So you Want to Distribute your GraphQL Schema?

Transcript

1. How people build software ! " So you Want to Distribute your GraphQL Schema? @__xuorig__ GraphQL Day Feb. 28th, Toronto
2. How people build software ! Marc-André Giroux @__xuorig__ Montreal, Canada 2 !
3. How people build software " Distributed GraphQL?
4. How people build software " GraphQL
 API query { allPlanets { edges { node { population } } } }
5. How people build software " • Independent development • Independent scalability • Availability • Strong Boundaries • A ton of other good reasons
6. How people build software " Schema 1 query { allPlanets { edges { node { population } } } } Schema 2 Schema 3 Schema n
7. How people build software " Lots of solutions in the past few years...
8. How people build software " Schema Stitching ✨
9. How people build software " ✨ Schema Federation
10. How people build software " Schema Modules ✨
11. How people build software " ✨ Schema Composition
12. How people build software " Namespaces ✨
13. How people build software " ✨ GraphQL Gateway
14. How people build software " Apollo's "Principled GraphQL"
15. How people build software " 1. One Graph (One exposed schema) 2. Federated Implementation (Distributed schema)
16. How people build software " Is this the only way going forward?
17. How people build software " Maybe ¯\_(ツ)_/¯
18. How people build software " But first... a bit of history. Why are we here today?
19. How people build software " Endpoint Based APIs
20. How people build software " • Very well optimized for one use case • Easily cacheable • Provide links to related resources (REST)
21. How people build software " Very optimized for one use case
22. How people build software " API Web Browsers Mobile Servers Analytics Gaming Consoles Your fridge Internal Services
23. How people build software " Each client usually has different data requirements and even slightly different use cases!
24. How people build software " GET /planets GET /planets_for_fridge GET /planets?version=playstation GET /planets?partial=minimal GET /planets?fields=name,population GET /planets?fields=reinventaquerylanguage Accept Header ...
25. How people build software " GraphQL is not the first time we try to solve this problem!
26. How people build software " ~6 years ago @ Netflix
27. How people build software " https://medium.com/netflix-techblog/embracing-the-differences-inside-the-netflix-api-redesign
28. How people build software " ~6 years ago @ SoundCloud
29. How people build software " http://philcalcado.com/2015/09/18/the_back_end_for_front_end_pattern_bff.html
30. How people build software " What was going on at Facebook back then?
31. How people build software "
32. How people build software " GraphQL is kind of a BFF!
33. How people build software " GraphQL is kind of an client-based adapter engine!
34. How people build software " Let's talk distributed schemas!
35. How people build software " Schema Stitching
36. How people build software " type Query { films: [Film!]! } type Film { name: String! } type Query { character(id: ID!): Character } type Character { name: String! } FILM SERVICE CHARACTER SERVICE
37. How people build software " type Query { films: [Film!]! character(id: ID!): Character } type Film { name: String! } type Character { name: String! } GATEWAY
38. How people build software " type Query { films: [Film!]! } type Film { name: String! characters: [Character!]! } type Query { character(id: ID!): Character } type Character { name: String! films: [Film!]! } FILM SERVICE CHARACTER SERVICE
39. How people build software " type Query { films: [Film!]! } type Film { name: String! characters: [Character!]! } type Query { character(id: ID!): Character } type Character { name: String! films: [Film!]! } FILM SERVICE CHARACTER SERVICE ? ?
40. How people build software " Two Options
41. How people build software " 1. ID References
42. How people build software " type Query { films: [Film!]! } type Film { name: String! characters: [Character!]! } type Query { character(id: ID!): Character } type Character { name: String! films: [Film!]! } FILM SERVICE CHARACTER SERVICE ? ?
43. How people build software " type Query { films: [Film!]! filmsById(ids: [ID!]!: [Film!]! } type Film { name: String! characterIDs: [ID!]! } type Query { characters(ids: [ID!]): [Character!]! } type Character { name: String! filmIDs: [ID!]! } FILM SERVICE CHARACTER SERVICE
44. How people build software " • One of GraphQL's great feature is how we can expand relationships within a single query, we've lost that ability because every query requires `ids` to have been fetched before. • To avoid many round trips, schemas that use this approach will try to load as many things as possible using the ID of a certain resource. • Our schema design is affected by the fact our schema is separated in multiple services. Ideally we'd like our clients not be affected by the technical decision of using a distributed architecture.
