600 lines
		
	
	
		
			21 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			600 lines
		
	
	
		
			21 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
{ config, lib, pkgs, ... }:
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with lib;
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let
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  cfg = config.nix;
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  nix = cfg.package.out;
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  nixVersion = getVersion nix;
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  isNix23 = versionAtLeast nixVersion "2.3pre";
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  makeNixBuildUser = nr: {
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    name  = "nixbld${toString nr}";
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    value = {
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      description = "Nix build user ${toString nr}";
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      /* For consistency with the setgid(2), setuid(2), and setgroups(2)
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         calls in `libstore/build.cc', don't add any supplementary group
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         here except "nixbld".  */
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      uid = builtins.add config.ids.uids.nixbld nr;
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      group = "nixbld";
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      extraGroups = [ "nixbld" ];
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    };
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  };
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  nixbldUsers = listToAttrs (map makeNixBuildUser (range 1 cfg.nrBuildUsers));
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  nixConf =
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    assert versionAtLeast nixVersion "2.2";
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    pkgs.runCommand "nix.conf" { preferLocalBuild = true; extraOptions = cfg.extraOptions; } (
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      ''
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        cat > $out <<END
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        # WARNING: this file is generated from the nix.* options in
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        # your NixOS configuration, typically
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        # /etc/nixos/configuration.nix.  Do not edit it!
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        build-users-group = nixbld
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        max-jobs = ${toString (cfg.maxJobs)}
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        cores = ${toString (cfg.buildCores)}
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        sandbox = ${if (builtins.isBool cfg.useSandbox) then boolToString cfg.useSandbox else cfg.useSandbox}
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        extra-sandbox-paths = ${toString cfg.sandboxPaths}
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        substituters = ${toString cfg.binaryCaches}
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        trusted-substituters = ${toString cfg.trustedBinaryCaches}
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        trusted-public-keys = ${toString cfg.binaryCachePublicKeys}
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        auto-optimise-store = ${boolToString cfg.autoOptimiseStore}
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        require-sigs = ${if cfg.requireSignedBinaryCaches then "true" else "false"}
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        trusted-users = ${toString cfg.trustedUsers}
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        allowed-users = ${toString cfg.allowedUsers}
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        ${optionalString (!cfg.distributedBuilds) ''
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          builders =
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        ''}
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        system-features = ${toString cfg.systemFeatures}
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        ${optionalString isNix23 ''
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          sandbox-fallback = false
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        ''}
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        $extraOptions
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        END
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      '' + optionalString cfg.checkConfig (
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            if pkgs.stdenv.hostPlatform != pkgs.stdenv.buildPlatform then ''
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              echo "Ignore nix.checkConfig when cross-compiling"
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            '' else ''
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              echo "Checking that Nix can read nix.conf..."
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              ln -s $out ./nix.conf
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              NIX_CONF_DIR=$PWD ${cfg.package}/bin/nix show-config ${optionalString isNix23 "--no-net --option experimental-features nix-command"} >/dev/null
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            '')
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      );
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in
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{
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  imports = [
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    (mkRenamedOptionModule [ "nix" "useChroot" ] [ "nix" "useSandbox" ])
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    (mkRenamedOptionModule [ "nix" "chrootDirs" ] [ "nix" "sandboxPaths" ])
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  ];
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  ###### interface
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  options = {
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    nix = {
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      package = mkOption {
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        type = types.package;
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        default = pkgs.nix;
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        defaultText = "pkgs.nix";
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        description = ''
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          This option specifies the Nix package instance to use throughout the system.
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        '';
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      };
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      maxJobs = mkOption {
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        type = types.either types.int (types.enum ["auto"]);
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        default = "auto";
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        example = 64;
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        description = ''
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          This option defines the maximum number of jobs that Nix will try to
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          build in parallel. The default is auto, which means it will use all
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          available logical cores. It is recommend to set it to the total
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          number of logical cores in your system (e.g., 16 for two CPUs with 4
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          cores each and hyper-threading).
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        '';
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      };
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      autoOptimiseStore = mkOption {
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        type = types.bool;
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        default = false;
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        example = true;
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        description = ''
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         If set to true, Nix automatically detects files in the store that have
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         identical contents, and replaces them with hard links to a single copy.
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         This saves disk space. If set to false (the default), you can still run
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         nix-store --optimise to get rid of duplicate files.
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        '';
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      };
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      buildCores = mkOption {
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        type = types.int;
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        default = 0;
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        example = 64;
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        description = ''
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          This option defines the maximum number of concurrent tasks during
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          one build. It affects, e.g., -j option for make.
