apollo-server: Support onHealthCheck in ApolloServer constructor. (…

…#2672)

Support `onHealthCheck` in the `ApolloServer` constructor for `apollo-server` (the "quick start" package) in the same way as `cors` is supported.  This contrasts with the `-express`, `-hapi`, etc. variations which accept this parameter via their `applyMiddleware` methods and will remain as-is.

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 # vNEXT
 
+- `apollo-server`: Support `onHealthCheck` in the `ApolloServer` constructor in the same way as `cors` is supported.  This contrasts with the `-express`, `-hapi`, etc. variations which accept this parameter via their `applyMiddleware` methods and will remain as-is.  [PR #2672](https://github.com/apollographql/apollo-server/pull/2672)
 - core: Expose SHA-256 hex hash digest of the Engine API key to plugins, when available, as `engine.apiKeyHash`. [PR# 2685](https://github.com/apollographql/apollo-server/pull/2685)
 - `apollo-datasource-rest`: If another `Content-type` is already set on the response, don't overwrite it with `application/json`, allowing the user's initial `Content-type` to prevail. [PR #2520](https://github.com/apollographql/apollo-server/issues/2035)
 

packages/apollo-server/src/index.ts

@@ -25,14 +25,17 @@ export interface ServerInfo {
 export class ApolloServer extends ApolloServerBase {
   private httpServer?: http.Server;
   private cors?: CorsOptions | boolean;
+  private onHealthCheck?: (req: express.Request) => Promise<any>;
 
   constructor(
     config: ApolloServerExpressConfig & {
       cors?: CorsOptions | boolean;
+      onHealthCheck?: (req: express.Request) => Promise<any>;
     },
   ) {
     super(config);
     this.cors = config && config.cors;
+    this.onHealthCheck = config && config.onHealthCheck;
   }
 
   private createServerInfo(
@@ -90,6 +93,7 @@ export class ApolloServer extends ApolloServerBase {
       app,
       path: '/',
       bodyParserConfig: { limit: '50mb' },
+      onHealthCheck: this.onHealthCheck,
       cors:
         typeof this.cors !== 'undefined'
           ? this.cors