GraphQL on Microservices Landscape

GRAPHQL ON MICROSERVICES LANDSCAPE Sergey Ponomarev How to put it
all together

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup 2 @sponomarev @bufo_alvarius Sergey
Ponomarev

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup 3

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup 5 evilmartians.com

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup evilmartians.com/chronicles 6

(MICRO)SERVICES

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup WHY? ‣ Decomposition ‣
Best tools for a task ‣ Scalability ‣ etc. 8

DISTRIBUTED DATA

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup MY AWESOME MONOLITH 10

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup MY AWESOME SERVICES 11

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup INTERNAL COMMUNICATIONS 12

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup MESSAGE BUS 13

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup MESSAGE BUS 14

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup EXTERNAL COMMUNICATIONS 15

THERE ARE MANY OF THEM, AND I AM ALONE

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup NAME THEM ALL ‣
store.api.awesome.store ‣ payments.api.awesome.store ‣ auth.api.awesome.store ‣ chat.api.awesome.store ‣ etc… 17

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup ‣ Separate requests ‣
Different protocols ‣ Hard to manage and refactor 18

ONE ON ONE

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup API GATEWAY 20

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup COMBINE AND CONQUER ‣
api.awesome.store • /products • /orders • /proﬁle • /messages • etc… 21

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup ‣ Simpliﬁed interface ‣
Complexity is hidden ‣ Single protocol ‣ Additional features* 22

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup ‣ One request ‣
No over- and under-fetching problems ‣ Docs out-of-the-box ‣ Frontenders ❤ us 24

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup query { orders {
createdAt product { name price } payment { createdAt } } } 25

# orders service createdAt product { # store service name price } payment { # payments service createdAt } } } 26

# orders service id productId createdAt product { # store service name price } payment { # payments service createdAt } } } 27

SCHEMA STITCHING

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup ORDERS 29 type Query
{ orders: [Order] } type Order { id: Int! productId: Int! createdAt: Date! }

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup PRODUCTS 30 type Query
{ product(id: Int!): Product } type Product { id: Int! name: String! price: Float! }

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup PAYMENTS 31 type Query
{ payment(orderId: Int!): Payment } type Payment { id: Int! orderId: Int! createdAt: Date! }

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup REMOTE SCHEMA 32 const
link = new HttpLink({ uri: 'http: //store.api', fetch }); const schema = await introspectSchema(link); const ordersSchema = makeRemoteExecutableSchema({ schema, link, });

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup EXTENDED SCHEMA 33 extend
type Order { product: Product! payment: Payment! }

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup MERGE SCHEMAS 34 mergeSchemas({
schemas: [ ordersSchema, productsSchema, paymentsSchema, extendedSchema, ], });

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup RESOLVERS 35 Order: {
product: { fragment: ' ... on Order { productId }', resolve(order, args, context, info) { return info.mergeInfo.delegateToSchema({ schema: productSchema, operation: 'query', fieldName: 'product', args: { id: order.productId, }, context, info, }); }, }, },

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup SCHEMA STITCHING ✅ Compose
distributed graph ✅ Grained control over the ﬁnal schema ❌ Requires additional code ❌ Imperative management ❌ Allows bad practices 36

GRAPHQL FEDERATION

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup APOLLO FEDERATION ✅ Compose
distributed graph ✅ Does not require additional code ✅ Declarative management ✅ Stimulates conventions, standards 39

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup TOOLS @apollo/federation @apollo/gateway 40

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup GATEWAY 41 const gateway
= new ApolloGateway({ serviceList: [ { name: 'orders', url: 'http: //store.api' }, { name: 'products', url: 'http: //products.api' }, { name: 'payments', url: 'http: //payments.api' }, ], }); const server = new ApolloServer({ gateway }); server.listen();

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup ORDERS 42 extend type
Query { orders: [Order] } type Order @key(fields: "id") { id: Int! productId: Int! createdAt: Date! }

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup PRODUCTS 43 type Product
@key(fields: "id") { id: Int! name: String! price: Float! } extend type Order @key(fields: "id") { id: Int! @external productId: Int! @external product: Product! @requires(fields: "productId") }

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup PAYMENTS 44 type Payment
{ id: Int! orderId: Int! createdAt: Date! } extend type Order @key(fields: "id") { id: Int! @external payment: Payment! }

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup RESOLVERS: ENTITIES 45 const
resolvers = { Order: { __resolveReference(order, { fetchOrderById }) { return fetchOrderById(order.id); }, }, };

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup RESOLVERS: EXTENSIONS 46 const
resolvers = { Order: { product(order, { fetchProductById }) { return fetchProductById(order.productId); }, }, };

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup QUERY query { orders
{ createdAt product { name price } payment { createdAt } } } 47

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup QUERY PLAN 48 QueryPlan
{ Sequence { Fetch(service: "orders") { { orders { createdAt __typename id productId } } }, ...

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup QUERY PLAN 49 Parallel
{ Flatten(path: "orders.@") { Fetch(service: "products") { ... }, }, Flatten(path: "orders.@") { Fetch(service: "payments") { ... }, }, },

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup QUERY PLAN 50 Fetch(service:
"products") { { ... on Order { __typename id productId } } => { ... on Order { product { name price } } } },

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup QUERY PLAN 51 Fetch(service:
"payments") { { ... on Order { __typename id } } => { ... on Order { payment { createdAt } } } },

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup FEDERATION SPECS 52

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup SCHEMA 53 scalar _Any
scalar _FieldSet # a union of all types that use the @key directive union _Entity type _Service { sdl: String } extend type Query { _entities(representations: [_Any!]!): [_Entity]! _service: _Service! } directive @external on FIELD_DEFINITION directive @requires(fields: _FieldSet!) on FIELD_DEFINITION directive @provides(fields: _FieldSet!) on FIELD_DEFINITION directive @key(fields: _FieldSet!) on OBJECT | INTERFACE directive @extends on OBJECT | INTERFACE

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup SERVICE 54 ‣ _service
‣ _entities ‣ Schema “normalization” • Stub types • Resolvers for stub types

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup TOOLING 55

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup NO GATEWAY ALTERNATIVES 56

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup MANAGED SCHEMA 57 ‣
Validate schema changes against real queries ‣ Validate schema composition before the gateway ‣ “Live” schema update

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup APOLLO FEDERATION ✅ Compose
distributed graph ❓ Grained control over the ﬁnal schema ✅ Does not require boilerplate code ✅ Declarative management ✅ Stimulates conventions, standards 58

@bufo_alvarius @sponomarev Tver.IO, 9th Anniversary Meetup WARNING ⚠ New technology,
low adoption level ⚠ No support for subscriptions yet ⚠ Vendor lock (no self-hosted solutions for managed schema yet) 59

THANKS! Sergey Ponomarev evilmartians.com/chronicles @sponomarev @bufo_alvarius @evilmartians

GraphQL on Microservices Landscape

GraphQL on Microservices Landscape

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