bundlers VS nix2container

- the caching works across branches, so for example merging a feature branch to master, if nothing changes the build on master will be very quick

I created something similar to nix-cache for gitlab, but I had to create a dedicated runner running NixOS.

If I could use NixOS for deployment, at that point I would just point the same binary cache to the machine and use the same derivation to build the app. Because the app was already build by CI, it would just download the compiled version. No need for artifactory or similar. In that scenario (you using poetry) you probably would just use poetry2nix to generate the application.

If the OS is not NixOS, but you still want to deploy via nix, then IMO this[2] looks interesting, basically it packages everything in self extracting archive. That you can extract and then run the app.

Other alternatives are these bundlers[3], which includes building toArx (works in a way similar to the previous one but pretends everything is in a single file), RPM, DEB, docker (you would have more control over it if you would use the code directly instead of a bundler though)

And the last option (probably the most obvious one) is that you can simply just use the tool to build the package. Since you're using poetry, then you can generate a wheel from it.

[1] https://github.com/takeda/nix-cde/blob/master/contrib/gitlab...

[2] https://github.com/Ninlives/relocatable.nix

[3] https://github.com/NixOS/bundlers/blob/master/flake.nix

We've seen the opposite. New package managers are built with a much better understanding of the problem space because of Nix and sometimes explicitly taking ideas and concepts. This results in those new systems being far more compatible and easily integrated with Nix itself. Consider the iteration towards better and better locking in python + Node. Consider Rust/Cargo.

There has also been sharing of ideas and collaboration between things us and bazel/buck/spack/etc. I think it is clear that we are all moving towards a similar end state, that often looks very much like Nix, or a re-invention of it.

For things like OCI, Nix predates it, but we should start to re-use the standard. The Tvix group is exploring this and I'd suspect our sandboxing will be OCI at some point. For outputs; we make it easy to convert a Nix package into an equivalent container. Things like flatpack,AppImage,Snap should also be easy for people to output (i'm trying to collect these "transformers"/"bundlers" here: https://github.com/NixOS/bundlers).

Nix 3 has a dead simple, builtin CLI frontend for built packages: https://nixos.org/manual/nix/unstable/command-ref/new-cli/ni...

It uses dockerTools: https://github.com/NixOS/bundlers/blob/master/flake.nix

maybe a bundler can be added that uses OCI tools, thus providing such a wrapper and giving a nice CLI for it

No discussion about Nix-built containers is complete with nix2container:

https://github.com/nlewo/nix2container

It is truly magical for handling large, multi-layered containers. Instead of building the container archives themselves and storing them in the nix store, it builds a JSON manifest that is consumed by a lightly patched version of skopeo that streams the layers directly to either your local container engine or the registry.

This means you never rebuild or reupload a container layer that is unchanged.

- Container images are built with https://github.com/nlewo/nix2container instead of Nix's built-in docker tools, because nix2container allows configuration of layers and thus makes it easier to share layers between images and improve layer caching.

As for integrating it into our CI pipeline, this is pretty much CI system agnostic as all you have to do is run `nix build ...` inside the pipeline, generating a `result` directory or file as an artifact that, in the case of nix2container, can be pushed to your container image registry.

dockerTools is the canonical way, but https://github.com/nlewo/nix2container seems to be gaining support as it's faster and doesn't use so much disk space while building.

> The key factor behind our decision was the realization that while Docker images are industry standard, moving around 100s of megabytes of images seems unnecessarily heavy-handed when we just need to synchronize a small change.

I think the culprit is more the GitHub Actions cache than Docker since it seems to be hard to get a clean cache management. I'm not sure about caching Docker image layers, but caching the Nix store with GitHub Actions is pretty complicated (not even sure it's possible): this means we have to download all required Nix store paths on each run, but i consider this is because of a GitHub Action cache limitation.

So, did you consider using another CI, which offers better caching mechanisms?

With a CI able to preserve the Nix store (Hydra[1] or Hercules[2] for instance), I think nix2container (author here) could also fit almost all of your requirements ("composability", reproducibility, isolation) and maybe provide better performances because it is able to split your application into several layers [2][3].

Note i'm pretty sure a lot of Docker CI also allows to efficiently build Docker images.

[1] https://hercules-ci.com/

[2] https://grahamc.com/blog/nix-and-layered-docker-images

[3] https://github.com/nlewo/nix2container/blob/85670cab354f7df6...

FYI, the nix2container [1] project (author here) aims to speedup the standard Nix container workflow (dockerTools.buildImage) by basically skipping the tarball step: it directly streams non already pushed layers.

[1] https://github.com/nlewo/nix2container

To get Rust incremental builds, did you consider using something such as crane https://github.com/ipetkov/crane ?

And regarding OCI images, i built nix2container (https://github.com/nlewo/nix2container) to speed up image build and push times.

For a more modern iteration of that idea, check out https://github.com/nlewo/nix2container

It has all the benefits of OP but produces the images much faster, and with less on-disk usage.

I've been using nix2container[1] for awhile now. It looks like this depends on Docker, have you guys considered removing that dependency? It shouldn't be necessary to create an OCI compliant image with Nix.

[1]: https://github.com/nlewo/nix2container

With https://github.com/nlewo/nix2container, I'm trying to make a more standalone tool. Basically, a Go binary takes a reference graph and produces a JSON file describing a container image. This JSON file is then ingested by a Skopeo fork (it adds a new `transport`) to produce images (to file, registries,...).

Currently, it supports the dockerTools layering algorithm and is designed to work with Guix [1] as well;)

[1] https://github.com/nlewo/nix2container/blob/065e5b108650ee4c...