2e751c0772
the conversion procedure is simple: - find all things that look like options, ie calls to either `mkOption` or `lib.mkOption` that take an attrset. remember the attrset as the option - for all options, find a `description` attribute who's value is not a call to `mdDoc` or `lib.mdDoc` - textually convert the entire value of the attribute to MD with a few simple regexes (the set from mdize-module.sh) - if the change produced a change in the manual output, discard - if the change kept the manual unchanged, add some text to the description to make sure we've actually found an option. if the manual changes this time, keep the converted description this procedure converts 80% of nixos options to markdown. around 2000 options remain to be inspected, but most of those fail the "does not change the manual output check": currently the MD conversion process does not faithfully convert docbook tags like <code> and <package>, so any option using such tags will not be converted at all.
87 lines
2.7 KiB
Nix
87 lines
2.7 KiB
Nix
{ config, lib, pkgs, ... }:
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with lib;
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let
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cfg = config.virtualisation.amazon-init;
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script = ''
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#!${pkgs.runtimeShell} -eu
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echo "attempting to fetch configuration from EC2 user data..."
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export HOME=/root
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export PATH=${pkgs.lib.makeBinPath [ config.nix.package config.systemd.package pkgs.gnugrep pkgs.git pkgs.gnutar pkgs.gzip pkgs.gnused pkgs.xz config.system.build.nixos-rebuild]}:$PATH
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export NIX_PATH=nixpkgs=/nix/var/nix/profiles/per-user/root/channels/nixos:nixos-config=/etc/nixos/configuration.nix:/nix/var/nix/profiles/per-user/root/channels
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userData=/etc/ec2-metadata/user-data
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# Check if user-data looks like a shell script and execute it with the
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# runtime shell if it does. Otherwise treat it as a nixos configuration
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# expression
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if IFS= LC_ALL=C read -rN2 shebang < $userData && [ "$shebang" = '#!' ]; then
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# NB: we cannot chmod the $userData file, this is why we execute it via
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# `pkgs.runtimeShell`. This means we have only limited support for shell
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# scripts compatible with the `pkgs.runtimeShell`.
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exec ${pkgs.runtimeShell} $userData
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fi
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if [ -s "$userData" ]; then
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# If the user-data looks like it could be a nix expression,
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# copy it over. Also, look for a magic three-hash comment and set
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# that as the channel.
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if sed '/^\(#\|SSH_HOST_.*\)/d' < "$userData" | grep -q '\S'; then
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channels="$(grep '^###' "$userData" | sed 's|###\s*||')"
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while IFS= read -r channel; do
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echo "writing channel: $channel"
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done < <(printf "%s\n" "$channels")
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if [[ -n "$channels" ]]; then
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printf "%s" "$channels" > /root/.nix-channels
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nix-channel --update
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fi
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echo "setting configuration from EC2 user data"
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cp "$userData" /etc/nixos/configuration.nix
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else
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echo "user data does not appear to be a Nix expression; ignoring"
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exit
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fi
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else
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echo "no user data is available"
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exit
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fi
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nixos-rebuild switch
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'';
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in {
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options.virtualisation.amazon-init = {
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enable = mkOption {
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default = true;
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type = types.bool;
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description = lib.mdDoc ''
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Enable or disable the amazon-init service.
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'';
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};
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};
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config = mkIf cfg.enable {
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systemd.services.amazon-init = {
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inherit script;
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description = "Reconfigure the system from EC2 userdata on startup";
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wantedBy = [ "multi-user.target" ];
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after = [ "multi-user.target" ];
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requires = [ "network-online.target" ];
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restartIfChanged = false;
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unitConfig.X-StopOnRemoval = false;
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serviceConfig = {
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Type = "oneshot";
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RemainAfterExit = true;
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};
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};
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};
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}
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