484 lines
		
	
	
		
			17 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			484 lines
		
	
	
		
			17 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
| { config, lib, pkgs, ... }:
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| 
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| with lib;
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| 
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| let
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| 
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|   cfg = config.nix;
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| 
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|   nix = cfg.package.out;
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| 
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|   isNix20 = versionAtLeast (getVersion nix) "2.0pre";
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| 
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|   makeNixBuildUser = nr:
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|     { name = "nixbld${toString nr}";
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|       description = "Nix build user ${toString nr}";
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| 
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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 = map makeNixBuildUser (range 1 cfg.nrBuildUsers);
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| 
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|   nixConf =
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|     let
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|       # In Nix < 2.0, If we're using sandbox for builds, then provide
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|       # /bin/sh in the sandbox as a bind-mount to bash. This means we
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|       # also need to include the entire closure of bash. Nix >= 2.0
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|       # provides a /bin/sh by default.
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|       sh = pkgs.runtimeShell;
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|       binshDeps = pkgs.writeReferencesToFile sh;
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|     in
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|       pkgs.runCommand "nix.conf" { preferLocalBuild = true; extraOptions = cfg.extraOptions; } (''
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|         ${optionalString (!isNix20) ''
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|           extraPaths=$(for i in $(cat ${binshDeps}); do if test -d $i; then echo $i; fi; done)
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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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|         ${if isNix20 then "max-jobs" else "build-max-jobs"} = ${toString (cfg.maxJobs)}
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|         ${if isNix20 then "cores" else "build-cores"} = ${toString (cfg.buildCores)}
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|         ${if isNix20 then "sandbox" else "build-use-sandbox"} = ${if (builtins.isBool cfg.useSandbox) then boolToString cfg.useSandbox else cfg.useSandbox}
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|         ${if isNix20 then "extra-sandbox-paths" else "build-sandbox-paths"} = ${toString cfg.sandboxPaths} ${optionalString (!isNix20) "/bin/sh=${sh} $(echo $extraPaths)"}
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|         ${if isNix20 then "substituters" else "binary-caches"} = ${toString cfg.binaryCaches}
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|         ${if isNix20 then "trusted-substituters" else "trusted-binary-caches"} = ${toString cfg.trustedBinaryCaches}
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|         ${if isNix20 then "trusted-public-keys" else "binary-cache-public-keys"} = ${toString cfg.binaryCachePublicKeys}
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|         auto-optimise-store = ${boolToString cfg.autoOptimiseStore}
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|         ${if isNix20 then ''
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|           require-sigs = ${if cfg.requireSignedBinaryCaches then "true" else "false"}
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|         '' else ''
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|           signed-binary-caches = ${if cfg.requireSignedBinaryCaches then "*" else ""}
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|         ''}
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|         trusted-users = ${toString cfg.trustedUsers}
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|         allowed-users = ${toString cfg.allowedUsers}
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|         ${optionalString (isNix20 && !cfg.distributedBuilds) ''
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|           builders =
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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 >/dev/null
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|             '')
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|       );
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| 
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| in
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| 
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| {
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| 
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|   ###### interface
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| 
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|   options = {
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| 
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|     nix = {
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| 
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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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| 
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|       maxJobs = mkOption {
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|         type = types.either types.int (types.enum ["auto"]);
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|         default = 1;
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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
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|           to build in parallel.  The default is 1.  You should generally
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|           set it to the total number of logical cores in your system (e.g., 16
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|           for two CPUs with 4 cores each and hyper-threading).
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|         '';
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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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| 
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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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| 
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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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| 
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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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| 
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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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|           gc-keep-outputs = true
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|           gc-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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| 
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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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| 
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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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| 
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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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| 
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|       buildMachines = mkOption {
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|         type = types.listOf types.attrs;
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|         default = [];
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|         example = literalExample ''
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|           [ { hostName = "voila.labs.cs.uu.nl";
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|               sshUser = "nix";
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|               sshKey = "/root/.ssh/id_buildfarm";
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|               system = "powerpc-darwin";
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|               maxJobs = 1;
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|             }
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|             { hostName = "linux64.example.org";
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|               sshUser = "buildfarm";
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|               sshKey = "/root/.ssh/id_buildfarm";
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|               system = "x86_64-linux";
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|               maxJobs = 2;
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|               speedFactor = 2;
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|               supportedFeatures = [ "kvm" ];
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|               mandatoryFeatures = [ "perf" ];
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|             }
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|           ]
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|         '';
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|         description = ''
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|           This option lists the machines to be used if distributed
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|           builds are enabled (see
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|           <option>nix.distributedBuilds</option>).  Nix will perform
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|           derivations on those machines via SSH by copying the inputs
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|           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.  Each
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|           element of the list should be an attribute set containing
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|           the machine's host name (<varname>hostname</varname>), the
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|           user name to be used for the SSH connection
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|           (<varname>sshUser</varname>), the Nix system type
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|           (<varname>system</varname>, e.g.,
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|           <literal>"i686-linux"</literal>), the maximum number of
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|           jobs to be run in parallel on that machine
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|           (<varname>maxJobs</varname>), the path to the SSH private
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|           key to be used to connect (<varname>sshKey</varname>), a
