Example Node.js Project Nix Flake

Flake is set up as a fixed output derivation. This means we can do impure things like access the internet (for NPM to work) as long as we lock down the output hash. Because NPM has a lock file it should be determistic.

This is mostly a learning exercise to help me master the Nix programming language.

Building

nix build

Developing

nix develop

Add as systemd service

Add the following to configuration.nix to always run in the background:

  # Add the flake as an input
  nixpkgs.overlays = [
    (final: prev: {
      nodeNix = (builtins.getFlake (toString /home/cjdell/Projects/node-nix)).packages.${pkgs.system}.default;
    })
  ];

  # Define the systemd service
  systemd.services.node-nix = {
    description = "Node Nix Service";
    after = [ "network.target" ];

    # Ensure the service is started at boot
    wantedBy = [ "multi-user.target" ];

    # Run the output of the flake with the Node.js binary
    serviceConfig = {
      ExecStart = "${pkgs.nodejs}/bin/node ${pkgs.nodeNix}/lib/out/main.mjs";
      Restart = "always";
      Environment = "NODE_ENV=production";
    };
  };

  # Enable the service
  systemd.services.node-nix-service.enable = true;

Verify it is running with:

sudo journalctl -u node-nix -f