Packsnap

Packsnap is a reproducible Docker image builder implemented in pure Nix, heavily inspired by Nixpacks.

Installation

To install it, just add it to your project’s Flake inputs:

{
  # ...
  inputs.packsnap.url = "github:aleksrutins/packsnap";
  # ...
}

Basic Usage

To build a basic app using one of the supported languages, put a simple flake.nix in your project’s root:

{
  description = "My fantastic new containerized project";

  inputs.packsnap.url = "https://flakehub.com/f/aleksrutins/packsnap/*.tar.gz";
  inputs.flake-utils.url = "github:numtide/flake-utils";

  outputs = { self, nixpkgs, flake-utils, packsnap }: flake-utils.lib.eachDefaultSystem (system: {
      packages.container = packsnap.lib.${system}.build { name = "my-image"; path = ./.; };
  });
}

Now, you can build it with nix build .#container, and then load it into Docker (or Podman) with docker load < result.

Note: Unfortunately, at least at the moment, this image will only work if built on Linux.

For a custom plan, replace build with buildCustomPlan.