An implementation of the java pet store using FP techniques in scala.
I have stood up a few endpoints, with something like tagless final services and repositories. Repositories developed in Doobie.
Updated to the latest of all of the things as I begin to abstract away the effect type.
I am still exploring tagless final and how to fit all of the pieces together. Hoping to get into a more complete functional example, as well as a UI and some business rules / validations.
I could use some help with Scalacheck and a UI if people feel compelled to jump in.
Also, if you have general feedback on how things could be better, feel free to post an issue / gist or open a PR!
The goal for this project is to demonstrate how to build an application using FP techniques in Scala. When starting out in Scala coming from a Java background, it was extremely difficult to piece together all of the little bits in order to make a cohesive whole application.
As the goal of the project is to help Java / Spring folks understand how to build an application in Scala, I will not be looking to employ the more esoteric features in Scala like Type Classes and Category Theory. Those things will be present, but I hope to obscure them in parts the purpose of allowing the reader to understand what is going on in the code.
I will reach out to Java developers along the way, to see if techniques that I use are too confusing, or have a low enough barrier to entry to pick up quickly.
I am going to work with the TypeLevel stack initially and see how far I can go with it. I believe that framing the concepts in code in an easy to understand way should be possible with Typelevel.
- HTTP4S as the web server. I could have gone with finch, twitter server, or akka-http here as well, but I have been interested in learning http4s.
- Circe for json serialization.
- Tagless Final for my core domain.
- Doobie for database access
Start up sbt:
> sbt
Once sbt has loaded, you can start up the application
> ~re-start
This uses revolver, which is a great way to develop and test the application. Doing things this way the application will be automatically rebuilt when you make code changes
To stop the app in sbt, hit the Enter key and then type:
> re-stop
Building out a test suite using Python. The reason is that typically we want to run tests against a live environment when we deploy our code in order to make sure that everything is running properly in the target environment. It is reassuring to know that your code works across clients.
In order to run the functional tests, your machine will need to have Python 2.7 and pip, and virtualenv.
- To install pip on a Mac, run
sudo easy_install pip - Then install virutalenv
sudo pip install virtualenv
To test out the app, first start it up following the directions above and doing re-start
Then, in a separate terminal, run the test suite:
> cd functional_test
> ./run.py live_tests -v