Add check function

HTTP function to check whether the email server is ready to accept
messages.

index.js

@@ -1,8 +1,46 @@
 'use strict';
 
+const nodemailer = require('nodemailer');
+const bunyan = require('bunyan');
+
 const config = require('./config.json');
 
+
+/**
+ *
+ */
 exports.ping = (request, response) => {
   // Everything is ok
   response.status(200).send('Pong!');
 };
+
+/**
+ *
+ */
+function getTransporter() {
+  const logger = bunyan.createLogger({ name: 'nodemailer' });
+  logger.level('trace');
+
+  return nodemailer.createTransport({
+    service: config.transport.service,
+    auth: config.transport.auth,
+    logger,
+    debug: true
+  });
+}
+
+/**
+ *
+ */
+exports.check = (request, response) => {
+  const transporter = getTransporter();
+
+  transporter.verify((error, success) => {
+    if (error) {
+      console.log(`Error: ${error}`);
+      response.status(400).send('Error: Server is not ready to accept messages');
+    } else {
+      response.status(200).send('Success: Server ready to take our messages');
+    }
+  });
+}

package.json

@@ -17,6 +17,8 @@
     "remove": "serverless remove"
   },
   "dependencies": {
+    "bunyan": "^1.8.12",
+    "nodemailer": "^4.4.2",
     "serverless-google-cloudfunctions": "^1.1.0"
   }
 }

serverless.yml

@@ -1,13 +1,13 @@
-service: ${file(./config.json):SERVICE_ID}
+service: ${file(./config.json):service_id}
 
 provider:
   name: google
   runtime: nodejs
   memorySize: 256
   timeout: 60s
-  project: ${file(./config.json):PROJECT_ID}
+  project: ${file(./config.json):project_id}
   # the path to the credentials file needs to be absolute
-  credentials: ${file(./config.json):CREDENTIALS_FILE}
+  credentials: ${file(./config.json):credentials_file}
 
 plugins:
   - serverless-google-cloudfunctions
@@ -28,24 +28,9 @@ functions:
     events:
       - http: path
 
-  # NOTE: the following uses an "event" event (pubSub event in this case).
-  # Please create the corresponding resources in the Google Cloud
-  # before deploying this service through Serverless
-
-  #second:
-  #  handler: event
-  #  events:
-  #    - event:
-  #        eventType: providers/cloud.pubsub/eventTypes/topic.publish
-  #        resource: projects/*/topics/my-topic
-
-# you can define resources, templates etc. the same way you would in a
-# Google Cloud deployment configuration
-#resources:
-#  resources:
-#    - type: storage.v1.bucket
-#      name: my-serverless-service-bucket
-#  imports:
-#    - path: my_template.jinja
+  check:
+    handler: check
+    events:
+      - http: path
 
 frameworkVersion: "=1.25.0"