Google App Engine backend service(module) with Java

Question

I am a newbie in Google App Engine. I am trying to create a service (previously called "modules") in Eclipse in Java. I didn't find any resources which shows a step-by-step guide to create a service for app-engine in eclipse or any other IDE. What are the configuration files I need to take care of?

I have tried to find docs on cloud platform and everything says about having front-end. There are articles about micro-service architecture and migrate an existing app . But I don't have an existing app. Every tutorial talks about cloning an hello world app and deploying it which shows hello world with appspot url. But didn't found anything for the service(module).

The service I am trying to create does not have a front-end. It just runs in the background and watch the database and sends emails and notifications to the users based on database change. This is not an API and there isn't any request-response architecture.

How can I achieve this?

Any reference material or samples which can guide me to the right direction?

Answer 1

To set up an App Engine project you could have a look at Romin Irani tutorials which are very good ( https://rominirani.com/google-cloud-endpoints-tutorial-part-1-b571ad6c7cd2#.qclm8gyd9 ).

There is also a free MOOC on Udacity which covers Endpoints with Eclipse: https://www.udacity.com/course/developing-scalable-apps-in-java--ud859

Both cover the building of Endpoints and querying them from front-ends, which I understand is not your goal. But the Udacity course covers Cron jobs and sending of emails (both in Lesson 5), which is what you would use for your needs. See also https://cloud.google.com/appengine/docs/java/config/cron#creating_a_cron_job which is very good Google documentation.

So in a nutshell: I would start by Romin's tutorial to understand Eclipse set-up and main concepts, then follow Udacity MOOC (especially part on Cron and mail) and then dive into the Google doc for the fine tuning of your development.

Last but not least, for sending emails, nowadays, Google advice to use Sengrid. But I think it worth following the Udacity lesson on sending email, even if you switch from native email sending to Sendgrid later on. Again, the doc is complete and clear.

Hope this helps!