text(text = "${response.data.video.viewCount!!} + views") } } } Partial data
26. 10 fields ⇨ 1024 possibilities
27. Guessing game • Semantic null? • Error null? • 🤷
28. GraphQL is missing types Your favorite type-safe language GraphQL string → String! string | null → String string | error → String string | null | error → String
29. Part II: solutions
30. Documentation type Video { """ The title of the Video null if the video has just been uploaded """ title: String """ Number of times this video has been watched Never null unless there is an error """ viewCount: Int }
31. Evolving the language
32. Nullability working group 2021 Client Controlled Nullability May 2023 sub working group Sep 2023 GraphQL conf True nullability Asterisk Interrobang Oct 2023 semantic-non-null @strictNullability @catch graphql/nullability-wg
33. Nullability working group 2021 Client Controlled Nullability May 2023 sub working group Sep 2023 GraphQL conf True nullability Asterisk Interrobang Oct 2023 semantic-non-null @strictNullability @catch graphql/nullability-wg
34. Asterisk string → String! string | null → don’t use string | error → String* string | null | error → String graphql/graphql-spec/pull/1048 Never a semantic null
35. Strict nullability string → String! string | null → don’t use string | error → String string | null | error → String? graphql/graphql-wg/discussions/1410 schema @strictNullability { query: Query } Never a semantic null
36. ❤
37. Conclusion • null is not always what it seems! • be aware of the tradeoffs • document nullability • get involved!
38. Thank you! graphql/nullability-wg
39. Empty slide
40. Input nullability string → String! string | null → String string | absent → String string | null | absent → String graphql/graphql-spec/issues/476
41. Semantic non-null string → String! string | null → don’t use string | error → !String string | null | error → String graphql/graphql-spec/pull/1065
42. Interrobang string → String! string | null → don’t use string | error → String!? string | null | error → String graphql/graphql-spec/pull/1046
43. string → String! string | null → don’t use string | error → String @semanticNonNull string | null | error → String @semanticNonNull
44. Problem 2: what default? • Fail the whole query ◦ Easy ◦ Fragile • Handle field errors ◦ Hard ◦ Robust
45. Opting in error handling • Start easy • Add error handling progressively fragment VideoDetails on Video { video { title # opt-in error handling viewCount @catch } } facebook/relay/issues/4416
46. Opting in error handling fragment VideoDetails on Video { video { title # opt-in error handling viewCount @catch } } sealed interface Result<T> { class Success(val value: T): Result class Failure(val error: error): Result } Video( val title: String val viewCount: Result<Int> ) apollographql/apollo-kotlin/pull/5405
47. Client Controlled Nullability graphql/graphql-wg/blob/main/rfcs/ClientControlledNullability.md fragment videoDetails on Video { video { # We need title to display a video title! # It's okay to fail viewCount viewCount? } }
48. string → String string | null → String? string | error → String @throws string | null | error → String? @throws Exceptions graphql/nullability-wg/discussions/39
49. Exceptions string → don’t use string | null → don’t use string | error → String string | null | error → String? graphql/nullability-wg/discussions/39
51. Layouts How do I add a new slide with a preexisting layout? Layout Guidelines To add template to a blankslide, click on layout. Click on any template and start editing.
52. Font & Sizes How do I edit text while keeping the same font style and size? Layout Guidelines Right click “Paste without formatting” Or select your text and click “Clear formatting”
53. Add images How do I add a image container? Layout Guidelines Click on the picture icon to replace image Double Click to resize or adjust image placement Test it out here!
54. Iconography Library 1 Database CMS BFF API Event Queue Web IOS Android IoT AI
55. Iconography Library 2 BFF BFF BFF BFF
56. Illustrations Library 1 Supergraph
57. Illustrations Library 2
58. Illustrations Library 3
59. Illustrations Library 4
60. Typeface Guidelines DM Sans Heading 1: 36 - Bold Heading 2: 24 - Bold
61. Typeface Guidelines Inter Body 1: 12 - Regular - Medium - Bold
62. Background colors Color Guidelines #15252D #FFEADB #CFD7D6 Typeface color Aa Aa Aa Aa #FFFFFF
63. Layouts Examples👇
64. Intro cover
65. October, 2023 The value journey with Apollo GraphOS
66. Exploring what we learned from hundreds of organizations transforming their business and customer experiences with GraphQL Insights on the rise of GraphQL John Doe Engineer Katharina Wagner October 2023 Sunday palace Engineer
67. Exploring what we learned from hundreds of organizations transforming their business and customer experiences with GraphQL Insights on the rise of GraphQL John Doe Engineer Katharina Wagner Engineer October 2023 on Sunday Palace
68. Title Paragraph Eyebrow
69. Title Paragraph Eyebrow
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71. Title Paragraph Eyebrow
73. Slide cover 1
74. A Data Streaming Platform which didn’t make the ecosystem sustainable
75. Slide cover 2
76. “If a monolithic architecture is working for your company, then don't let us be the ones to convince you otherwise. If you are down this microservices road, then Federation is a really great option.” Meeng Chee CEO at Peloton Email or contact
77. APIs fuel growth. They are a critical component of every digital initiative in the modern age. Modernization initiatives Developer velocity Omni-channel Mergers and acquisitions
78. How do the developers that support these initiatives access all of these APIs? Products Images Deals Reviews Inventory Recommend ations
79. Three GraphQL Pillars Option B Option A Option C
80. • Self-service Teams can use them asynchronously. • Paved road A clear, proven path for teams to follow. • Time to value New users get great results quickly. • Coherence Teams can easily find what they need. • Cohesion Features build on each other. • Opinionated A platform cannot be one-size-fits all.
81. A really long long subtitle with at least 3 lines of text. Item title Build variants of your graph for testing, staging, and production environments. Prevent breaking changes Ensure you can safely deliver changes across all clients using schema checks. Communicate cross-functionally Deliver notifications to systems and teams using webhooks. Title
82. Safely ship changes to the graph with tools that integrate with your CI/CD pipeline. Test with ease Build variants of your graph for testing, staging, and production environments. Prevent breaking changes Ensure you can safely deliver changes across all clients using schema checks. Communicate cross-functionally Deliver notifications to systems and teams using webhooks. DELIVER