{pkgs, config, ...}:
with pkgs.lib;
###### interface
let
options = {
environment = {
nix = mkOption {
default = pkgs.nixUnstable;
example = pkgs.nixCustomFun /root/nix.tar.gz;
merge = mergeOneOption;
description = "
This option specifies the Nix package instance to use throughout the system.
";
};
};
nix = {
maxJobs = mkOption {
default = 1;
example = 2;
description = "
This option defines the maximum number of jobs that Nix will try
to build in parallel. The default is 1. You should generally
set it to the number of CPUs in your system (e.g., 2 on a Athlon
64 X2).
";
};
useChroot = mkOption {
default = false;
example = true;
description = "
If set, Nix will perform builds in a chroot-environment that it
will set up automatically for each build. This prevents
impurities in builds by disallowing access to dependencies
outside of the Nix store.
";
};
extraOptions = mkOption {
default = "";
example = "
gc-keep-outputs = true
gc-keep-derivations = true
";
description = "
This option allows to append lines to nix.conf.
";
};
distributedBuilds = mkOption {
default = false;
description = "
Whether to distribute builds to the machines listed in
<option>nix.buildMachines</option>.
";
};
buildMachines = mkOption {
example = [
{ hostName = "voila.labs.cs.uu.nl";
sshUser = "nix";
sshKey = "/root/.ssh/id_buildfarm";
system = "powerpc-darwin";
maxJobs = 1;
}
{ hostName = "linux64.example.org";
sshUser = "buildfarm";
sshKey = "/root/.ssh/id_buildfarm";
system = "x86_64-linux";
maxJobs = 2;
}
];
description = "
This option lists the machines to be used if distributed
builds are enabled (see
<option>nix.distributedBuilds</option>). Nix will perform
derivations on those machines via SSh by copying the inputs to
the Nix store on the remote machine, starting the build, then
copying the output back to the local Nix store. Each element
of the list should be an attribute set containing the
machine's host name (<varname>hostname</varname>), the user
name to be used for the SSH connection
(<varname>sshUser</varname>), the Nix system type
(<varname>system</varname>, e.g.,
<literal>\"i686-linux\"</literal>), the maximum number of jobs
to be run in parallel on that machine
(<varname>maxJobs</varname>), and the path to the SSH private
key to be used to connect (<varname>sshKey</varname>). The
SSH private key should not have a passphrase, and the
corresponding public key should be added to
<filename>~<replaceable>sshUser</replaceable>/authorized_keys</filename>
on the remote machine.
";
};
proxy = mkOption {
default = "";
description = "
This option specifies the proxy to use for fetchurl. The real effect
is just exporting http_proxy, https_proxy and ftp_proxy with that
value.
";
example = "http://127.0.0.1:3128";
};
# Environment variables for running Nix.
# !!! Fix description.
envVars = mkOption {
internal = true;
default = "";
description = "
Define the environment variables used by nix to
";
merge = pkgs.lib.mergeStringOption;
# other option should be used to define the content instead of using
# the apply function.
apply = conf: ''
export NIX_CONF_DIR=/nix/etc/nix
# Enable the copy-from-other-stores substituter, which allows builds
# to be sped up by copying build results from remote Nix stores. To
# do this, mount the remote file system on a subdirectory of
# /var/run/nix/remote-stores.
export NIX_OTHER_STORES=/var/run/nix/remote-stores/*/nix
'' + # */
(if config.nix.distributedBuilds then
''
export NIX_BUILD_HOOK=${config.environment.nix}/libexec/nix/build-remote.pl
export NIX_REMOTE_SYSTEMS=/etc/nix.machines
export NIX_CURRENT_LOAD=/var/run/nix/current-load
''
else "")
+
(if config.nix.proxy != "" then
''
export http_proxy=${config.nix.proxy}
export https_proxy=${config.nix.proxy}
export ftp_proxy=${config.nix.proxy}
''
else "")
+ conf;
};
services = {
pulseaudio = {
enable = mkOption {
default = false;
description = ''
Whether to enable the PulseAudio system-wide audio server.
Note that the documentation recommends running PulseAudio
daemons per-user rather than system-wide on desktop machines.
'';
};
logLevel = mkOption {
default = "notice";
example = "debug";
description = ''
A string denoting the log level: one of
<literal>error</literal>, <literal>warn</literal>,
<literal>notice</literal>, <literal>info</literal>,
or <literal>debug</literal>.
'';
};
};
};
};
};
in
###### implementation
let
inherit (config.environment) nix;
in
{
require = [
options
];
environment.etc =
[ { # Nix configuration.
source =
let
# Tricky: if we're using a chroot for builds, then we need
# /bin/sh in the chroot (our own compromise to purity).
# However, since /bin/sh is a symlink to some path in the
# Nix store, which furthermore has runtime dependencies on
# other paths in the store, we need the closure of /bin/sh
# in `build-chroot-dirs' - otherwise any builder that uses
# /bin/sh won't work.
binshDeps = pkgs.writeReferencesToFile config.system.build.binsh;
# Likewise, if chroots are turned on, we need Nix's own
# closure in the chroot. Otherwise nix-channel and nix-env
# won't work because the dependencies of its builders (like
# coreutils and Perl) aren't visible. Sigh.
nixDeps = pkgs.writeReferencesToFile config.environment.nix;
in
pkgs.runCommand "nix.conf" {extraOptions = config.nix.extraOptions; } ''
extraPaths=$(for i in $(cat ${binshDeps} ${nixDeps}); do if test -d $i; then echo $i; fi; done)
cat > $out <<END
# WARNING: this file is generated.
build-users-group = nixbld
build-max-jobs = ${toString (config.nix.maxJobs)}
build-use-chroot = ${if config.nix.useChroot then "true" else "false"}
build-chroot-dirs = /dev /dev/pts /proc /bin $(echo $extraPaths)
$extraOptions
END
'';
target = "nix.conf"; # will be symlinked from /nix/etc/nix/nix.conf in activate-configuration.sh.
}
]
++ optional config.nix.distributedBuilds
{ # List of machines for distributed Nix builds in the format expected
# by build-remote.pl.
source = pkgs.writeText "nix.machines"
(pkgs.lib.concatStrings (map (machine:
"${machine.sshUser}@${machine.hostName} ${machine.system} ${machine.sshKey} ${toString machine.maxJobs}\n"
) config.nix.buildMachines));
target = "nix.machines";
};
jobs = pkgs.lib.singleton
{ name = "nix-daemon";
startOn = "startup";
script =
''
export PATH=${if config.nix.distributedBuilds then "${pkgs.openssh}/bin:" else ""}${pkgs.openssl}/bin:${nix}/bin:$PATH
${config.nix.envVars}
exec ${nix}/bin/nix-worker --daemon > /dev/null 2>&1
'';
};
environment.shellInit =
''
# Set up the environment variables for running Nix.
${config.nix.envVars}
# Set up secure multi-user builds: non-root users build through the
# Nix daemon.
if test "$USER" != root; then
export NIX_REMOTE=daemon
else
export NIX_REMOTE=
fi
'';
}