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          The special value 0 means that the builder should use all
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          available CPU cores in the system. Some builds may become
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          non-deterministic with this option; use with care! Packages will
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          only be affected if enableParallelBuilding is set for them.
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        '';
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      };
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      useSandbox = mkOption {
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        type = types.either types.bool (types.enum ["relaxed"]);
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        default = true;
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        description = "
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          If set, Nix will perform builds in a sandboxed environment that it
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          will set up automatically for each build. This prevents impurities
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          in builds by disallowing access to dependencies outside of the Nix
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          store by using network and mount namespaces in a chroot environment.
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          This is enabled by default even though it has a possible performance
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          impact due to the initial setup time of a sandbox for each build. It
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          doesn't affect derivation hashes, so changing this option will not
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          trigger a rebuild of packages.
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        ";
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      };
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      sandboxPaths = mkOption {
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        type = types.listOf types.str;
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        default = [];
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        example = [ "/dev" "/proc" ];
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        description =
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          ''
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            Directories from the host filesystem to be included
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            in the sandbox.
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          '';
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      };
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      extraOptions = mkOption {
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        type = types.lines;
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        default = "";
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        example = ''
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          keep-outputs = true
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          keep-derivations = true
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        '';
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        description = "Additional text appended to <filename>nix.conf</filename>.";
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      };
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      distributedBuilds = mkOption {
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        type = types.bool;
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        default = false;
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        description = ''
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          Whether to distribute builds to the machines listed in
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          <option>nix.buildMachines</option>.
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        '';
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      };
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      daemonNiceLevel = mkOption {
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        type = types.int;
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        default = 0;
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        description = ''
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          Nix daemon process priority. This priority propagates to build processes.
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          0 is the default Unix process priority, 19 is the lowest.
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        '';
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      };
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      daemonIONiceLevel = mkOption {
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        type = types.int;
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        default = 0;
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        description = ''
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          Nix daemon process I/O priority. This priority propagates to build processes.
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          0 is the default Unix process I/O priority, 7 is the lowest.
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        '';
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      };
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      buildMachines = mkOption {
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        type = types.listOf (types.submodule ({
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          options = {
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            hostName = mkOption {
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              type = types.str;
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              example = "nixbuilder.example.org";
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              description = ''
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                The hostname of the build machine.
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              '';
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            };
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            system = mkOption {
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              type = types.nullOr types.str;
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              default = null;
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              example = "x86_64-linux";
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              description = ''
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                The system type the build machine can execute derivations on.
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                Either this attribute or <varname>systems</varname> must be
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                present, where <varname>system</varname> takes precedence if
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                both are set.
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              '';
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            };
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            systems = mkOption {
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              type = types.listOf types.str;
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              default = [];
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              example = [ "x86_64-linux" "aarch64-linux" ];
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              description = ''
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                The system types the build machine can execute derivations on.
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                Either this attribute or <varname>system</varname> must be
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                present, where <varname>system</varname> takes precedence if
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                both are set.
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              '';
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            };
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            sshUser = mkOption {
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              type = types.nullOr types.str;
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              default = null;
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              example = "builder";
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              description = ''
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                The username to log in as on the remote host. This user must be
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                able to log in and run nix commands non-interactively. It must
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                also be privileged to build derivations, so must be included in
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                <option>nix.trustedUsers</option>.
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              '';
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            };
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            sshKey = mkOption {
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              type = types.nullOr types.str;
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              default = null;
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              example = "/root/.ssh/id_buildhost_builduser";
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              description = ''
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                The path to the SSH private key with which to authenticate on
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                the build machine. The private key must not have a passphrase.
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                If null, the building user (root on NixOS machines) must have an
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                appropriate ssh configuration to log in non-interactively.
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                Note that for security reasons, this path must point to a file
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                in the local filesystem, *not* to the nix store.
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              '';
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            };
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            maxJobs = mkOption {
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              type = types.int;
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              default = 1;
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              description = ''
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                The number of concurrent jobs the build machine supports. The
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                build machine will enforce its own limits, but this allows hydra
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                to schedule better since there is no work-stealing between build
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                machines.
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              '';
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            };
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            speedFactor = mkOption {
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              type = types.int;
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              default = 1;
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              description = ''
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                The relative speed of this builder. This is an arbitrary integer
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                that indicates the speed of this builder, relative to other
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                builders. Higher is faster.
