NixoScope

Why This Tool Exists

I recently switched to the dendritic design pattern with flake parts and needed a way to understand my module structure:

• Which modules get imported from other modules?
• Which modules get declared in what files?

Manually tracing these relationships through code was tedious and error-prone, so I built this tool to visualize the module dependency graph.

How It Works

This tool leverages the new .graph output introduced in the Nixpkgs module system. Thanks to this merged PR, we can now obtain a JSON representing the tree of modules that took part in the evaluation of a configuration.

For more details, see the announcement on NixOS Discourse.

Usage

Tip

You can also use nix run github:giomf/nixoscope instead of cloning this repository and executing nixoscope.py

Obtaining the input graph:

nix eval --json '.#nixosConfigurations.<your-config>.graph' > graph.json

Read the input graph:

nixoscope.py --input graph.json
default: graph.json

Output format:

Graphviz:

nixoscope.py --format gv
default: gv

JSON

nixoscope.py --format json
default: gv

Filter by option prefix

nixoscope.py --option "flake.modules"

Result

Filtered by "flake.modules"

Disclaimer

This project uses AI as an aid.