Introduction to Nix Output Monitor (NOM)
Nix Output Monitor, commonly known as "nom," is a tool that enhances the output of your Nix builds. It's designed to provide additional information and insights during the build process, making it easier to understand what's happening under the hood as you work with Nix.
Features and Functionality
Colored Build Status: While your build runs, nom provides a colorful interface at the bottom of your build log. This interface displays various stages of your build, such as running builds, completed tasks, and planned steps, using intuitive symbols and colors that make it easy to track progress at a glance.
Symbols and Colors Legend:
⏵(yellow): Running builds✔(green): Completed builds⏳︎︎︎(blue): Planned builds⚠(red): Failed builds↓ ⏵/↑ ⏵(yellow): Running downloads/uploads↓ ✔/↑ ✔(green): Completed downloads/uploads
Dependency Graph: Nom presents a simplified visualization of your build's dependency graph, focusing on the most relevant dependencies, and uses color to convey status.
Usage and Integration
Nom seamlessly integrates with Nix commands, acting as a drop-in replacement for commands like nix-build, nix shell, and nix develop. With its flexible interface, users can choose between JSON-based outputs for detailed information or a more traditional log parsing approach for human-readable logs.
Installation
Installing nom is straightforward:
- nixpkgs: Available in nixpkgs, it can be easily installed via
pkgs.nix-output-monitor. - Cabal: Clone the repository and use
cabal installto set it up. - Nix: It can also be installed using
nix buildornix-env.
To ensure you have the latest version, consider installing from the nixos-unstable branch.
Limitations and Considerations
While nom offers a wealth of information, there are a few caveats:
- The tool may not display remote builds accurately if they're pending uploads or downloads.
- The dependency graph might not fully populate under certain conditions.
- Assumptions like expecting the Nix store to be located at "/nix/store" can lead to quirks on some setups.
Nom is continually evolving, and users are encouraged to contribute feedback or improvements via GitHub. Despite its limitations, nom is a valuable resource for developers looking to gain deeper insight into their Nix build processes, providing clarity and enhancing productivity.