Hydra Viewer

Hydra Viewer is a terminal-based developer tool designed to eliminate the friction of managing complex Hydra configurations. It provides a real-time, interactive environment to visualize, edit, and verify your configuration hierarchy without leaving the terminal.

Built with Textual, it combines a modern TUI experience with the flexibility of Hydra's configuration system.

🌟 Key Features

🏢 Real-Time Merge Preview

Instantly see the fully resolved configuration. As you edit files or type overrides, Hydra Viewer merges your defaults list and displays the final result on the right panel. No more running your app just to check if your overrides worked!

📝 Hybrid Editing Modes

• Multi-Panel Mode: Perfect for initial setup. Each file in your defaults list is displayed as a separate panel, allowing you to see the entire configuration flow at once.
• Tabbed Mode: Ideal for focused editing of individual modules.
• Auto-Save & Hot-Reload: Changes are automatically saved (with a 500ms debounce) and the preview is updated instantly.

🧭 Advanced Navigation

• Module Tree: A logical view of your Hydra configuration structure. Double-click a node to update your defaults entry directly from the tree!
• File Browser: A full-featured file manager with hot-keys for creating, renaming, moving, and deleting YAML files.
• Auto-detect: Launching in a project root automatically finds your entry-point config.yaml or conf/ directory.

🧪 Dynamic Overrides

The bottom command bar supports full Hydra override syntax (e.g., model.layers=50 ++db.port=3306). The resolved view updates live as you type, helping you debug complex CLI arguments before execution.

📸 Configuration Snapshots

Experiment without fear. Create full snapshots of your configuration state and restore them later. perfect for comparing different experimental setups.

🚀 Installation

Using pip

pip install hydra-viewer

Using uv (Recommended)

If you use uv, you can run it as a tool:

uv tool install hydra-viewer

Or run it instantly without installation:

uvx hydra-viewer

📖 Deep Dive & Workflow

1. Launching

Navigate to your project root (where config.yaml or a conf/ folder resides):

hydra-viewer

If you are elsewhere, specify the path:

hydra-viewer /path/to/my/hydra/project

2. Editing Workflow

• Use the left panel to browse files.
• Press Ctrl+E to toggle between Multi-Panel and Tab modes.
• Edits in the center panel are synced to disk automatically. The right panel (Resolved View) will turn red if your YAML syntax or Hydra defaults are invalid.

3. Testing Overrides

Type your intended CLI arguments in the bottom command bar.

• model=resnet50 (Change group)
• db.timeout=10 (Override value)
• ++new_param=true (Add new parameter)

4. Managing Snapshots

• Ctrl+B: Tag the current state of all config files.
• Ctrl+R: View and restore from your history.

⌨️ Keyboard Shortcuts

🛠 Troubleshooting

1. "No config directory found": Ensure you are in the directory containing config.yaml or use the command line argument.
2. Preview is Red: This indicates a validation error. Check the error message at the top of the preview pane for details on which line in which file is causing the issue.
3. Symbols appear as squares: Since this tool is built with Textual and uses certain symbols, you might see square boxes (tofu) if your terminal environment does not have Nerd Fonts installed. This is purely aesthetic and does not affect the tool's functionality.
4. Snapshots: Snapshots are stored in a hidden .hydra_backups/ directory.

📄 License

This project is licensed under the MIT License - see the file for details.