119c8f91e7
Setting nixosVersion to something custom is useful for meaningful GRUB menus and /nix/store paths, but actuallly changing it rebulids the whole system path (because of `nixos-version` script and manual pages). Also, changing it is not a particularly good idea because you can then be differentitated from other NixOS users by a lot of programs that read /etc/os-release. This patch introduces an alternative option that does all you want from nixosVersion, but rebuilds only the very top system level and /etc while using your label in the names of system /nix/store paths, GRUB and other boot loaders' menus, getty greetings and so on.
126 lines
3.6 KiB
Nix
126 lines
3.6 KiB
Nix
{ config, lib, pkgs, ... }:
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with lib;
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let
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cfg = config.system;
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releaseFile = "${toString pkgs.path}/.version";
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suffixFile = "${toString pkgs.path}/.version-suffix";
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revisionFile = "${toString pkgs.path}/.git-revision";
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in
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{
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options.system = {
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stateVersion = mkOption {
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type = types.str;
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default = cfg.nixosRelease;
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description = ''
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Every once in a while, a new NixOS release may change
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configuration defaults in a way incompatible with stateful
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data. For instance, if the default version of PostgreSQL
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changes, the new version will probably be unable to read your
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existing databases. To prevent such breakage, you can set the
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value of this option to the NixOS release with which you want
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to be compatible. The effect is that NixOS will option
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defaults corresponding to the specified release (such as using
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an older version of PostgreSQL).
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'';
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};
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nixosLabel = mkOption {
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type = types.str;
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description = ''
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NixOS version name to be used in the names of generated
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outputs and boot labels.
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If you ever wanted to influence the labels in your GRUB menu,
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this is option is for you.
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Can be set directly or with <envar>NIXOS_LABEL</envar>
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environment variable for <command>nixos-rebuild</command>,
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e.g.:
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<screen>
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#!/bin/sh
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today=`date +%Y%m%d`
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branch=`(cd nixpkgs ; git branch 2>/dev/null | sed -n '/^\* / { s|^\* ||; p; }')`
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revision=`(cd nixpkgs ; git rev-parse HEAD)`
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export NIXOS_LABEL="$today.$branch-''${revision:0:7}"
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nixos-rebuild switch</screen>
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'';
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};
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nixosVersion = mkOption {
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internal = true;
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type = types.str;
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description = "NixOS version.";
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};
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nixosRelease = mkOption {
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readOnly = true;
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type = types.str;
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default = readFile releaseFile;
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description = "NixOS release.";
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};
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nixosVersionSuffix = mkOption {
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internal = true;
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type = types.str;
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default = if pathExists suffixFile then readFile suffixFile else "pre-git";
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description = "NixOS version suffix.";
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};
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nixosRevision = mkOption {
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internal = true;
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type = types.str;
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default = if pathExists revisionFile then readFile revisionFile else "master";
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description = "NixOS Git revision hash.";
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};
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nixosCodeName = mkOption {
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readOnly = true;
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type = types.str;
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description = "NixOS release code name.";
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};
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defaultChannel = mkOption {
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internal = true;
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type = types.str;
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default = https://nixos.org/channels/nixos-unstable;
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description = "Default NixOS channel to which the root user is subscribed.";
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};
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};
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config = {
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system = {
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# These defaults are set here rather than up there so that
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# changing them would not rebuild the manual
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nixosLabel = mkDefault (maybeEnv "NIXOS_LABEL" cfg.nixosVersion);
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nixosVersion = mkDefault (maybeEnv "NIXOS_VERSION" (cfg.nixosRelease + cfg.nixosVersionSuffix));
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# Note: code names must only increase in alphabetical order.
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nixosCodeName = "Emu";
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};
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# Generate /etc/os-release. See
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# http://0pointer.de/public/systemd-man/os-release.html for the
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# format.
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environment.etc."os-release".text =
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''
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NAME=NixOS
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ID=nixos
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VERSION="${config.system.nixosVersion} (${config.system.nixosCodeName})"
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VERSION_ID="${config.system.nixosVersion}"
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PRETTY_NAME="NixOS ${config.system.nixosVersion} (${config.system.nixosCodeName})"
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HOME_URL="http://nixos.org/"
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'';
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};
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}
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