🐬 Building event-driven systems with Kafka and ElysiaJS

⚠️ This repository was created with the idea to practice using Kafka.

Problem

Every time a financial transaction is created it must be validated by our anti-fraud microservice and then the same service sends a message back to update the transaction status. For now, we have only three transaction statuses:

• pending
• approved
• rejected

Every transaction with a value greater than 1000 should be rejected.

Technologies Used

• Bun: A fast JavaScript runtime that is used for running the anti-fraud and transaction services.
• Elysia: A framework used for building the application's web services.
• Apache Kafka: The event streaming platform used to handle messaging between services.
• Drizzle: An ORM (Object-Relational Mapping) tool used for interacting with the database.
• PostgreSQL: The relational database used for storing transaction data.

How to run

Pre-requisites

To be able to start development the application make sure that you have the following pre-requisites installed:

• Bun

  curl -fsSL https://bun.sh/install | bash

• Docker and Docker Compose installed
• K6 (optional)

---

Running the app

To be able to start development the application make sure that you have the following pre-requisites installed:

1. Clone repository:

   git clone https://github.com/vsantos1711/elysia-transaction-validate.git && cd elysia-transaction-validate

2. Start the Kafka using Docker Compose:

   docker compose up

3. Run the anti-fraud service:

   cd anti-fraud && bun install && bun run dev

4. Run the transaction service:

   cd transaction && bun install && bun run dev

API Endpoint

Create Transaction

• URL: /transaction

• Method: POST

• Request Body:

  {
    "accountExternalIdDebit": "string",
    "accountExternalIdCredit": "string",
    "tranferTypeId": 1,
    "value": 1
  }

Run k6 test

k6 run scripts/k6.js