nix-ros-overlay VS asdf

I believe this might be due to me also using the ROS overlay for Nix (https://github.com/lopsided98/nix-ros-overlay). Some packages that I'm using from ROS also require PCL, so I suspect that Nix might be ignoring my CUDA-enabled overlay and using the regular PCL package in order to meet the required dependencies. I'm not too sure how to confirm this...

Thanks for the response!

> This is difficult to answer without knowing more details.

The situation specifically is the ROS ecosystem, where metadata is managed in these package.xml files:

https://github.com/ros2/rclcpp/blob/master/rclcpp/package.xm...

The federated nature of the ecosystem has led to a culture where it's very normal to be building dozens of these at once, in the same workspace together, often from multiple repos (the repo above has four in it). So there are several build tools which automate the work of examining a source workspace and building all the packages within it in the correct topological order, respecting build_depend tags. The newest of these tools (colcon) has actually made the package.xml optional in many cases, as it can examine CMakelists, setup.py, BUILD, etc, and discover for itself what the dependencies are.

Your "distribution" of ROS is formed by listing all the packages and repos in this big file, for which there is other tooling to manage pulling dependency sources, whatever: https://github.com/ros/rosdistro/blob/master/foxy/distributi...

Anyway, so the existing ROS/nix efforts (1) seem to basically consume all of this package/distribution metadata at once and generate a giant parallel structure of nix definitions (eg https://github.com/lopsided98/nix-ros-overlay/blob/master/di...), which I fear would be completely opaque to users and any system which required everyone to leave behind these existing workflows would be an immediate non-starter.

I think the ideal scenario (and what it would look like if I built this myself based on debs) would be that you could source the "base" workspace as usual (enter the nix-shell?), and check out source, build packages as usual with colcon, the usual workspace-building tool, but there'd be an extra plugin/verb/flag for it, which would make it build each package as a nix package instead of into the usual installspace. The verb would generate the nix definitions on the fly, and probably handle the invocation and build-parallelism side of it as well.

[1]: https://github.com/acowley/ros2nix, https://github.com/lopsided98/nix-ros-overlay

The main issue most people have with asdf is that it’s annoyingly slow. Not unusably so, but just enough that it’s irritating.

I identified [0] the source for much of it (sub-shells and pipes) and began a PR [1], but became bogged down with BATS testing, and then found mise / rtx, so kind of lost interest. Sorry. You can always implement these if you’d like.

[0]: https://github.com/asdf-vm/asdf/issues/290#issuecomment-1383...

[1]: https://github.com/asdf-vm/asdf/pull/1441

Or if you need to manage more than just node, asdf has been around for over a decade and works great. You can use a .tool-versions to change runtimes for each project you have, in addition to managing your global runtime versions

https://asdf-vm.com/

Why not just use a tool like asdf (https://asdf-vm.com/) or mise (https://mise.jdx.dev/)?

These tools have the advantage of not being multi-taskers and can manage version for all your tools. You wouldn’t need pyenv and npm and rvm and…

We’ve even started committing the .mise.toml files for projects to our repos. That way, since we work on multiple projects that may need multiple versions of the same tool, it’s handled and documented.

The purpose of a version manager is to help you navigate or install any tools for development easily. Version Manager can be one tool for each dependency (e.g. NVM, g) or One tool for all dependencies (e.g. asdf, mise).

(asdf)[https://asdf-vm.com/] fully supports Python and almost any other language. I've been using it for Ruby, Python, Elixir, and other languages for years and never looked back.

Secondly, our development environments must not drift, because then code may behave differently and a change could pass on our machine but fail in production. There are many tools for locking down environments, e.g nix, pkgx, asdf, containers, etc., and they all share the common goal of being able to lock down dependencies for an environment accurately and deterministically. And that needs to be enforced in our local workflow so we don't have to rely on CI environments for correctness. All developers must have environments that are effectively identical to what runs in CI (which itself should be representative of the production environment).

There are many ways this can be done (e.g nix, pkgx, asdf, containers, etc.), and we won’t get into which specific tools to use, because we'll instead cover the essential essence of preventing environment drift:

I've really been enjoying asdf, which is a program that allows you to install specified versions of dev utilities as well as dynamically manage them via shims and .tool-versions files.