Install .NET packages on NixOS from GitHub

Overview

This guide shows how to build a .NET package from GitHub source. The project used to illustrate the process can be found on GitHub.

Create derivation

The first thing you'll want to do is create a derivation for your package.

Create a file for your package. In this case, I called mine fitch.nix.

Since I'm building a .NET package from the GitHub source, I use buildDotnetModule, dotnetCorePackages, and fetchFromGithub.

To get the rev, use the git log command. It's the hash of the latest commit.

Fake SHA

{
  fetchFromGitHub,
  buildDotnetModule,
  dotnetCorePackages
}:

buildDotnetModule {
  name = "fitch";

  src = fetchFromGitHub {
    owner = "lqdev";
    repo = "fitch";
    rev = "e5fb91ddf57eb5611e0e313af29126e590cd149f";
    sha256 = "";
  };

  projectFile = "src/fitch.fsproj";
  executables = "fitch";
  dotnet-sdk = dotnetCorePackages.sdk_8_0;
  dotnet-runtime = dotnetCorePackages.runtime_8_0;
  nugetDeps = ./deps.nix;
}

At this point the sha256 will be empty because you'll get it later in the process.

Create default.nix

let
  pkgs = import <nixpkgs> { };
in
{
  fitch = pkgs.callPackage ./fitch.nix { };
}

Fetch dependencies

Create a file called deps.nix. This will contain the dependencies you need for your application.

touch deps.nix

Then, run nix-build -A fitch.fetch-deps. This should fail because of the empty SHA.

Update SHA

The empty SHA will fail. However, the error message will contain the actual SHA value. Copy that and paste it into the sha256 property.

{
  lib    
  fetchFromGitHub,
  buildDotnetModule,
  dotnetCorePackages
}:

buildDotnetModule {
  name = "fitch";

  src = fetchFromGitHub {
    owner = "lqdev";
    repo = "fitch";
    rev = "e5fb91ddf57eb5611e0e313af29126e590cd149f";
    sha256 = "74xddAUGQNVliVs5o3zQQEAUAoF9r8iBmiiBr4qrUgw=";
  };

  projectFile = "src/fitch.fsproj";
  executables = "fitch";
  dotnet-sdk = dotnetCorePackages.sdk_7_0;
  dotnet-runtime = dotnetCorePackages.runtime_7_0;
  nugetDeps = ./deps.nix;
}

Get dependencies

Now that you have the correct SHA, try getting the dependencies again. These dependencies are created in a series of steps:

Run the following command sudo nix-build -A fitch.fetch-deps. The result of this command is an executable script called result.
Run the result script. sudo ./result deps.nix. This will generate the lockfile called deps.nix and is referenced by the nugetDeps property.

Build package

Once everything is set up, run nix-build -A fitch. This will package and install the package onto your system.

Add to configuration

To add the newly built package to your configuration.nix, add it to your packages:

environment.systemPackages = with pkgs; [
    #...
    (callPackage ./fitch.nix {})
    #...
];

Then, run nixos-rebuild switch. This should now install the package onto your PC.

(Optional) Initialize when shell starts

In my case, since I want fitch to run when the terminal starts, I edit my bash configuration in the configuration.nix file.

programs.bash = {
    interactiveShellInit = "fitch";
}