Enable the Engine proxy and observe queries on Engine #graphql-in-production

[API]

### Instructions
1. Create a new Engine instance and put it in front of your app
2. Start the Engine proxy server
3. Add the Engine middleware to the Express server
4. Confirm that the app works as before
5. Go to Engine and observe your queries! Compare database fields with external api calls, etc.
---
### Tips
- Edit `api/src/server/index.js` and `api/.env`
- You'll need your Engine API Key that you got at the beginning of the training
- Change the app's port number so the proxy can accept network requests on its behalf.
- Look at the previous slides for inspiration

### Docs
- [Engine docs](http://engine-docs.apollographql.com/)
- [Engine package](https://github.com/apollographql/apollo-engine-js)
- [Engine website](https://engine.apollographql.com/)

Author: rdickert

api/src/server/index.js

@@ -14,6 +14,7 @@ import {
 import { createServer } from 'http';
 import { SubscriptionServer } from 'subscriptions-transport-ws';
 import { execute, subscribe } from 'graphql';
+import { Engine } from 'apollo-engine';
 import passport from 'passport';
 import typeDefs from '../typeDefs';
 import resolvers from '../resolvers';
@@ -28,6 +29,7 @@ const {
   WS_PORT = parseInt(PORT, 10) + 1,
   MONGO_PORT = parseInt(PORT, 10) + 2,
   MONGO_URL = `mongodb://localhost:${MONGO_PORT}/database`,
+  ENGINE_API_KEY,
 } = process.env;
 
 const startServer = async () => {
@@ -75,6 +77,22 @@ const startServer = async () => {
     }),
   });
 
+  // IMPORTANT: you also need to set the port in api/.env to PORT=9000 in
+
+  const engine = new Engine({
+    engineConfig: {
+      apiKey: ENGINE_API_KEY,
+      frontends: [
+        {
+          host: '127.0.0.1',
+          port: 8080,
+          endpoint: '/graphql',
+        },
+      ],
+    },
+  });
+  await engine.start();
+
   const db = await MongoClient.connect(MONGO_URL);
 
   const createContext = () => ({
@@ -87,6 +105,8 @@ const startServer = async () => {
 
   const server = express();
 
+  server.use(engine.expressMiddleware());
+
   server.use(cors());
 
   server.use(bodyParser.json());