Add gateway version to schema extensions

gateway-js/src/__tests__/gateway/extensions.test.ts

@@ -0,0 +1,37 @@
+import { ApolloGateway } from '@apollo/gateway';
+import resolvable from '@josephg/resolvable';
+import { GraphQLSchema } from 'graphql';
+import { getTestingSupergraphSdl } from '../execution-utils';
+const { version } = require('../../../package.json');
+
+describe('addExtensions', () => {
+  let gateway: ApolloGateway;
+
+  beforeEach(() => {
+    gateway = new ApolloGateway({
+      supergraphSdl: getTestingSupergraphSdl(),
+    });
+  });
+
+  afterEach(async () => {
+    await gateway.stop();
+  });
+
+  it('has extensions on loaded schemas', async () => {
+    const { schema } = await gateway.load();
+    expect(schema.extensions).toEqual({ apollo: { gateway: { version: version } } });
+  });
+
+  it('has extensions on schema updates', async () => {
+    const schemaChangeBlocker = resolvable<{
+      apiSchema: GraphQLSchema;
+      coreSupergraphSdl: string;
+    }>();
+
+    gateway.onSchemaLoadOrUpdate(schemaChangeBlocker.resolve);
+    gateway.load();
+
+    const { apiSchema } = await schemaChangeBlocker;
+    expect(apiSchema.extensions).toEqual({ apollo: { gateway: { version: version } } });
+  });
+});

gateway-js/src/index.ts

@@ -54,6 +54,7 @@ import {
 import { SpanStatusCode } from '@opentelemetry/api';
 import { OpenTelemetrySpanNames, tracer } from './utilities/opentelemetry';
 import { createHash } from './utilities/createHash';
+import { addExtensions } from './schema-helper/addExtensions';
 import {
   IntrospectAndCompose,
   UplinkFetcher,
@@ -431,6 +432,8 @@ export class ApolloGateway implements GraphQLService {
       }`,
     );
 
+    addExtensions(this.schema!);
+
     return {
       schema: this.schema!,
       executor: this.executor,
@@ -640,8 +643,8 @@ export class ApolloGateway implements GraphQLService {
   ): void {
     if (this.queryPlanStore) this.queryPlanStore.flush();
     this.apiSchema = coreSchema.toAPISchema();
-    this.schema = wrapSchemaWithAliasResolver(
-      this.apiSchema.toGraphQLJSSchema(),
+    this.schema = addExtensions(
+      wrapSchemaWithAliasResolver(this.apiSchema.toGraphQLJSSchema()),
     );
     this.queryPlanner = new QueryPlanner(coreSchema);
 

gateway-js/src/schema-helper/__tests__/addExtensions.test.ts

@@ -0,0 +1,11 @@
+import { buildSchema } from 'graphql';
+import { addExtensions } from '../addExtensions';
+const { version } = require('../../../package.json');
+
+describe('addExtensions', () => {
+  it('adds gateway extensions to a schema', async () => {
+    const schema = buildSchema('type Query { hello: String }');
+    expect(schema.extensions).toEqual({});
+    expect(addExtensions(schema).extensions).toEqual({ apollo: { gateway: { version: version } } });
+  });
+});

gateway-js/src/schema-helper/addExtensions.ts

@@ -0,0 +1,17 @@
+import { GraphQLSchema } from 'graphql';
+const { version } = require('../../package.json');
+
+export function addExtensions(schema: GraphQLSchema): GraphQLSchema {
+  schema.extensions = {
+    ...schema.extensions,
+    apollo: {
+      ...schema.extensions.apollo,
+      gateway: {
+        ...schema.extensions.apollo?.gateway,
+        version,
+      }
+    },
+  };
+
+  return schema;
+}

gateway-js/src/typings/graphql.ts

@@ -10,6 +10,10 @@ interface ApolloSubgraphExtensions<TContext> {
   resolveReference?: GraphQLReferenceResolver<TContext>;
 }
 
+interface ApolloGatewayExtensions {
+  version?: String;
+}
+
 declare module 'graphql/type/definition' {
   interface GraphQLObjectTypeExtensions<_TSource = any, _TContext = any> {
     apollo?: {
@@ -29,3 +33,11 @@ declare module 'graphql/type/definition' {
     }
   }
 }
+
+declare module 'graphql/type/schema' {
+  interface GraphQLSchemaExtensions {
+    apollo?: {
+      gateway?: ApolloGatewayExtensions;
+    }
+  }
+}

gateway-js/tsconfig.test.json

@@ -3,7 +3,11 @@
   "files": [
     "./src/__tests__/testSetup.ts"
   ],
-  "include": ["**/__tests__/**/*", "**/__mocks__/**/*"],
+  "include": [
+    "src/typings/*",
+    "**/__tests__/**/*",
+    "**/__mocks__/**/*"
+  ],
   "references": [
     { "path": "./" },
     { "path": "../federation-integration-testsuite-js" },

subgraph-js/tsconfig.test.json

@@ -3,7 +3,10 @@
   "files": [
     "./src/__tests__/testSetup.ts"
   ],
-  "include": ["**/__tests__/**/*"],
+  "include": [
+    "src/schemaExtensions.ts",
+    "**/__tests__/**/*"
+  ],
   "references": [
     { "path": "./" },
   ]