Program: Full-Stack implementation of a simple Mail Publisher application

Technologies: Spring Boot, VueJs, SendGrid & MailJet API Integration, Gradle

Task Description

Implement a complete end-2-end email publisher sample with independent frontent & backend with integration with email publishing providers like SendGrid & MailJet.

With the kind of strategic fallback mechanism available, we can ensure that email that is published to the target recipients are delivered by one of the configured providers. There might be cases if all the providers are down. In such cases, error message is shown for the same.

Steps to Test the app

It's ideal to use Unix stack for testing this out. But we can get it working with Windows by tweaking code if any issue arises
Clone this repository
Ensure Java 8 SDK is installed and gradle is downloaded and configured in the system path and working
Run gradle build from the project root folder to build both API & UI Projects
- This would build UI & API project in sequence and build the final jar file available for execution to test the application
- If any issues observed during node modules download for UI project, fixing them would be trivial by running npm or yarn commands in ui folder
Ensure that api jar is created successfully post gradle build is successfully completed.
Execute the following command to kickstart the spring boot application which will start the mail publisher example

java -jar api-0.0.1-SNAPSHOT.jar --sendgrid.api.key="Bearer <SENDGRID_API_KEY>" --mailjet.api.key.public="<MAILJET_PUBLIC_API_KEY>" --mailjet.api.key.private="<MAILJET_PRIVATE_API_KEY> --mail.publisher.from.default="<EMAILADDRESS_OF_PUBLISHER>"

Replace Placeholders for SendGrid & MailJet API Keys and email address if publisher to test the application

Accessing http://localhost:8080 will open the email publisher UI client application
UI artifacts are copied to spring boot src/resources/static folder during build process and thus available as single artefact.

Test Cases

Publish mail without mandatory fields and verify if appropriate error messages are displayed
Publish mail with one or more recipients in To, Cc & Bcc fields without subject and email body
Publish mail with one or more recipients in To, Cc & Bcc fields with valid subject and email body

TODO's

Test class implementation by mocking Spring beans using jUnit & Mockito to validate rest interface for all possible test cases
Unit & e2e test cases for User Interface
Containerizing the application with Docker
CI using Jenkins and CD using Terraform on AWS

Observations

SendGrid is not able to publish emails to outlook.com. Emails published to gmail.com are getting landed in spam/junk folder
MailJet will allow publishing the emails with the configured from address & mapped public and private keys only. API requests fail if there is deviation on the same.
MailJet is able to publish emails to outlook.com landing them to spam/junk folder. Emails are not delivered to gmail.com
Ensure to provide valid subject & email content to have the emails delivered successfully to your inbox.
Either of the services will get suspended during review process as we create test accounts to evaluate such services.
Fallback to other providers by implementing MailProvider interface. Below are few alternatives
- MailGun
- AWS Simple Email Service
- Agile CRM
- Mail Chimp
- Campayn
- etc...

Screenshorts

User Interface of Email Publisher client
Validatin errors displayed when email form is published without providing mandatory fields
Success message displayed when email is published successfully
Sample stats retrieved from SendGrid