NixDevImgs

Rationale

For developing, running and building software in a deterministic environment, we have come to know and love (optionally direnv-powered) devShells (from flake outputs), or shell.nix (the "former" way.)

To achieve (almost) identical build environments in container images we use in CI/CD pipelines on (e.g. gitlab-) runners, it would be cool if we could automatically reproduce said devShell environment in a container image.

Now we can

Usage (flake)

The devShell

To enter the devShell:

nix develop path/to/flake-dir#<devenv>

where <devenv> is the name of your environment, corresponding to a directory name under ./devenvs.

For this to work there must be a corresponding shell definition in ./devenvs/<name>/devshell.nix

Or automatically load the devShell by having a working direnv and put in your .envrc:

#!/usr/bin/env bash
# .envrc
...
use flake path/to/flake-dir#<devenvs>
...

Build and Push an Image

To build a compressed container image archive to /nix/store/... (using buildLayeredImage):

nix build path/to/flake-dir#<devenv>
podman load <./result   # or docker

To build the image and upload it to our internal registry:

REGISTRY="docker://1nnoserv:15000" REPO="devops-imgs" nix run path/to/flake-dir#push2reg-<devenv>

or for a public registry (e.g.):

REGISTRY="quay.io" REGACCOUNT=reguser DOCKERHUBTOKEN=regpasswd REPO="devops-imgs" nix run path/to/flake-dir#push2reg-<devenv>
# the target will be expanded to:
# quay.io/reguser/devops-imgs/imageName:imageTags
# where imageName and imageTags are set in the flake

Support

You're very welcome to provide PRs with additional environments (i.e. dirs under ./devenvs), especially for relatively generic cases.

You're also very welcome to help with below TODOs.

TODO

• provide a flake template, that allows users to instantiate as a new flake and provide their own ./devenvs/.... Possibly we could even have the template instantiate selected <devenv> dirs, such that we could use it as the "env provider" for specific cases while using appropriate examples from this repo as a starting point?
• How to build containers for other archs?