Types and signature cleanup

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

@@ -1,4 +1,4 @@
-import { ApolloGateway } from '@apollo/gateway';
+import { ApolloGateway, SupergraphSdlUpdateFunction } from '@apollo/gateway';
 import { fixturesWithUpdate } from 'apollo-federation-integration-testsuite';
 import { createHash } from 'crypto';
 import { ApolloServer } from 'apollo-server';
@@ -112,9 +112,9 @@ describe('Using supergraphSdl dynamic configuration', () => {
     const [userPromise, resolveSupergraph] =
       waitUntil<{ supergraphSdl: string }>();
 
-    let userUpdateFn: (updatedSupergraphSdl: string) => Promise<void>;
+    let userUpdateFn: SupergraphSdlUpdateFunction;
     const gateway = new ApolloGateway({
-      async supergraphSdl(update) {
+      async supergraphSdl({ update }) {
         userUpdateFn = update;
         return userPromise;
       },
@@ -179,9 +179,7 @@ describe('Using supergraphSdl dynamic configuration', () => {
 
     it('gracefully handles Promise rejections from user `cleanup` function', async () => {
       const rejectionMessage = 'thrown from cleanup function';
-      const cleanup = jest.fn(() =>
-        Promise.reject(rejectionMessage),
-      );
+      const cleanup = jest.fn(() => Promise.reject(rejectionMessage));
       const gateway = new ApolloGateway({
         async supergraphSdl() {
           return {

gateway-js/src/config.ts

@@ -173,9 +173,16 @@ export function isManuallyManagedSupergraphSdlGatewayConfig(
     'supergraphSdl' in config && typeof config.supergraphSdl === 'function'
   );
 }
+
+export interface SupergraphSdlUpdateFunction {
+  (updatedSupergraphSdl: string): Promise<void>
+}
+export interface SupergraphSdlUpdateOptions {
+  update: SupergraphSdlUpdateFunction;
+}
 interface ManuallyManagedSupergraphSdlGatewayConfig extends GatewayConfigBase {
   supergraphSdl: (
-    update: (updatedSupergraphSdl: string) => Promise<void>,
+    opts: SupergraphSdlUpdateOptions,
   ) => Promise<{ supergraphSdl: string; cleanup?: () => Promise<void> }>;
 }
 
@@ -231,7 +238,7 @@ export function isManuallyManagedConfig(
   config: GatewayConfig,
 ): config is ManuallyManagedGatewayConfig {
   return (
-    ('supergraphSdl' in config && typeof config.supergraphSdl === 'function') ||
+    isManuallyManagedSupergraphSdlGatewayConfig(config) ||
     'experimental_updateServiceDefinitions' in config ||
     'experimental_updateSupergraphSdl' in config
   );

gateway-js/src/index.ts

@@ -261,7 +261,7 @@ export class ApolloGateway implements GraphQLService {
           this.config.experimental_updateServiceDefinitions;
       } else if (isManuallyManagedSupergraphSdlGatewayConfig(this.config)) {
         this.manualConfigPromise = this.config
-          .supergraphSdl(this.updateWithSupergraphSdl.bind(this))
+          .supergraphSdl({ update: this.updateWithSupergraphSdl.bind(this) })
           .catch((e) => {
             // Not swallowing the error here results in an uncaught rejection.
             // An error will be thrown when this promise resolves to nothing.
@@ -613,12 +613,6 @@ export class ApolloGateway implements GraphQLService {
   private async updateWithSupergraphSdl(
     result: SupergraphSdlUpdate | string,
   ): Promise<void> {
-    if (typeof result === 'string') {
-    } else if (result.id === this.compositionId) {
-      this.logger.debug('No change in composition since last check.');
-      return;
-    }
-
     const supergraphSdl =
       typeof result === 'string' ? result : result.supergraphSdl;
 
@@ -627,6 +621,11 @@ export class ApolloGateway implements GraphQLService {
         ? createHash('sha256').update(result).digest('hex')
         : result.id;
 
+    if (id === this.compositionId) {
+      this.logger.debug('No change in composition since last check.');
+      return;
+    }
+
     // TODO(trevor): #580 redundant parse
     // This may throw, so we'll calculate early (specifically before making any updates)
     // In the case that it throws, the gateway will:
@@ -1413,3 +1412,8 @@ export {
 };
 
 export * from './datasources';
+
+export {
+  SupergraphSdlUpdateOptions,
+  SupergraphSdlUpdateFunction,
+} from './config';