Merge pull request #2037 from Davide-Gheri/feature/mercurius-federation-subscriptions

feat(): mercurius federation subscriptions

Author: kamilmysliwiec

packages/apollo/tests/e2e/code-first-federation.spec.ts

@@ -58,7 +58,7 @@ type Recipe implements IRecipe {
   description: String!
 }
 
-type Query @extends {
+type Query {
   findPost(id: Float!): Post!
   getPosts: [Post!]!
   search: [FederationSearchResultUnion!]! @deprecated(reason: \"test\")

packages/graphql/lib/federation/graphql-federation.factory.ts

@@ -25,7 +25,7 @@ import { gql } from 'graphql-tag';
 import { forEach, isEmpty } from 'lodash';
 import { GraphQLSchemaBuilder } from '../graphql-schema.builder';
 import { GraphQLSchemaHost } from '../graphql-schema.host';
-import { GqlModuleOptions } from '../interfaces';
+import { GqlModuleOptions, BuildFederatedSchemaOptions } from '../interfaces';
 import { ResolversExplorerService, ScalarsExplorerService } from '../services';
 import { extend } from '../utils';
 import { transformSchema } from '../utils/transform-schema.util';
@@ -41,13 +41,16 @@ export class GraphQLFederationFactory {
 
   async mergeWithSchema<T extends GqlModuleOptions>(
     options: T = {} as T,
+    buildFederatedSchema?: (
+      options: BuildFederatedSchemaOptions,
+    ) => GraphQLSchema,
   ): Promise<T> {
     const transformSchema = async (schema: GraphQLSchema) =>
       options.transformSchema ? options.transformSchema(schema) : schema;
 
     let schema: GraphQLSchema;
     if (options.autoSchemaFile) {
-      schema = await this.generateSchema(options);
+      schema = await this.generateSchema(options, buildFederatedSchema);
     } else if (isEmpty(options.typeDefs)) {
       schema = options.schema;
     } else {
@@ -81,19 +84,29 @@ export class GraphQLFederationFactory {
 
   private async generateSchema<T extends GqlModuleOptions>(
     options: T,
+    buildFederatedSchema?: (
+      options: BuildFederatedSchemaOptions,
+    ) => GraphQLSchema,
   ): Promise<GraphQLSchema> {
-    const { buildSubgraphSchema, printSubgraphSchema } = loadPackage(
+    const apolloSubgraph = loadPackage(
       '@apollo/subgraph',
       'ApolloFederation',
       () => require('@apollo/subgraph'),
     );
 
+    const printSubgraphSchema = apolloSubgraph.printSubgraphSchema;
+
+    if (!buildFederatedSchema) {
+      buildFederatedSchema = apolloSubgraph.buildSubgraphSchema;
+    }
+
     const autoGeneratedSchema: GraphQLSchema = await this.buildFederatedSchema(
       options.autoSchemaFile,
       options,
       this.resolversExplorerService.getAllCtors(),
     );
-    let executableSchema: GraphQLSchema = buildSubgraphSchema({
+
+    let executableSchema: GraphQLSchema = buildFederatedSchema({
       typeDefs: gql(printSubgraphSchema(autoGeneratedSchema)),
       resolvers: this.getResolvers(options.resolvers),
     });
@@ -170,21 +183,6 @@ export class GraphQLFederationFactory {
         forEach(
           fields,
           (value: GraphQLField<unknown, unknown>, key: string) => {
-            // Workaround for https://github.com/mercurius-js/mercurius/issues/273
-            if (key === '_service') {
-              value.resolve = function resolve() {
-                return {
-                  sdl: printSchema(autoGeneratedSchema)
-                    .replace('type Query {', 'type Query @extends {')
-                    .replace('type Mutation {', 'type Mutation @extends {')
-                    .replace(
-                      'type Subscription {',
-                      'type Subscription @extends {',
-                    ),
-                };
-              };
-            }
-
             const field = autoGeneratedObjectType.getFields()[key];
             if (!field) {
               return;

packages/graphql/lib/index.ts

@@ -18,3 +18,4 @@ export * from './tokens';
 export * from './type-factories';
 export * from './type-helpers';
 export * from './utils/extend.util';
+export * from './utils/transform-schema.util';

packages/graphql/lib/interfaces/build-federated-schema-options.interface.ts

@@ -0,0 +1,6 @@
+import { DocumentNode } from 'graphql';
+
+export interface BuildFederatedSchemaOptions {
+  typeDefs: DocumentNode;
+  resolvers: any;
+}

packages/graphql/lib/interfaces/index.ts

@@ -13,3 +13,4 @@ export {
 export * from './graphql-driver.interface';
 export * from './resolve-type-fn.interface';
 export * from './return-type-func.interface';
+export * from './build-federated-schema-options.interface';

packages/mercurius/lib/drivers/mercurius-federation.driver.ts

@@ -8,6 +8,7 @@ import { printSchema } from 'graphql';
 import { IncomingMessage, Server, ServerResponse } from 'http';
 import mercurius from 'mercurius';
 import { MercuriusDriverConfig } from '../interfaces/mercurius-driver-config.interface';
+import { buildMercuriusFederatedSchema } from '../utils/build-mercurius-federated-schema.util';
 
