Falcon Test Task

This project is a test task - mostly just to get acquainted with some new technologies. It includes a few major components:

• SpringBoot
• RabbitMQ
• Redis
• MySQL (using jdbcTemplate)
• STOMP Protocol & Websockets
• Magic.

What does this project do:

• It has two API endpoints - one for pushing a sample JSON through the queues, and another - for getting all the data out from the MySQL database
• The moment a JSON request arrives at the API endpoint, its stringified content is pushed into a Redis server with an unique key
• There is a @Scheduled task that pumps automated messages into the queue, but those messages are deliberately not allowed in the Redis
• Both API endpoints are available through a (not so) friendly interface at http://localhost:8080

So how should I build this project?

For maximum ease and convenience (and bonus points), I made sure it can be started using only two simple lines in the Terminal:

$ docker-compose up -d
$ mvn spring-boot:run

I guess the fear I had from Docker was completely unnecessary - it turned out to be a great tool, easy to use, that helps you keep your computer a less messy place.

Anything special?

There are a few things I would like to point out, since I decided they would be good ideas for this task:

• Since we are dealing with a REST API here, we know people tend to abuse those (especially when free). That's why it has a LimitFilter, a Java class that keeps people doing more than 10 requests for a given time away with response code 429 (Too Many Requests)
• It is not explicitly written in the task, but I believe anyone who doesn't take measures against DB-killer queries should be punished. That's why the API endpoint that gathers all the rows from the MySQL table has a limit of 20 rows per page. Luckily, the (terrible) user interface allows us to change the page with ease
• I experimented a lot, pushing broken JSON and empty values into those queues and caches. In the end, I decided that a broken JSON or empty values should not be allowed into our datastore. The MessageModel ignores unknown JsonProperties and let's go if parsing a shitty JSON turns out to be too heavy task - we got plenty of those
• Every new message is pushed with ID = -1. It gets its own unique ID only after making it to the MySQL Server, that takes care of the auto-increment. Speaking of database operations - except for pushing messages until we run out of disk space - we can't really manipulate the data in the MySQL (or anywhere, to be fair) - but I decided that going there would be an overkill.
• I was very amazed to find out that RESTful APIs should return HTTP Status 201 CREATED when successfully inserting object(s). I modified my method to do so.

The only part I decided not to commit is the tests. I gave them a try, just to complete every single point in the task... but it did not work out very well. My imagination got lazy like a programmer after a big lunch and I came up with only 3 lame tests. It would be nice if I give them a bit more attention in the future.

Last commit took care of the tests. Minor changes in the code were required for the tests to run as expected. Came up with 7 tests (and 7 is my favorite number)!

Last words

• The whole project was started and finished in less than 24h (the commit history is available on github). Not deliberately.
• The whole project was coded on a Mid-2009 MacBook Pro 17 (one build took ~40 sec). Again, not deliberately.
• The whole project was coded while listening to Serbian turbo-folk - deliberately. That tends to boost my productivity with at least 20-30%, depending on the song :)
• This is the first project that got me googling and writing unit tests.

Well... that's all, folks. I hope we get to see each other again :)

M.