Credit Card aggregator service

An aggregator of multiple credit card provider service, powered by scala 3.

Build Requirements.

• Scala 3 compiler.
• Java Virtual Machine, version 11 or greater.
• Scala Build Tool sbt
• Either one of the following IDE should be fine to navigate the codebase.
  • VSCode with Metals plugin
  • IntelliJ with Scala plugin

Building

This project uses Sbt-native-packager. To build native binary run the following sbt command:

sbt stage

This will generate a local executable binary in ./target/universal/stage/bin/credit-card-aggregator. For other platforms and different formats, see also Creating package

Running

Once you have built the binaries locally, You can launch the app using the following command.

For help:

./target/universal/stage/bin/credit-card-aggregator --help

To run the aggregator service, run the following command:

./target/universal/stage/bin/credit-card-aggregator \
  -p 9090 \
  -c "https://app.clearscore.com/api/global/backend-tech-test/" \
  -s "https://app.clearscore.com/api/global/backend-tech-test/"

Or via start.sh. For example:

export HTTP_PORT=9090
export CSCARDS_ENDPOINT="https://app.clearscore.com/api/global/backend-tech-test/"
export SCOREDCARDS_ENDPOINT="https://app.clearscore.com/api/global/backend-tech-test/"
./start.sh

Note: To shutdown, either press enter or Ctrl-C to halt.

Test

Test can be run with the command: sbt test

Design

I have chosen tapir as so endpoints can be desribed in a declarative way. i.e the credit card endpoint is described as a ServerEndpoint i.e ServerEndpoint[CreditCardRequest, ErrorResponse, CreditCardResponse, Any, F] in CreditCardEndpoint.scala.

This makes the backend agnostic and easy to test endpoint/group of endpoints in an isolated way.

Folder Structure

.
├── README.md
├── build.sbt
├── project
│   ├── build.properties
│   └── plugins.sbt
├── purge-local-build-cache.sh
├── src
│   ├── main
│   │   └── scala
│   │       ├── Main.scala
│   │       ├── app
│   │       │   ├── App.scala
│   │       │   └── Server.scala
│   │       ├── common
│   │       │   └── Scale.scala
│   │       ├── endpoints
│   │       │   ├── CreditCardEndpoint.scala
│   │       │   └── RootEndpoint.scala
│   │       ├── infrastructure
│   │       │   ├── config
│   │       │   │   └── CardProviderConfig.scala
│   │       │   ├── cscards
│   │       │   │   ├── DefaultCsCardProviderConfig.scala
│   │       │   │   └── client
│   │       │   │       ├── CsCardRequest.scala
│   │       │   │       ├── CsCardResponse.scala
│   │       │   │       └── CsCardsClient.scala
│   │       │   └── scoredcards
│   │       │       ├── DefaultScoredCardsProviderConfig.scala
│   │       │       └── client
│   │       │           ├── ScoredCardResponse.scala
│   │       │           ├── ScoredCardsClient.scala
│   │       │           └── ScoredCardsRequest.scala
│   │       ├── model
│   │       │   ├── CreditCard.scala
│   │       │   ├── User.scala
│   │       │   ├── request
│   │       │   │   └── CreditCardRequest.scala
│   │       │   └── response
│   │       │       ├── CreditCardResponse.scala
│   │       │       └── ErrorResponse.scala
│   │       ├── routes
│   │       │   ├── CreditCardRoutes.scala
│   │       │   └── Routes.scala
│   │       ├── service
│   │       │   ├── CreditCardAggregatorService.scala
│   │       │   └── CreditCardPartnerApi.scala
│   │       └── worksheets
│   │           └── DumpDocs.worksheet.sc
│   └── test
│       └── scala
│           ├── app
│           │   └── CreditCardAppIntegrationTest.scala
│           ├── common
│           │   └── ScaleSuite.scala
│           ├── endpoints
│           │   └── CreditCardEndpointsSuite.scala
│           ├── integration
│           │   └── package.scala
│           ├── mocks
│           │   └── package.scala
│           └── service
│               └── CreditCardAggregatorServiceSuite.scala
└── start.sh

Filder/Folder Purpose

File/Folder	Purpose
main/scala/endpoints/CreditCardEndpoint.scala	Definition of /creditcards endpoint with business logic
main/scala/routes	Compose all endpoints to routes
main/scala/model	Models schema and validation logic of server logic
main/scala/service	Domain services i.e CreditCardAggregatorService used by the server
main/scala/infrastructure	Implementations of CreditCardPartnerApi interface
main/scala/app	Composition of services and routes into an HttpApp