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              '';
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            };
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            mandatoryFeatures = mkOption {
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              type = types.listOf types.str;
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              default = [];
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              example = [ "big-parallel" ];
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              description = ''
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                A list of features mandatory for this builder. The builder will
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                be ignored for derivations that don't require all features in
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                this list. All mandatory features are automatically included in
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                <varname>supportedFeatures</varname>.
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              '';
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            };
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            supportedFeatures = mkOption {
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              type = types.listOf types.str;
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              default = [];
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              example = [ "kvm" "big-parallel" ];
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              description = ''
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                A list of features supported by this builder. The builder will
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                be ignored for derivations that require features not in this
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                list.
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              '';
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            };
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          };
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        }));
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        default = [];
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        description = ''
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          This option lists the machines to be used if distributed builds are
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          enabled (see <option>nix.distributedBuilds</option>).
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          Nix will perform derivations on those machines via SSH by copying the
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          inputs to the Nix store on the remote machine, starting the build,
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          then copying the output back to the local Nix store.
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        '';
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      };
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      # Environment variables for running Nix.
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      envVars = mkOption {
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        type = types.attrs;
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        internal = true;
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        default = {};
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        description = "Environment variables used by Nix.";
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      };
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      nrBuildUsers = mkOption {
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        type = types.int;
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        description = ''
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          Number of <literal>nixbld</literal> user accounts created to
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          perform secure concurrent builds.  If you receive an error
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          message saying that “all build users are currently in use”,
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          you should increase this value.
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        '';
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      };
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      readOnlyStore = mkOption {
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        type = types.bool;
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        default = true;
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        description = ''
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          If set, NixOS will enforce the immutability of the Nix store
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          by making <filename>/nix/store</filename> a read-only bind
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          mount.  Nix will automatically make the store writable when
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          needed.
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        '';
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      };
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      binaryCaches = mkOption {
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        type = types.listOf types.str;
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        description = ''
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          List of binary cache URLs used to obtain pre-built binaries
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          of Nix packages.
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          By default https://cache.nixos.org/ is added,
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          to override it use <literal>lib.mkForce []</literal>.
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        '';
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      };
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      trustedBinaryCaches = mkOption {
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        type = types.listOf types.str;
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        default = [ ];
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        example = [ "https://hydra.nixos.org/" ];
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        description = ''
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          List of binary cache URLs that non-root users can use (in
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          addition to those specified using
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          <option>nix.binaryCaches</option>) by passing
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          <literal>--option binary-caches</literal> to Nix commands.
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        '';
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      };
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      requireSignedBinaryCaches = mkOption {
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        type = types.bool;
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        default = true;
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        description = ''
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          If enabled (the default), Nix will only download binaries from binary caches if
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          they are cryptographically signed with any of the keys listed in
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          <option>nix.binaryCachePublicKeys</option>. If disabled, signatures are neither
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          required nor checked, so it's strongly recommended that you use only
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          trustworthy caches and https to prevent man-in-the-middle attacks.
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        '';
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      };
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      binaryCachePublicKeys = mkOption {
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        type = types.listOf types.str;
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        example = [ "hydra.nixos.org-1:CNHJZBh9K4tP3EKF6FkkgeVYsS3ohTl+oS0Qa8bezVs=" ];
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        description = ''
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          List of public keys used to sign binary caches. If
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          <option>nix.requireSignedBinaryCaches</option> is enabled,
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          then Nix will use a binary from a binary cache if and only
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          if it is signed by <emphasis>any</emphasis> of the keys
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          listed here. By default, only the key for
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          <uri>cache.nixos.org</uri> is included.
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        '';
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      };
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      trustedUsers = mkOption {
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        type = types.listOf types.str;
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        default = [ "root" ];
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        example = [ "root" "alice" "@wheel" ];
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        description = ''
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          A list of names of users that have additional rights when
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          connecting to the Nix daemon, such as the ability to specify
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          additional binary caches, or to import unsigned NARs. You
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          can also specify groups by prefixing them with
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          <literal>@</literal>; for instance,
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          <literal>@wheel</literal> means all users in the wheel
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          group.
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        '';
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      };
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      allowedUsers = mkOption {
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        type = types.listOf types.str;
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        default = [ "*" ];
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        example = [ "@wheel" "@builders" "alice" "bob" ];
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        description = ''
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          A list of names of users (separated by whitespace) that are
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          allowed to connect to the Nix daemon. As with
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          <option>nix.trustedUsers</option>, you can specify groups by
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          prefixing them with <literal>@</literal>. Also, you can
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          allow all users by specifying <literal>*</literal>. The
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          default is <literal>*</literal>. Note that trusted users are
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          always allowed to connect.
