Merge pull request #29 from fterh/notify-errors

Notify user of errors

functions/receipt.ts

@@ -1,37 +1,61 @@
-"use strict";
-
 import { S3 } from "aws-sdk";
 import { S3Event } from "aws-lambda";
 import { simpleParser } from "mailparser";
+import { email, operationalDomain } from "../lib/env";
 import extractEmailAliases from "../lib/extractEmailAliases";
 import processAliases from "../lib/processAliases";
+import sendEmail from "../lib/sendEmail";
 
-export const handler = async (event: S3Event) => {
-  console.log(`Received incoming email; key=${event.Records[0].s3.object.key}`);
+const getRecordData = async (
+  request: S3.GetObjectRequest,
+  s3: S3
+): Promise<Buffer> => {
+  console.log("Fetching email from S3 storage");
+  return (await s3.getObject(request).promise()).Body as Buffer;
+};
+
+const deleteRecord = async (
+  request: S3.DeleteObjectRequest,
+  s3: S3
+): Promise<void> => {
+  console.log("Deleting email from S3 storage");
+  await s3.deleteObject(request).promise();
+  console.log("Deleted email from S3 storage");
+};
+
+const notifyUserOfError = async (err: any): Promise<void> => {
+  if (err instanceof Error) {
+    console.error(err, err.stack);
+  } else {
+    console.error(err);
+  }
 
-  const s3 = new S3({
-    apiVersion: "2006-03-01",
-    region: process.env.AWSREGION // TODO check if this should be AWS_REGION instead
+  await sendEmail({
+    from: `heimdall@${operationalDomain}`,
+    to: email,
+    subject: "Oops, something went wrong!",
+    text: `An error has occurred:\n\n${err}\n\nCheck the logs for more information.`
   });
+};
 
+export const handler = async (event: S3Event) => {
   const record = event.Records[0];
+  console.log(`Received incoming email (key=${record.s3.object.key})`);
+
+  const s3 = new S3();
   const request = {
     Bucket: record.s3.bucket.name,
     Key: record.s3.object.key
   };
 
   try {
-    const data = (await s3.getObject(request).promise()).Body as Buffer;
+    const data = await getRecordData(request, s3);
     const email = await simpleParser(data);
     const aliases = extractEmailAliases(email);
     await processAliases(aliases, email);
 
-    // Delete the email from S3 only after successfully processing it
-    console.log("Deleting email from S3 storage");
-    await s3.deleteObject(request).promise();
-    console.log("Deleted email from S3 storage");
+    await deleteRecord(request, s3);
   } catch (err) {
-    console.error(err);
-    return err;
+    await notifyUserOfError(err);
   }
 };

tests/functions/receipt.test.ts

@@ -2,6 +2,9 @@ import path from "path";
 import { S3EventRecord } from "aws-lambda";
 import * as AWSMock from "aws-sdk-mock";
 import { handler } from "../../functions/receipt";
+import { email, operationalDomain } from "../../lib/env";
+import processAliases from "../../lib/processAliases";
+import sendEmail from "../../lib/sendEmail";
 
 type Callback = (err: any, data: any) => void;
 
@@ -12,13 +15,24 @@ jest.mock("mailparser", () => {
     }
   };
 });
-jest.mock("../../lib/commands");
 jest.mock("../../lib/extractEmailAliases");
-jest.mock("../../lib/forwardInboundOrOutbound");
+jest.mock("../../lib/processAliases");
+jest.mock("../../lib/sendEmail");
+
+const _processAliases = processAliases as jest.Mock;
+const _sendEmail = sendEmail as jest.Mock;
+
+const deleteObjectSpy = jest.fn();
 
 beforeEach(() => {
   // Fix: https://github.com/dwyl/aws-sdk-mock/issues/145
   AWSMock.setSDK(path.resolve(__dirname, "../../node_modules/aws-sdk"));
+
+  AWSMock.mock("S3", "getObject", { Body: Buffer.from("test data") });
+  AWSMock.mock("S3", "deleteObject", (params: any, callback: Callback) => {
+    deleteObjectSpy();
+    callback(null, null);
+  });
 });
 
 afterEach(() => {
@@ -62,13 +76,26 @@ const testS3EventRecord: S3EventRecord = {
 };
 
 it("should delete the email after successfully processing it", async () => {
-  const spy = jest.fn();
-  AWSMock.mock("S3", "getObject", { Body: Buffer.from("test data") });
-  AWSMock.mock("S3", "deleteObject", (params: any, callback: Callback) => {
-    spy();
-    callback(null, null);
+  await handler({ Records: [testS3EventRecord] });
+
+  expect(deleteObjectSpy).toHaveBeenCalledTimes(1);
+});
+
+it("should not delete the email and also notify the user in the event of errors", async () => {
+  _processAliases.mockImplementation(async () => {
+    throw new Error();
   });
 
   await handler({ Records: [testS3EventRecord] });
-  expect(spy).toHaveBeenCalledTimes(1);
+
+  expect(deleteObjectSpy).not.toBeCalled();
+  expect(_sendEmail).toHaveBeenCalledTimes(1);
+  expect(_sendEmail.mock.calls[0][0].from).toBe(
+    `heimdall@${operationalDomain}`
+  );
+  expect(_sendEmail.mock.calls[0][0].to).toBe(email);
+  expect(_sendEmail.mock.calls[0][0].subject).toBe(
+    "Oops, something went wrong!"
+  );
+  expect(_sendEmail.mock.calls[0][0].text).toContain("An error has occurred:");
 });