Nix flakes for the Oxford Ion Trap Quantum Computing group

This repository contains derivations for deploying ARTIQ via the Nix package manager.

To use, first set up Nix as described on its website. Make sure you have version 2.4 or higher (tested: 2.6). Both single-user and multi-user installs work fine for our purposes. If you choose the latter, you will probably want to add your user to the trusted users to be able to mark the binary caches as trusted (see below).

Then, to set up an environment suitable for running artiq_master and related processes, clone this repository, e.g. into your scratch folder:

$ cd ~/scratch
$ git clone https://github.com/OxfordIonTrapGroup/nix-oitg.git

Now, just run nix develop and follow the instructions on screen:

$ nix develop ~/scratch/nix-oitg

Binary caches/substituters

The Nix flake, together with its dependencies, provides a complete set of instructions on how to build all the components necessary to run ARTIQ from scratch (i.e., the respective source code). This, however, is quite a slow process, as it includes big projects such as LLVM, Rust, Python, etc. As building everything from source every time clearly isn't necessary, Nix allows one to configure "substituters", servers that can provide pre-built binary packages to be downloaded and extracted in place of re-running the build process locally on each machine.

This flake configure two extra substituters: First, our local build server (10.255.6.197) for custom packages and fast installs, and, as a fallback, the M-Labs build server. While we have some customisations to ARTIQ itself, the latter is still useful for things like Rust and LLVM, even though in normal use, those binaries should also be cached by our build server.

The former is accessed via SSH through a special, locked-down nix-ssh user. Authentication should already be set up on the group network, but note that Nix rejects connection to hosts the SSH host keys of which are not known, rather than prompting you. Thus, before running nix develop, make sure to connect to the build server at least once:

$ ssh nix-ssh@10.255.6.197

If everything works, you should get a PTY allocation request failed on channel 0 error message, at which point you can close the session (e.g. by pressing Ctrl-C).

If you are running Nix in multi-user mode, be sure to run this as the root user instead:

$ sudo ssh nix-ssh@10.255.6.197

Use outside Oxford

This flake pulls in several packages that are internal to the Oxford Ion Trap Quantum Computing group, and hosted on our private GitLab instance (gitlab.physics.ox.ac.uk). However, at this stage, none of these contain any modifications necessary to make use of our open-source projects (e.g. ndscan) in your laboratory. If you do want to re-use this somewhat idiosyncratic method of deploying ARTIQ as well, you will need to comment out the Oxford-specific packages in flake.nix and change the URLs for artiq.git etc. to refer to the public upstream repositories instead.

Development notes

Please keep the Nix code formatted using nixfmt. You can easily get it from Nix itself, e.g. using nix shell nixpkgs#nixfmt.