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        '';
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      };
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      nixPath = mkOption {
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        type = types.listOf types.str;
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        default =
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          [
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            "nixpkgs=/nix/var/nix/profiles/per-user/root/channels/nixos"
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            "nixos-config=/etc/nixos/configuration.nix"
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            "/nix/var/nix/profiles/per-user/root/channels"
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          ];
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        description = ''
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          The default Nix expression search path, used by the Nix
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          evaluator to look up paths enclosed in angle brackets
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          (e.g. <literal><nixpkgs></literal>).
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        '';
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      };
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      systemFeatures = mkOption {
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        type = types.listOf types.str;
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        example = [ "kvm" "big-parallel" "gccarch-skylake" ];
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        description = ''
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          The supported features of a machine
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        '';
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      };
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      checkConfig = mkOption {
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        type = types.bool;
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        default = true;
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        description = ''
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          If enabled (the default), checks that Nix can parse the generated nix.conf.
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        '';
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      };
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      registry = mkOption {
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        type = types.attrsOf (types.submodule (
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          let
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            inputAttrs = types.attrsOf (types.oneOf [types.str types.int types.bool types.package]);
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          in
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          { config, name, ... }:
 | 
						|
          { options = {
 | 
						|
              from = mkOption {
 | 
						|
                type = inputAttrs;
 | 
						|
                example = { type = "indirect"; id = "nixpkgs"; };
 | 
						|
                description = "The flake reference to be rewritten.";
 | 
						|
              };
 | 
						|
              to = mkOption {
 | 
						|
                type = inputAttrs;
 | 
						|
                example = { type = "github"; owner = "my-org"; repo = "my-nixpkgs"; };
 | 
						|
                description = "The flake reference to which <option>from></option> is to be rewritten.";
 | 
						|
              };
 | 
						|
              flake = mkOption {
 | 
						|
                type = types.unspecified;
 | 
						|
                default = null;
 | 
						|
                example = literalExample "nixpkgs";
 | 
						|
                description = ''
 | 
						|
                  The flake input to which <option>from></option> is to be rewritten.
 | 
						|
                '';
 | 
						|
              };
 | 
						|
              exact = mkOption {
 | 
						|
                type = types.bool;
 | 
						|
                default = true;
 | 
						|
                description = ''
 | 
						|
                  Whether the <option>from</option> reference needs to match exactly. If set,
 | 
						|
                  a <option>from</option> reference like <literal>nixpkgs</literal> does not
 | 
						|
                  match with a reference like <literal>nixpkgs/nixos-20.03</literal>.
 | 
						|
                '';
 | 
						|
              };
 | 
						|
            };
 | 
						|
            config = {
 | 
						|
              from = mkDefault { type = "indirect"; id = name; };
 | 
						|
              to = mkIf (config.flake != null)
 | 
						|
                ({ type = "path";
 | 
						|
                   path = config.flake.outPath;
 | 
						|
                 } // lib.filterAttrs
 | 
						|
                   (n: v: n == "lastModified" || n == "rev" || n == "revCount" || n == "narHash")
 | 
						|
                   config.flake);
 | 
						|
            };
 | 
						|
          }
 | 
						|
        ));
 | 
						|
        default = {};
 | 
						|
        description = ''
 | 
						|
          A system-wide flake registry.
 | 
						|
        '';
 | 
						|
      };
 | 
						|
 | 
						|
    };
 | 
						|
 | 
						|
  };
 | 
						|
 | 
						|
 | 
						|
  ###### implementation
 | 
						|
 | 
						|
  config = {
 | 
						|
 | 
						|
    nix.binaryCachePublicKeys = [ "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=" ];
 | 
						|
    nix.binaryCaches = [ "https://cache.nixos.org/" ];
 | 
						|
 | 
						|
    environment.systemPackages =
 | 
						|
      [ nix
 | 
						|
        pkgs.nix-info
 | 
						|
      ]
 | 
						|
      ++ optional (config.programs.bash.enableCompletion && !versionAtLeast nixVersion "2.4pre") pkgs.nix-bash-completions;
 | 
						|
 | 
						|
    environment.etc."nix/nix.conf".source = nixConf;
 | 
						|
 | 
						|
    environment.etc."nix/registry.json".text = builtins.toJSON {
 | 
						|
      version = 2;
 | 
						|
      flakes = mapAttrsToList (n: v: { inherit (v) from to exact; }) cfg.registry;
 | 
						|
    };
