flowchart-builder

A python script to create a simple flowchart from data in a yml file

📊 YAML Flowchart Generator (Graphviz)

A lightweight Python utility that converts a simple YAML-defined workflow into a visual flowchart using Graphviz.

It generates:

• 🖼️ A PNG flowchart image
• 🌐 A simple HTML viewer to display the diagram

🚀 Features

• Define workflows in simple YAML format
• Supports:
  • Linear steps
  • Decision nodes (yes/no)
  • Automatically generates flowcharts using Graphviz
• Outputs:
• flowchart.png
• viewer.html (static page to display diagram)
• Minimal setup, no web framework required

📦 Requirements

• Python dependencies
• pip install pyyaml graphviz
• System dependency (required)

Graphviz must be installed on your system:

Ubuntu / WSL

• sudo apt install graphviz

Mac (Homebrew)

• brew install graphviz

Windows

Download installer: https://graphviz.org/download/

Add Graphviz bin folder to PATH.

📁 Project Structure

. ├── flow.yml ├── generate.py ├── flowchart.png (auto-generated) └── viewer.html (static viewer)

🧾 YAML Format

Define your workflow like this:

start: Start steps:

• id: step1 text: Load data next: step2

• id: step2 text: Validate data decision: true yes: step3 no: step4

• id: step3 text: Process data next: step5

• id: step4 text: Reject data next: end

• id: step5 text: Save results next: end

end: End

▶️ Usage

Run the generator:

python script.py

This will generate:

flowchart.png

🌐 View Flowchart

Open the HTML file in your browser:

open viewer.html   # Mac
start viewer.html  # Windows
xdg-open viewer.html # Linux

🧠 How it works

• YAML is parsed into a structured workflow
• Graph nodes are created using Graphviz
• Edges are generated based on:
  • next
  • yes / no (for decisions)
• Output is rendered as a PNG image
• HTML file simply embeds the image

📌 Example Output

Start ↓ Load Data ↓ Validate Data ↙ ↘ Reject Process ↓ ↓ End Save ↓ End

⚡ Why this tool?

• No UI framework required
• No complex diagramming tools

Ideal for:

• Documentation
• Workflow visualization
• LMS / training content
• Architecture drafts
• Quick prototyping

🔧 Future Improvements

• SVG output support (sharper diagrams)
• Interactive HTML flowcharts
• Swimlane support
• Auto layout optimization
• CLI wrapper (flowgen generate flow.yml)

📄 License

MIT — feel free to use and modify.