How would you compare Earthly to creating Docker images using Nix[0]? I love Nix declarative nature with strong emphasis on reproducibility.
[0]: https://nixos.org/guides/building-and-running-docker-images....
[0]: https://nixos.org/guides/building-and-running-docker-images....
The caching and our future plans for distributed builds have some similarities with Nix Hydra and Bazel but creating images in earthly is closer to docker multistage builds than it is to nix.
We are not just for building docker images, though. In the real world a 'build' is more than just building an image. It will have linting, and tests and integration tests and maybe some services need to be stood up and tore down in between to make sure an api contract wasn't broken and you might need different binaries generated for different architectures and so on.
I could be wrong but I think nix is focused more on just the producing the artifact part. I do love how they approach every build as a pure function though.
That is only true to a point. Nix has an extremely broad definition of what constitutes a "build", in practice, and this process can include things like tests.
That having been said, there are undoubtedly certain tasks that Nix itself is not great at - but when you think of Nix more as a system primitive for expressing build processes rather than as a universal do-everything tool, that just means you would build tooling on top of it for those tasks, like Hydra does for CI for example.
That way everybody wins; you don't need to reinvent the build orchestration parts of the process, it interoperates with the entire existing package set, and the broader Nix community gains a new tool that helps them solve their problems more effectively.
So it is a less granular approach than Bazel which we think offers a lot of same benefits but without guaranteed bit for bit reproducibility. You can do non-repeatable things in a `RUN` but if you don't then it works well and you get to use all your existing tooling rather than having to replace them.