367 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			367 lines
		
	
	
		
			12 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;
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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 ${toString nr}";
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| 
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|       /* For consistency with the setgid(2), setuid(2), and setgroups(2)
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|          calls in `libstore/build.cc', don't add any supplementary group
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|          here except "nixbld".  */
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|       uid = builtins.add config.ids.uids.nixbld nr;
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|       group = "nixbld";
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|       extraGroups = [ "nixbld" ];
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|     };
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| 
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|   nixConf =
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|     let
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|       # If we're using a chroot for builds, then provide /bin/sh in
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|       # the chroot as a bind-mount to bash. This means we also need to
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|       # include the entire closure of bash.
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|       sh = pkgs.stdenv.shell;
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|       binshDeps = pkgs.writeReferencesToFile sh;
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|     in
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|       pkgs.runCommand "nix.conf" {extraOptions = cfg.extraOptions; } ''
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|         extraPaths=$(for i in $(cat ${binshDeps}); do if test -d $i; then echo $i; fi; done)
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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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|         build-max-jobs = ${toString (cfg.maxJobs)}
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|         build-cores = ${toString (cfg.buildCores)}
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|         build-use-chroot = ${if cfg.useChroot then "true" else "false"}
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|         build-chroot-dirs = ${toString cfg.chrootDirs} /bin/sh=${sh} $(echo $extraPaths)
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|         binary-caches = ${toString cfg.binaryCaches}
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|         trusted-binary-caches = ${toString cfg.trustedBinaryCaches}
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|         $extraOptions
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|         END
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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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|         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.int;
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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 number of CPUs in your system (e.g., 2 on an Athlon
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|           64 X2).
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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 = 1;
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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. The default is 1.
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|           Some builds may become non-deterministic with this option; use with
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|           care! Packages will only be affected if enableParallelBuilding is
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|           set for them.
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|         '';
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|       };
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| 
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|       useChroot = mkOption {
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|         type = types.bool;
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|         default = false;
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|         description = "
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|           If set, Nix will perform builds in a chroot-environment that it
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|           will set up automatically for each build.  This prevents
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|           impurities in builds by disallowing access to dependencies
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|           outside of the Nix store.
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|         ";
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|       };
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| 
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|       chrootDirs = 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 chroot.
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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, 20 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 = [
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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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|             supportedFeatures = "kvm";
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|             mandatoryFeatures = "perf";
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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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|       proxy = mkOption {
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|         type = types.str;
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|         default = "";
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|         description = ''
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|           This option specifies the proxy to use for fetchurl. The real effect
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|           is just exporting http_proxy, https_proxy and ftp_proxy with that
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|           value.
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|         '';
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|         example = "http://127.0.0.1:3128";
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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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|         default = 10;
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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 = [ http://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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|     };
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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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|     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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|             "${machine.sshUser}@${machine.hostName} "
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|             + (if machine ? system then machine.system else concatStringsSep "," machine.systems)
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|             + " ${machine.sshKey} ${toString machine.maxJobs} "
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|             + (if machine ? speedFactor then toString machine.speedFactor else "1" )
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|             + " "
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|             + (if machine ? supportedFeatures then concatStringsSep "," machine.supportedFeatures else "" )
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|             + " "
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|             + (if machine ? mandatoryFeatures then concatStringsSep "," machine.mandatoryFeatures else "" )
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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.openssl pkgs.utillinux pkgs.openssh ]
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|           ++ optionals cfg.distributedBuilds [ pkgs.gzip ];
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| 
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|         environment = cfg.envVars // { CURL_CA_BUNDLE = "/etc/ssl/certs/ca-bundle.crt"; };
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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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|       { 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 {
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|         NIX_BUILD_HOOK = "${nix}/libexec/nix/build-remote.pl";
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|         NIX_REMOTE_SYSTEMS = "/etc/nix/machines";
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|         NIX_CURRENT_LOAD = "/run/nix/current-load";
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|       }
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| 
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|       # !!! These should not be defined here, but in some general proxy configuration module!
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|       // optionalAttrs (cfg.proxy != "") {
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|         http_proxy = cfg.proxy;
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|         https_proxy = cfg.proxy;
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|         ftp_proxy = cfg.proxy;
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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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| 
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|     environment.extraInit =
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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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| 
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|     users.extraUsers = map makeNixBuildUser (range 1 cfg.nrBuildUsers);
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| 
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|     system.activationScripts.nix = stringAfter [ "etc" "users" ]
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|       ''
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|         # Nix initialisation.
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|         mkdir -m 0755 -p \
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|           /nix/var/nix/gcroots \
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|           /nix/var/nix/temproots \
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|           /nix/var/nix/manifests \
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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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|           /nix/var/nix/channel-cache
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|         mkdir -m 1777 -p \
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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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|         ln -sf /nix/var/nix/profiles /nix/var/nix/gcroots/
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|         ln -sf /nix/var/nix/manifests /nix/var/nix/gcroots/
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|       '';
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| 
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|   };
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| 
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| }
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