 @Injectable()
 export class MercuriusFederationDriver extends AbstractGraphQLDriver<MercuriusDriverConfig> {
@@ -29,6 +30,7 @@ export class MercuriusFederationDriver extends AbstractGraphQLDriver<MercuriusDr
   public async start(options: MercuriusDriverConfig) {
     const adapterOptions = await this.graphqlFederationFactory.mergeWithSchema(
       options,
+      buildMercuriusFederatedSchema,
     );
 
     if (adapterOptions.definitions && adapterOptions.definitions.path) {

packages/mercurius/lib/utils/build-mercurius-federated-schema.util.ts

@@ -0,0 +1,52 @@
+import { loadPackage } from '@nestjs/common/utils/load-package.util';
+import { transformSchema } from '@nestjs/graphql';
+import { BuildFederatedSchemaOptions } from '@nestjs/graphql';
+import { GraphQLSchema, isObjectType, buildASTSchema } from 'graphql';
+import { forEach } from 'lodash';
+
+export function buildMercuriusFederatedSchema({
+  typeDefs,
+  resolvers,
+}: BuildFederatedSchemaOptions) {
+  const { buildSubgraphSchema, printSubgraphSchema } = loadPackage(
+    '@apollo/subgraph',
+    'MercuriusFederation',
+    () => require('@apollo/subgraph'),
+  );
+  let executableSchema: GraphQLSchema = buildSubgraphSchema({
+    typeDefs,
+    resolvers,
+  });
+
+  const subscriptionResolvers = resolvers.Subscription;
+  executableSchema = transformSchema(executableSchema, (type) => {
+    if (isObjectType(type)) {
+      const isSubscription = type.name === 'Subscription';
+      forEach(type.getFields(), (value, key) => {
+        if (isSubscription && subscriptionResolvers) {
+          const resolver = subscriptionResolvers[key];
+          if (resolver && !value.subscribe) {
+            value.subscribe = resolver.subscribe;
+          }
+        } else if (key === '_service') {
+          // Workaround for https://github.com/mercurius-js/mercurius/issues/273
+          value.resolve = function resolve() {
+            return {
+              sdl: printSubgraphSchema(
+                buildASTSchema(typeDefs, {
+                  assumeValid: true,
+                }),
+              )
+                .replace('type Query {', 'type Query @extends {')
+                .replace('type Mutation {', 'type Mutation @extends {')
+                .replace('type Subscription {', 'type Subscription @extends {'),
+            };
+          };
+        }
+      });
+    }
+    return type;
+  });
+
+  return executableSchema;
+}

packages/mercurius/tests/subscriptions-federation/app/app.module.ts

@@ -0,0 +1,29 @@
+import { Module } from '@nestjs/common';
+import { DynamicModule } from '@nestjs/common/interfaces';
+import { GraphQLModule } from '@nestjs/graphql';
+import { MercuriusFederationDriver, MercuriusFederationDriverConfig } from '../../../lib';
+import { NotificationModule } from './notification.module';
+
+export type AppModuleConfig = {
+  context?: MercuriusFederationDriverConfig['context'];
+  subscription?: MercuriusFederationDriverConfig['subscription'];
+};
+
+@Module({})
+export class AppModule {
+  static forRoot(options?: AppModuleConfig): DynamicModule {
+    return {
+      module: AppModule,
+      imports: [
+        NotificationModule,
+        GraphQLModule.forRoot<MercuriusFederationDriverConfig>({
+          driver: MercuriusFederationDriver,
+          context: options?.context,
+          federationMetadata: true,
+          autoSchemaFile: true,
+          subscription: options?.subscription,
+        }),
+      ],
+    };
+  }
+}

packages/mercurius/tests/subscriptions-federation/app/auth.guard.ts

@@ -0,0 +1,10 @@
+import { CanActivate, ExecutionContext, Injectable } from '@nestjs/common';
+import { GqlExecutionContext } from '@nestjs/graphql';
+
+@Injectable()
+export class AuthGuard implements CanActivate {
+  canActivate(context: ExecutionContext): boolean {
+    const ctx = GqlExecutionContext.create(context).getContext();
+    return !!ctx.user?.startsWith?.('test');
+  }
+}

packages/mercurius/tests/subscriptions-federation/app/notification.module.ts

@@ -0,0 +1,7 @@
+import { Module } from '@nestjs/common';
+import { NotificationResolver } from './notification.resolver';
+
+@Module({
+  providers: [NotificationResolver],
+})
+export class NotificationModule {}