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|           list of supported features of the machine
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|           (<varname>supportedFeatures</varname>) and a list of
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|           mandatory features of the machine
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|           (<varname>mandatoryFeatures</varname>). The SSH private key
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|           should not have a passphrase, and the corresponding public
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|           key should be added to
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|           <filename>~<replaceable>sshUser</replaceable>/authorized_keys</filename>
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|           on the remote machine.
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|         '';
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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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| 
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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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| 
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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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| 
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|       binaryCaches = mkOption {
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|         type = types.listOf types.str;
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|         default = [ https://cache.nixos.org/ ];
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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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|         '';
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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 = [ http://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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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|     };
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| 
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|   };
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| 
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| 
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|   ###### implementation
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| 
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|   config = {
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| 
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|     nix.binaryCachePublicKeys = [ "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=" ];
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| 
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|     environment.etc."nix/nix.conf".source = nixConf;
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| 
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|     # List of machines for distributed Nix builds in the format
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|     # expected by build-remote.pl.
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|     environment.etc."nix/machines" =
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|       { enable = cfg.buildMachines != [];
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|         text =
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|           concatMapStrings (machine:
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|             "${if machine ? sshUser then "${machine.sshUser}@" else ""}${machine.hostName} "
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|             + machine.system or (concatStringsSep "," machine.systems)
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|             + " ${machine.sshKey or "-"} ${toString machine.maxJobs or 1} "
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|             + toString (machine.speedFactor or 1)
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|             + " "
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|             + concatStringsSep "," (machine.mandatoryFeatures or [] ++ machine.supportedFeatures or [])
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|             + " "
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|             + concatStringsSep "," machine.mandatoryFeatures or []
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|             + "\n"
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|           ) cfg.buildMachines;
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|       };
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| 
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|     systemd.packages = [ nix ];
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| 
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|     systemd.sockets.nix-daemon.wantedBy = [ "sockets.target" ];
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| 
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|     systemd.services.nix-daemon =
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|       { path = [ nix pkgs.utillinux config.programs.ssh.package ]
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|           ++ optionals cfg.distributedBuilds [ pkgs.gzip ]
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|           ++ optionals (!isNix20) [ pkgs.openssl.bin ];
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| 
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|         environment = cfg.envVars
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|           // { CURL_CA_BUNDLE = "/etc/ssl/certs/ca-certificates.crt"; }
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|           // config.networking.proxy.envVars;
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| 
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|         unitConfig.RequiresMountsFor = "/nix/store";
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| 
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|         serviceConfig =
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|           { Nice = cfg.daemonNiceLevel;
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|             IOSchedulingPriority = cfg.daemonIONiceLevel;
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|             LimitNOFILE = 4096;
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|           };
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| 
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|         restartTriggers = [ nixConf ];
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|       };
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| 
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|     nix.envVars =
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|       optionalAttrs (!isNix20) {
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|         NIX_CONF_DIR = "/etc/nix";
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| 
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|         # Enable the copy-from-other-stores substituter, which allows
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|         # builds to be sped up by copying build results from remote
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|         # Nix stores.  To do this, mount the remote file system on a
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|         # subdirectory of /run/nix/remote-stores.
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|         NIX_OTHER_STORES = "/run/nix/remote-stores/*/nix";
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|       }
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| 
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|       // optionalAttrs (cfg.distributedBuilds && !isNix20) {
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|         NIX_BUILD_HOOK = "${nix}/libexec/nix/build-remote.pl";
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|       };
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| 
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|     # Set up the environment variables for running Nix.
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|     environment.sessionVariables = cfg.envVars //
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|       { NIX_PATH = cfg.nixPath;
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|       };
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| 
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|     environment.extraInit = optionalString (!isNix20)
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|       ''
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|         # Set up secure multi-user builds: non-root users build through the
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|         # Nix daemon.
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|         if [ "$USER" != root -o ! -w /nix/var/nix/db ]; then
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|             export NIX_REMOTE=daemon
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|         fi
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|       '' + ''
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|         if [ -e "$HOME/.nix-defexpr/channels" ]; then
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|           export NIX_PATH="$HOME/.nix-defexpr/channels''${NIX_PATH:+:$NIX_PATH}"
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|         fi
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|       '';
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| 
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|     nix.nrBuildUsers = mkDefault (lib.max 32 cfg.maxJobs);
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| 
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|     users.users = nixbldUsers;
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| 
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|     services.xserver.displayManager.hiddenUsers = map ({ name, ... }: name) nixbldUsers;
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| 
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|     # FIXME: use systemd-tmpfiles to create Nix directories.
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|     system.activationScripts.nix = stringAfter [ "etc" "users" ]
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|       ''
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|         # Nix initialisation.
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|         install -m 0755 -d \
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|           /nix/var/nix/gcroots \
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|           /nix/var/nix/temproots \
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|           /nix/var/nix/userpool \
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|           /nix/var/nix/profiles \
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|           /nix/var/nix/db \
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|           /nix/var/log/nix/drvs
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|         install -m 1777 -d \
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|           /nix/var/nix/gcroots/per-user \
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|           /nix/var/nix/profiles/per-user \
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|           /nix/var/nix/gcroots/tmp
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|       '';
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| 
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|   };
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| 
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| }
 | 
