The entry project for the Catalogue and the Subscription service is the Api project.

Catalogue Service

• Folder to be in : Assessment.Catalogue.Api
• On your command window : dotnet run
• To view swagger : http://localhost:5015/swagger/index.html

For Subscription Service

• folder to be in : Assessment.Subscription.Api
• command to run : dotnet run
• swagger url : http://localhost:5020/swagger/index.html

Identity server

• in the root folder of the service run : dotnet run
• To register a new user : http://localhost:5010/

Api Gateway

• in the root folder of the service run : dotnet run
• The Api Gateway runs from :http://localhost:5005

I followed a microservice type of architecture resulting in 4 services.

• Assessment.Catalogue: This is an internal service, to be hosted behind a firewall. It holds the details of the books.
• Assessment.Subscription: This is an internal service, to be hosted behind a firewall and it caters to when the user wants to subscribe or unsubscribe.
• Assessment.gateway : This is how the outside world can talk to our internal service. It checks if the user has been authenticated before letting them proceed.
• Assessment.identityserver4 : This caters for all our authentication needs.

• I made use of DDD, which has the benefit of having all your logic sit in one place rather than scatted throughout your system.

• I also made use of CQRS, the repository pattern, and the Unit of Work.

For our IdentityServer, I made use of IdentityServer4 and for the ApiGateWay, I made use of Ocelot. Also in the folder placed a high-level overview of how the system is laid out.

• The subscription services goes and queries the catalogue, when a new subscription is made, Which can impact the user experience if the catalogue service goes down during the process.
• In future we can improve the design by making use of a queue as well as event sourcing, to trigger an event which says am now waiting for the book name since I now have the bookId, which will result in eventual consistency but a better user experience in case the Catalogue service goes down during the process.