45. How people build software " 2. Relations at merge time
46. How people build software " type Query { films: [Film!]! } type Film { name: String! characters: [Character!]! } type Query { character(id: ID!): Character } type Character { name: String! films: [Film!]! } FILM SERVICE CHARACTER SERVICE ? ?
47. How people build software " type Query { films: [Film!]! } type Film { name: String! } type Query { character(id: ID!): Character } type Character { name: String! } FILM SERVICE CHARACTER SERVICE
48. How people build software " extend Film { characters: [Character!]! } extend Character { films: [Film!]! } LINKS
49. How people build software " gateway = merge(merge(films, characters), links)
50. How people build software " type Query { films: [Film!]! character(id: ID!): Character } type Film { name: String! } type Character { name: String! } extend Film { characters: [Character!]! } extend Character { films: [Film!]! }
51. How people build software " Gateway (Stitched Schema, Links) Film Service & Schema Character Service & Schema
52. How people build software " Did we actually decentralize?
53. How people build software " Gateway (Stitched Schema, Links) Film Service & Schema Character Service & Schema Adding new functionality Add a new type to the character schema Add a link to "plug in" the new feature with the rest of the schema
54. How people build software " • Schema modifications now often require a two step process (Add new functionality to the right schema, extend at gateway to allow for relationships) • We end up with something still quite centralized because of where the relationships are formed and the final schema is built • It's not very clear where new schema use cases go. We risk that a lot of domain logic will leak into the gateway, making our GraphQL gateway a monolithic API, the thing we wanted to avoid in the first place using this solution.
55. How people build software "
56. How people build software " What should an API Gateway even do? What it should it not do?
57. How people build software " The Goal: Decouple clients from the services involved in consumed use cases
58. How people build software " Avoid: Business logic leaking into the gateway itself
59. How people build software " Avoid: Single Point of Failure
60. How people build software " "We remain concerned about business logic and process orchestration implemented in middleware, especially where it requires expert skills and tooling while creating single points of scaling and control. Vendors in the highly competitive API gateway market are continuing this trend by adding features through which they attempt to differentiate their products. This results in OVERAMBITIOUS API GATEWAY products whose functionality — on top of what is essentially a reverse proxy — encourages designs that continue to be difficult to test and deploy." HTTPS://WWW.THOUGHTWORKS.COM/RADAR/PLATFORMS/OVERAMBITIOUS-API-GATEWAYS
61. How people build software " What about schema composition/federation?
62. How people build software " type Query { films: [Film!]! } type Film { name: String! } extend Character { films: [Film!]! } type Query { character(id: ID!): Character } type Character { name: String! } extend Film { characters: [Character!]! } FILM SERVICE CHARACTER SERVICE
63. How people build software " • Schema Stithing but without the "links" • Choreography vs Orchestration • The "Gateway" does almost nothing in theory
64. How people build software " Type Dependencies
65. How people build software " Testing / Development
66. How people build software " Who's in charge of the "query plans"?
67. How people build software " Tradeoff between development & operational complexity
68. How people build software " I worry about splitting up schemas too early
69. How people build software " Never forget that we're trying to enable use cases, and don't actually care about the services involved
70. How people build software " Splitting schemas per service may be leading us to designing a schema that maps too much to our internal view of things rather than focusing on use cases
71. How people build software " Takeaways
72. How people build software " GraphQL seems like a real great fit to expose an API and decouple clients from the services that enable use cases
73. How people build software " But it's not clear to me we need to split up schemas across the network.
74. How people build software " Use GraphQL as your special "Backend for Frontend"
75. How people build software " Make it as thin as possible
76. How people build software " Ask yourself if the GraphQL API itself needs to be split up
77. How people build software " Chances are you might not need to yet
78. How people build software " If it really does... consider splitting in larger "use case" chunks versus using a lot of small modules
79. How people build software " Keep an eye out for awesome solutions that will be coming up. But... always remember what our initials goals were!
80. How people build software " Thank you! @__xuorig__