Pokemons described by Shakespeare. Did get to catcheth those folk all!

My response to a software engineering challenge.

To me, it was quite fun doing this challenge, I hope you'll have a good time looking at it!

Develop a REST API that, given a Pokemon name, returns its Shakespearean description.

• Main
  • Kotlin
  • Spring Boot
• Unit tests
  • JUnit 5
  • Mockito(Kotlin)
• Integration/E2E tests
  • WireMock
  • RestAssured
• Patterns/practices
  • Microservice
  • Hexagonal architecture
  • TDD
• Integrations
  • PokeAPI
  • Shakespeare Translator

You'll need Docker, Java 8 and Maven 3.5+ installed on your favourite OS.

git clone https://github.com/noragami/pokeshake.git
cd pokeshake

mvn clean verify

You can build/run the application packaged as JAR file via Maven and Java...

mvn clean package
java -jar target/pokeshake.jar

... or with Docker (it might take a while to download images the first time):

docker build -t pokeshake/0.0.1 .
docker run -p 8080:8080 pokeshake/0.0.1

curl https://localhost:8080/pokemon/pikachu

{"name":"pikachu","description":"At which hour several of these pokémon gather,  their electricity couldst buildeth and cause lightning storms."}

Shakespeare translator API has a quota limit on the free tier (60 API calls/day, 5 calls/hour). If you reach the quota limit, the API will send an http response code 429 - Too Many Requests. For this reason, I made the decision to forward the same http response code to the client, instead of failing badly with a 500 response code. So we can keep the information and provide the right feedback to the client.

I also implemented a 404 response code if the client requests a Pokemon that doesn't exist.

I encountered a problem during the integration of PokeApi. At first, every call returned a 403 error.

Fun facts:

1. API Documentation didn't help at all
2. The same call worked using the browser

Point 2 made me think that the only difference between the browser call and the console call was the user-agent. By setting up a dummy user-agent, the problem disappeared.

• Document API using OpenAPI/Swagger (using Swagger UI)
• Add a cache layer (all the requests are deterministic, same Pokemon name -> same Pokemon description, same description -> same Shakespeare description)
• We'd need a premium/ultra Shakespeare translator API subscription
• Add Spring Retry policy to automatically re-invoke a failed operation (on the integration side)
• Add a circuit breaker to fail fast if all else fails
• This is a single microservice, but in production you'll want a whole microservices ecosystem to scale the right way such as an api gateway/reverse proxy, a service locator, a config server...