Wallet Core

A digital wallet microservice built with Go and Clean Architecture. Manages clients, accounts, and fund transfers between accounts using an event-driven approach and the Unit of Work pattern.

Architecture

cmd/                        # Application entrypoint
internal/
  entity/                   # Domain entities (Client, Account, Transaction)
  gateway/                  # Repository interfaces (ports)
  database/                 # MySQL repository implementations (adapters)
  usecase/                  # Application use cases
    createclient/
    createaccount/
    createtransaction/
    mocks/                  # Shared test mocks
  event/                    # Domain events
  web/                      # HTTP handlers
pkg/
  events/                   # Event dispatcher (generic)
  uow/                      # Unit of Work implementation

The project follows Clean Architecture principles: entities at the core with no external dependencies, use cases orchestrating business logic, and gateways as port interfaces implemented by the database layer.

Tech Stack

• Go 1.22 - standard library HTTP server (net/http)
• MySQL 5.7 - persistence
• Docker Compose - local infrastructure
• SQLite - used in integration tests
• testify - test assertions and mocks

Features

• Client registration
• Account creation linked to a client
• Fund transfers between accounts with atomic balance updates (Unit of Work)
• Event dispatching on transaction creation

API Endpoints

All endpoints accept and return JSON.

Method	Path	Description
POST	/clients	Create a new client
POST	/accounts	Create an account for a client
POST	/transactions	Transfer funds between accounts

POST /clients

Request:

{
  "name": "John Doe",
  "email": "john@mail.com"
}

Response (201):

{
  "id": "uuid",
  "name": "John Doe",
  "email": "john@mail.com",
  "createdAt": "2024-01-01T00:00:00Z",
  "updatedAt": "2024-01-01T00:00:00Z"
}

POST /accounts

Request:

{
  "clientId": "client-uuid"
}

Response (201):

{
  "id": "account-uuid"
}

POST /transactions

Request:

{
  "accountFromId": "source-account-uuid",
  "accountToId": "destination-account-uuid",
  "amount": 100
}

Response (201):

{
  "id": "transaction-uuid",
  "accountFromId": "source-account-uuid",
  "accountToId": "destination-account-uuid",
  "amount": 100
}

Getting Started

Prerequisites

• Go 1.22+
• Docker and Docker Compose

Setup

1. Clone the repository:

   git clone https://github.com/marcioecom/wallet-core.git
   cd wallet-core

2. Start MySQL:

   docker compose up -d

   This creates the wallet database and initializes the schema automatically.

3. Install dependencies:

   go mod download

4. Run the application:

   go run cmd/walletcore/main.go

   The server starts on port 8080 by default. Set the PORT environment variable to override (e.g., PORT=:3000).

Running Tests

go test ./...