ChatGPT Microservice (TypeScript, Clean Architecture)

This project is a microservice for chat completions using the OpenAI API, following Clean Architecture principles. It stores chat sessions and messages in PostgreSQL and exposes a REST API for creating and continuing chats.

---

Features

• Create new chat sessions or continue existing ones
• Stores chat and message history in PostgreSQL
• Clean, testable architecture
• 100% code coverage in tests

---

Getting Started

Prerequisites

• Node.js (v18+ recommended)
• Docker & Docker Compose
• OpenAI API key

---

1. Clone the Repository

git clone https://github.com/yourusername/chatgpt-microservice-ts.git
cd chatgpt-microservice-ts

---

2. Configure Environment Variables

Copy .env.example to .env and fill in your values:

OPENAI_API_KEY=your-openai-api-key
...

---

3. Start PostgreSQL with Docker Compose

docker compose up -d --build

This will start a PostgreSQL 15 container and initialize the schema.

---

4. Install Dependencies

npm install

---

5. Run the Service

npm run start

The API will be available at http://localhost:SERVER_PORT.

---

API Usage

POST api/chat/completion

Create a new chat or continue an existing one.

Request Body

{
  "chatId": "optional-chat-id",      // Omit or set to continue a chat
  "userId": "user-uuid",
  "userMessage": "Hello, how are you?",
  "config": {
    "model": "gpt-3.5-turbo",
    "max_tokens": 100,
    "temperature": 0.7,
    "stop": ["super-end"]
  }
}

• chatId: Omit to start a new chat, or provide to continue an existing chat.
• userId: Your user identifier.
• userMessage: The message to send.
• config: (Optional) Chat configuration (model, tokens, etc.).

Response

{
  "chatId": "uuid-of-chat",
  "messages": [
    { "role": "system", "content": "..." },
    { "role": "user", "content": "Hello, how are you?" },
    { "role": "assistant", "content": "I'm fine, thank you!" }
  ]
}

• chatId: Use this for subsequent requests to continue the conversation.
• messages: Full chat history.

---

Example: Continue a Chat

1. Start a new chat (omit chatId).
2. Use the returned chatId for the next message.

---

Running Tests

npm test

---

Project Structure

• src/domain — Entities, models, use cases, repository interfaces
• src/infra — DB, API adapters, migrations
• src/main — Server setup, routes, configs
• src/presentation — Controllers, http handling

---

Troubleshooting

• If you get relation "chats" does not exist, ensure your migrations ran. Try:

  docker compose down -v
  docker compose up -d --build

• Ensure your .env values are valid JSON where required (e.g., STOP).
• If you see a deprecation warning related to punycode there is nothing to do. It is a problem for the openainpm package and its dependencies (specifically the dependency tr46 which uses the deprecated punycode module).

---

Authors

• Michael Dias - mikaws

---

License

MIT