FastAPI DAG Checker (flowcraft-api)

📌 Project Overview

This is a FastAPI-based backend that provides an API to check if a directed graph is a Directed Acyclic Graph (DAG). It is designed to work with the Flowcraft frontend, which submits a pipeline to determine whether the graph is a DAG.

🚀 Features

• Parses and analyzes graph structures submitted via API
• Uses Kahn’s Algorithm to determine if the graph is a DAG
• Provides CORS support for frontend integration
• Fast and efficient processing using FastAPI

🏗️ Project Architecture

backend/
├── main.py               # FastAPI application
├── requirements.txt      # Python dependencies
├── README.md             # Project documentation

⚙️ Installation and Setup

To run this project locally, follow these steps:

1. Clone the repository:

   git clone <repository-url>
   cd backend

2. Create a virtual environment and activate it:

   python -m venv venv
   source venv/bin/activate  # On Windows: venv\Scripts\activate

3. Install dependencies:

   pip install -r requirements.txt

4. Run the FastAPI server:

   uvicorn main:app --reload

The API will be available at http://127.0.0.1:8000/.

📡 API Endpoints

Health Check

• Endpoint: /
• Method: GET
• Response: { "Ping": "Pong" }

Parse Pipeline

• Endpoint: /pipelines/parse

• Method: POST

• Request Body:

  {
    "nodes": [{ "id": "A" }, { "id": "B" }, { "id": "C" }],
    "edges": [
      { "source": "A", "target": "B" },
      { "source": "B", "target": "C" }
    ]
  }

• Response:

  {
    "num_nodes": 3,
    "num_edges": 2,
    "is_dag": true
  }

🛠️ Dependencies

• fastapi - Web framework for Python
• uvicorn - ASGI server to run FastAPI apps

🛡️ CORS Configuration

The backend supports CORS to allow requests from the frontend:

app.add_middleware(
    CORSMiddleware,
    allow_origins=["http://localhost:3000"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

🔗 Integration with Flowcraft

This backend is designed to work seamlessly with the Flowcraft frontend, which allows users to visually create and submit pipeline graphs for validation.

📜 License

This project is open-source and available under the MIT License.

---

Feel free to contribute, report issues, or suggest improvements!

Happy coding! 🚀