comfyui-node-adder

name	comfyui-node-adder
description	Adds new custom nodes to the ComfyUI Nix project, including npins fetching, dependency resolution in package.nix, disabling impure pip installs, and verifying the Nix build.

ComfyUI Node Adder

This skill provides the procedural workflow for adding new ComfyUI custom nodes from GitHub or GitLab to this Nixified project.

Workflow

1. Add the Node to npins:

   • Run the script via Nix: nix run .#legacyPackages.x86_64-linux.nixified-ai.internal.add-comfyui-node -- <repository_url>
   • This script generates a sanitized lowercase node name (e.g., comfyui-node-name) and updates flake-modules/projects/comfyui/customNodes-npins/sources.json.

2. Analyze Dependencies:

   • Check the target repository for a requirements.txt or pyproject.toml.
   • Identify required Python packages.

3. Check Nixpkgs Availability:

   • Check if dependencies exist in Nix using: nix build .#comfyui-nvidia.passthru.python3Packages.<package_name>.pname --raw

4. Create package.nix (if needed):

   • Create flake-modules/projects/comfyui/customNodes/<sanitized-node-name>/package.nix.
   • Do not set pname or version. These are automatically generated from the npin source data by the nodePropsFromNpinSource function in flake-modules/projects/comfyui/lib.nix.
   • Return an attrset of overrides (e.g. { propagatedBuildInputs = [ ... ]; }).
   • Include dependencies in propagatedBuildInputs.
   • Note: If there are no dependencies and no impure installation scripts, a package.nix is generally not needed.

5. Disable Impure Auto-Install Logic:

   • Crucial: Many ComfyUI nodes attempt to run pip install or apt-get at runtime (e.g., in __init__.py). This will crash in a Nix environment.
   • Patch these out using postPatch in the package.nix:

     postPatch = ''
       # Safely replace function calls without breaking function definitions
       # Example: replacing `install_requirements()` with `pass` only when it's called
       sed -i -e 's/^\s*install_requirements().*/pass/g' __init__.py
       
       # Or, if a function is DEFINED in the file, make it return early:
       sed -i -e 's/def install_requirements():/def install_requirements():\n    return/g' __init__.py
     '';
     

   • Export any environment variables that skip auto-installs (e.g., env.DISABLE_TENSORRT_AUTO_INSTALL = "true";).

6. Fix Inherited Build Tools (ninja):

   • If the node inherits native build tools (like ninja or cmake) from dependencies, the Nix buildPhase may incorrectly attempt to compile it and fail with ninja: error: loading 'build.ninja'.
   • To bypass this, add to package.nix:

     dontBuild = true;
     dontConfigure = true;
     

7. Verify the Build:

   • Test the custom node derivation: nix build .#comfyui-nvidia.passthru.comfyuiCustomNodes.<sanitized-node-name> -L --no-link

8. Format Code:

   • Run nix fmt in the workspace root to format the newly created and modified files.

9. Commit:

   • Stage the changes to sources.json and the newly created package.nix files.
   • Commit the changes with an appropriate message.