Gateway: minimize downstream requests (#3737)

* Minimize downstream requests

Use graphql-js's `stripIgnoredCharacters` utility to minimize query
body size over the wire from the gateway to downstream services.

* Update changelog

Author: trevor-scheer

packages/apollo-gateway/CHANGELOG.md

@@ -6,6 +6,7 @@
 
 * Reduce interface expansion for types contained to a single service [#3582](https://github.com/apollographql/apollo-server/pull/3582)
 * Instantiate one `CachedFetcher` per gateway instance.  This resolves a condition where multiple federated gateways would utilize the same cache store could result in an `Expected undefined to be a GraphQLSchema` error. [#3704](https://github.com/apollographql/apollo-server/pull/3704)
+* Gateway: minimize downstream request size [#3737](https://github.com/apollographql/apollo-server/pull/3737)
 
 # v0.11.6
 

packages/apollo-gateway/src/__tests__/executeQueryPlan.test.ts

@@ -144,7 +144,7 @@ describe('executeQueryPlan', () => {
       );
       expect(response).toHaveProperty(
         'errors.0.extensions.query',
-        '{\n  me {\n    name\n  }\n}',
+        '{me{name}}',
       );
       expect(response).toHaveProperty('errors.0.extensions.variables', {});
     });

packages/apollo-gateway/src/__tests__/gateway/buildService.test.ts

@@ -85,11 +85,7 @@ it('correctly passes the context from ApolloServer to datasources', async () =>
   expect(fetch).toHaveFetched({
     url: 'https://api.example.com/foo',
     body: {
-      query: `{
-  me {
-    username
-  }
-}`,
+      query: `{me{username}}`,
       variables: {},
     },
     headers: {

packages/apollo-gateway/src/executeQueryPlan.ts

@@ -14,6 +14,7 @@ import {
   TypeNameMetaFieldDef,
   VariableDefinitionNode,
   GraphQLFieldResolver,
+  stripIgnoredCharacters,
 } from 'graphql';
 import { Trace, google } from 'apollo-engine-reporting-protobuf';
 import { GraphQLDataSource } from './datasources/types';
@@ -289,7 +290,7 @@ async function executeFetch<TContext>(
     operation: OperationDefinitionNode,
     variables: Record<string, any>,
   ): Promise<ResultMap | void | null> {
-    const source = print(operation);
+    const source = stripIgnoredCharacters(print(operation));
     // We declare this as 'any' because it is missing url and method, which
     // GraphQLRequest.http is supposed to have if it exists.
     let http: any;