Set x-aws-lambda-request-id header

Author: janaz

src/lambda.ts

@@ -8,7 +8,8 @@ declare namespace handler {
   type APIGatewayEvent = apigw.APIGatewayEvent;
   type APIGatewayResponse = apigw.LambdaResponse;
   type LambdaResponse = apigw.LambdaResponse;
-  type APIGatewayEventHandler = (event: handler.APIGatewayEvent) => Promise<handler.LambdaResponse>
+  type LambdaContext = apigw.LambdaContext;
+  type APIGatewayEventHandler = (event: handler.APIGatewayEvent, context?: handler.LambdaContext) => Promise<handler.LambdaResponse>
 };
 
 const eventWithMultiValueHeaders = (event: handler.APIGatewayEvent): boolean => {
@@ -17,15 +18,15 @@ const eventWithMultiValueHeaders = (event: handler.APIGatewayEvent): boolean =>
 
 const handlerPromise = (appPromiseFn: () => Promise<RequestListener>): handler.APIGatewayEventHandler => {
   let _p: Promise<RequestListener> | null = null;
-  return event => {
+  return (event, ctx) => {
     if (!_p) {
       _p = appPromiseFn();
     }
     return _p
       .then(app => {
         return Promise.resolve()
           .then(() => {
-            const reqOptions = eventToRequestOptions(event);
+            const reqOptions = eventToRequestOptions(event, ctx);
             const appHandler = inProcessRequestHandler(app);
             return appHandler(reqOptions)
           })

test/integration.test.ts

@@ -195,6 +195,12 @@ describe('integration', () => {
     });
   });
 
+  it('sets x-aws-lambda-request-id header with context request id', () => {
+    return handler(event, {awsRequestId: 'req-id'}).then(response => {
+      expect(response.multiValueHeaders!['x-aws-lambda-request-id']).toEqual('req-id');
+    });
+  });
+
   it('works with compressed response', () => {
     const myEvent = {
       path: "/static/big.html",