# Sooner or later this should be implemented in nix itself, for now require »inputs.nixpkgs« and a system that can run »x86_64-linux« (native or through qemu).
# A flake has »{ inputs; outputs; sourceInfo; } // outputs // sourceInfo«, where »inputs« is what's passed to the outputs function without »self«, and »outputs« is the result of calling the outputs function. Don't know the merge priority.
repoPath=builtins.path{path=repoPath';name="source";};# referring to the current flake directory as »./.« is quite intuitive (and »inputs.self.outPath« causes infinite recursion), but without this it adds another hash to the path (because it copies it)
# Given a path to a host config file, returns some properties defined in its first inline module (to be used where accessing them via »nodes.${name}.config...« isn't possible).
# Builds the System Configuration for a single host. Since each host depends on the context of all other host (in the same "network"), this is essentially only callable through »mkNixosConfigurations«.
specialArgs={# make these available in the attrSet passed to the modules
inheritinputs;# These are global and passed by the caller of this function (or not), so avoid using these (in favor of the own flakes inputs) where possible!
specialArgs=specialArgs;# explicitly passing »pkgs« here breaks »config.nixpkgs.overlays«!
});
# Given either a list (or attr set) of »files« (paths to ».nix« or ».nix.md« files for dirs with »default.nix« files in them) or a »dir« path (and optionally a list of file names to »exclude« from it), this builds the NixOS configuration for each host (per file) in the context of all configs provided.
# If »files« is an attr set, exactly one host with the attribute's name as hostname is built for each attribute. Otherwise the default is to build for one host per configuration file, named as the file name without extension or the sub-directory name. Setting »preface.instances« can override this to build the same configuration for those multiple names instead (the specific »name« is passed as additional »specialArgs« to the modules and can thus be used to adjust the config per instance).
# An attrset of imported Nix flakes, for example the argument(s) passed to the flake »outputs« function. All other arguments are optional (and have reasonable defaults) if this is provided and contains »self« and the standard »nixpkgs«. This is also the second argument passed to the individual host's top level config files.
inputs?{},
# Root path of the NixOS configuration. »./.« in the »flake.nix«
configPath?inputs.self.outPath,
# Arguments »{ files, dir, exclude, }« to »mkNixosConfigurations«, see there for details. May also be a list of those attrsets, in which case those multiple sets of hosts will be built separately by »mkNixosConfigurations«, allowing for separate sets of »peers« passed to »mkNixosConfiguration«. Each call will receive all other arguments, and the resulting sets of hosts will be merged.
# (Subset of) »inputs« that »overlays« will be used from. Example: »{ inherit (inputs) self flakeA flakeB; }«.
overlayInputs?inputs,
# List of Modules to import for all hosts, in addition to the default ones in »nixpkgs«. The host-individual module should selectively enable these. Defaults to all »ModuleInputs«/»inputs«' ».nixosModule(s)« (including »inputs.self.nixosModule(s)«).
# (Subset of) »inputs« that »modules« will be used from. (The standard) »nixpkgs« does not export any (useful) modules, since the actual modules are included by default by »nixosSystem«.
# Additional arguments passed to each module evaluated for the host config (if that module is defined as a function).
specialArgs?{},
# List of bash scripts defining functions that do installation and maintenance operations. See »apps« below for more information.
scripts?[],
# The function of that name as defined in »<nixpkgs>/flake.nix«, or equivalent.
nixosSystem?inputs.nixpkgs.lib.nixosSystem,
# If provided, then cross compilation is enabled for all hosts whose target architecture is different from this. Since cross compilation currently fails for (some stuff in) NixOS, better don't set »localSystem«. Without it, building for other platforms works fine (just slowly) if »boot.binfmt.emulatedSystems« is configured on the building system for the respective target(s).
# E.g.: $ nix run .#$target -- install-system /tmp/system-$target.img
# E.g.: $ nix run /etc/nixos/#$(hostname) -- sudo
# If the first argument (after »--«) is »sudo«, then the program will re-execute itself with sudo as root (minus that »sudo« argument).
# If the first/next argument is »bash«, it will execute an interactive shell with the variables and functions sourced (largely equivalent to »nix develop .#$host«).
# if the (now) first arg is »bash« or there are no args, re-execute this script as bash »--init-file«, starting an interactive bash in the context of the script
if[[$1==bash]]||[[$# == 0 && $0 == *-scripts-${name} ]] ; then
