/clearscore-creditcards

Primary LanguageScala

ClearScore Credit Card service

Table of Contents

Build

To prepare the service for deploy/run execute the following:

$ git clone https://github.com/thenobody/clearscore-creditcards.git
$ cd clearscore-creditcards
$ sbt universal:packageBin

After finishing, a self-contained zip archive will become available at:

credit-cards-service/target/universal/credit-cards-service-0.0.1.zip

Tests

To run the unit tests for both submodules run

$ sbt test

Running

The service can be run after unpacking the zip file mentioned in section Build.

$ unzip credit-cards-service/target/universal/credit-cards-service-0.0.1.zip
$ credit-cards-service-0.0.1/bin/credit-cards-service

The service is ready to receive request after the following is printed into the console:

00:39:30.889 [default-akka.actor.default-dispatcher-5] INFO  n.t.c.creditcards.service.Main$ - Server successfully started on /0:0:0:0:0:0:0:0:8080

Configuration

The service uses Lightbend Config and as such can be configured externally either by:

1. ENV variables

Some paramaters are overridable directly, namely:

  • HTTP_INTEFACE - host to which the service binds, default 0.0.0.0
  • HTTP_PORT - port to which the service binds, default 8080
  • CSCARDS_ENDPOINT - the base endpoint of CSCards API, default https://y4xvbk1ki5.execute-api.us-west-2.amazonaws.com/CS
  • SCOREDCARDS_ENDPOINT - the base endpoint of CSCards API, default https://m33dnjs979.execute-api.us-west-2.amazonaws.com/CS

To override any of these, simply provide ENV variables when starting the service, e.g.

$ HTTP_PORT=8081 ./credit-cards-service-0.0.1/bin/credit-cards-service

2. Config file

An external application.conf file can be supplied via

./credit-cards-service-0.0.1/bin/credit-cards-service \
  -Dconfig.file=/path/to/application.conf

The structure of the external configuration file should follow format of application.conf

Implementation notes

The service follows the assignment requiremets specified in the PDF document. The HTTP service is implemented as a akka-http application with basic usage of cats.

The implementation consists for two SBT submodules:

credit-cards-core

The submodule contains model classes, client and service implementations for both credit card providers (CSCards and ScoredCards) as well as unit tests.

The structure of submodule follows the separation between CSCards-related logic and ScoredCards-related logic. Packges net.thenobody.clearscore.creditcards.core.model.cscards and net.thenobody.clearscore.creditcards.core.model.scoredcards contain entity classes representing the responses from their respective APIs.

Note: I've originally attempted to use the classes generated by swagger-codegen. However, this even after a substantial effort wasn't feasible as the swagger-generated code depends on spray-http which prevents akka to operate normally. As such, I've opted to extract the generated model classes into these packages and skip generating swagger-code.

Client classes are similarly split across in net.thenobody.clearscore.creditcards.core.service.cscards and net.thenobody.clearscore.creditcards.core.service.scoredcards.

Additionally, collecting the API responses is abstracted into CardsService and implementations. These are subsequently used in the main service.

credit-cards-service

The HTTP service logic is defined here as a akka-http service with two HTTP endpoints (defined in RootRoute)

/creditcards - expects POST requests as specified in the swagger json Microservice-swagger.json. The endpoint responds with

  • HTTP 200 on valid input
  • HTTP 400 if the request body does not follow the required schema coupled with a { "error": ... } message
  • HTTP 500 if there was an error reading from one or more external APIs (or other issues)

/ping - alwasys responds with HTTP 200 and body pond