 | 
						|
 | 
						|
    # List of machines for distributed Nix builds in the format
 | 
						|
    # expected by build-remote.pl.
 | 
						|
    environment.etc."nix/machines" =
 | 
						|
      { enable = cfg.buildMachines != [];
 | 
						|
        text =
 | 
						|
          concatMapStrings (machine:
 | 
						|
            "${if machine.sshUser != null then "${machine.sshUser}@" else ""}${machine.hostName} "
 | 
						|
            + (if machine.system != null then machine.system else concatStringsSep "," machine.systems)
 | 
						|
            + " ${if machine.sshKey != null then machine.sshKey else "-"} ${toString machine.maxJobs} "
 | 
						|
            + toString (machine.speedFactor)
 | 
						|
            + " "
 | 
						|
            + concatStringsSep "," (machine.mandatoryFeatures ++ machine.supportedFeatures)
 | 
						|
            + " "
 | 
						|
            + concatStringsSep "," machine.mandatoryFeatures
 | 
						|
            + "\n"
 | 
						|
          ) cfg.buildMachines;
 | 
						|
      };
 | 
						|
 | 
						|
    systemd.packages = [ nix ];
 | 
						|
 | 
						|
    systemd.sockets.nix-daemon.wantedBy = [ "sockets.target" ];
 | 
						|
 | 
						|
    systemd.services.nix-daemon =
 | 
						|
      { path = [ nix pkgs.utillinux config.programs.ssh.package ]
 | 
						|
          ++ optionals cfg.distributedBuilds [ pkgs.gzip ];
 | 
						|
 | 
						|
        environment = cfg.envVars
 | 
						|
          // { CURL_CA_BUNDLE = "/etc/ssl/certs/ca-certificates.crt"; }
 | 
						|
          // config.networking.proxy.envVars;
 | 
						|
 | 
						|
        unitConfig.RequiresMountsFor = "/nix/store";
 | 
						|
 | 
						|
        serviceConfig =
 | 
						|
          { Nice = cfg.daemonNiceLevel;
 | 
						|
            IOSchedulingPriority = cfg.daemonIONiceLevel;
 | 
						|
            LimitNOFILE = 4096;
 | 
						|
          };
 | 
						|
 | 
						|
        restartTriggers = [ nixConf ];
 | 
						|
      };
 | 
						|
 | 
						|
    # Set up the environment variables for running Nix.
 | 
						|
    environment.sessionVariables = cfg.envVars //
 | 
						|
      { NIX_PATH = cfg.nixPath;
 | 
						|
      };
 | 
						|
 | 
						|
    environment.extraInit =
 | 
						|
      ''
 | 
						|
        if [ -e "$HOME/.nix-defexpr/channels" ]; then
 | 
						|
          export NIX_PATH="$HOME/.nix-defexpr/channels''${NIX_PATH:+:$NIX_PATH}"
 | 
						|
        fi
 | 
						|
      '';
 | 
						|
 | 
						|
    nix.nrBuildUsers = mkDefault (lib.max 32 (if cfg.maxJobs == "auto" then 0 else cfg.maxJobs));
 | 
						|
 | 
						|
    users.users = nixbldUsers;
 | 
						|
 | 
						|
    services.xserver.displayManager.hiddenUsers = attrNames nixbldUsers;
 | 
						|
 | 
						|
    system.activationScripts.nix = stringAfter [ "etc" "users" ]
 | 
						|
      ''
 | 
						|
        install -m 0755 -d /nix/var/nix/{gcroots,profiles}/per-user
 | 
						|
 | 
						|
        # Subscribe the root user to the NixOS channel by default.
 | 
						|
        if [ ! -e "/root/.nix-channels" ]; then
 | 
						|
            echo "${config.system.defaultChannel} nixos" > "/root/.nix-channels"
 | 
						|
        fi
 | 
						|
      '';
 | 
						|
 | 
						|
    nix.systemFeatures = mkDefault (
 | 
						|
      [ "nixos-test" "benchmark" "big-parallel" "kvm" ] ++
 | 
						|
      optionals (pkgs.hostPlatform.platform ? gcc.arch) (
 | 
						|
        # a builder can run code for `platform.gcc.arch` and inferior architectures
 | 
						|
        [ "gccarch-${pkgs.hostPlatform.platform.gcc.arch}" ] ++
 | 
						|
        map (x: "gccarch-${x}") lib.systems.architectures.inferiors.${pkgs.hostPlatform.platform.gcc.arch}
 | 
						|
      )
 | 
						|
    );
 | 
						|
 | 
						|
  };
 | 
						|
 | 
						|
}
 |