dockernix
Docker container and basic tooling for running nix on docker for macos.
This is useful if you run a macos workstation, but need a Linux Nix environment to build and test your code.
Setup
Prerequisites
- A Mac
- Docker for Mac
It assumes you put all of your code checkouts under ~/src.
Installing
- Clone this repo.
cdinto the repo folder and run these commands:
docker volume create nix
./build-dockernix
ln -s "`pwd`/nix-shell-docker" ~/bin
ln -s "`pwd`/start-dockernix" ~/bin
ln -s "`pwd`/stop-dockernix" ~/bin
I don't currently run nix on macos, so I rename the first link to nix-shell.
Usage
Firstly, run start-dockernix to start up.
Then, use nix-shell-docker just like you would nix-shell. cd into your project folder and run nix-shell-docker.
If you want to shut down the container: stop-dockernix.
How it works
The docker image is based on a simple minimal nixos build.
/nix is in a volume, so you don't lose your cache between restarts.
start-dockernix starts the container and keeps it alive with a dummy process.
This container has the nix volume mounted, and also mounts your ~/src folder as ~/src in the container.
nix-shell-docker runs docker exec against this container.
It calls into a simple script on the container, which cds into your current folder mounted on the container,
and passes the rest of its arguments through to nix-shell.
The effect is fairly seamless. Pretend you're nix-ing on Linux.
Why one container?
We could run each nix-shell in its own container, but I was concerned about a few things:
- do we need to?
- startup time
- nix store size
- concurrent access to nix store from multiple containers
Maybe these aren't a big deal - fork the repo and try it.
Customizing
Tweak start-dockernix to change the mount points you expose.
Tweak the Dockerfile and run build-dockernix, e.g. if you want to use a different Nix channel.
As mentioned above, you could rename/alias so the command is nix-shell instead of nix-shell-docker.
Potential enhancements
Support a few other commands, like nix-build.
Bundle this up into a homebrew package.
Links
Provisioning a NixOS server from macOS