Domain Enhancement

The transactions domain should be enhanced before VSA can be applied.

Some concepts can be added to enhance the Domain Drive Design experience, such as:

• Create Money as a Value Object.
• Use Currency to convert Money to and from USD
• Allow accounts to withdraw values that will make the balance negative (possible overdraft feature can be implemented)
• Produce balance changed domain event for Deposit/Withdraw/Transfer but not for earnings
• Put domain abstractions in another project to be used by another service domain
• Better encapsulation of domain, you must use the aggregate to access any entity

The old application served its purpose. It was a good starting point to create Transactions API and Transactions Domain. I think we can move on and delete these projects from the repository.

Add Observability (Metrics and Traces) using OpenTelemetry to export metrics to Prometheus and traces to Jaeger

We need to add unit tests for the Account Domain.

We're going to add the simplest domain possible, basic CRUD operations on top of the Account, to notify the other domains that we have an account on the app!

Transactions Domain: Add VSA Approach to WebAPI

• Add Commands/Queries
• Add Behaviors
• Configure EF Core and create migrations
• Add EF SecondeLevelCache
• Add integration events/handlers
• Configure events dispatching strategy
• Add endpoints

The Transfer flow should receive another account to perform the In and Out status.

We also need to know the sender and the receiver for all transactions to have a more comprehensive statement.

We need to test the commands!

Adding integration tests!

We need to add logging.

Use OTEL collector to export logs to...?
Use Serilog?
Add Logging Behavior

We need to provide documentation about:

• Vertical Slice Architecture implementation
• Architecture overview of the implementation
• Instructions for running the Banking App
• Microservices Business Rules

TODO

• Criar template de slides
• Criar um detalhamento do summary da palestra, pensando no tempo total da palestra (35min)
• Trazer o código para os slides

Summary

• Apresentação dos palestrantes (Breve introdução sobre nós)
• Introdução ao assunto
  • Contexto (trabalhar em cima do texto de apresentação da palestra)
  • Motivação da palestra (experiência em diversos sistemas utilizando .NET com problemas arquiteturais similares a medida que evoluem)
• Apresentação do problema arquitetural com n-layers
  • Alto acoplamento entre as camadas
  • Classes com mais de uma responsabilidade
  • Dificil manutenabilidade e legibilidade
  • Alta complexibilidade
• Apresentação da solução com vertical slices
  • Conceito
  • Combinação com outras tecnologias de mercado
  • Possível utilização sem as tecnologias de mercado
  • Combinação com outros patterns: CQRS, Event Sourcing, DDD, Transaction Script
  • Prós e Contras
• Tempo reservado para dúvidas

We aren't going to use the react frontend for this presentation. It should be removed.

We need to create a service to handle the fee processing.

For TDC's presentation Authentication and Authorization won't be necessary.

I'll be removing the Azure AD configuration from the API.

We need to create the Taxes domain.
This domain is responsible for applying fees or incomes to the account balance.

It will store:

• AccountId (Guid)
• CurrentBalance (Money)
• LastBalanceChange (DateTime)

Domain Rules:

• Given a configurable time span, if the balance is positive and hasn't changed an income is applied to the account balance.
• Given a configurable time span, if the balance is negative, a fee will be applied to the account for overdraft usage.
• Given a configurable time span, if the balance is zero, nothing happens.

This domain should be notified every time a transaction changes the account balance, except when the balance changes for fees or incomes.