From 2b0aea17934fda4aca24d4b6b99f0b9c24486ff7 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Mon, 18 Nov 2013 16:51:39 +0100 Subject: [PATCH] Allow running NixOS services outside of systemd MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The attribute ‘config.systemd.services..runner’ generates a script that runs the service outside of systemd. This is useful for testing, and also allows NixOS services to be used outside of NixOS. For instance, given a configuration file foo.nix: { config, pkgs, ... }: { services.postgresql.enable = true; services.postgresql.package = pkgs.postgresql92; services.postgresql.dataDir = "/tmp/postgres"; } you can build and run PostgreSQL as follows: $ nix-build -A config.systemd.services.postgresql.runner -I nixos-config=./foo.nix $ ./result This will run the service's ExecStartPre, ExecStart, ExecStartPost and ExecStopPost commands in an appropriate environment. It doesn't work well yet for "forking" services, since it can't track the main process. It also doesn't work for services that assume they're always executed by root. --- nixos/modules/module-list.nix | 1 + .../modules/services/databases/postgresql.nix | 9 +- nixos/modules/testing/service-runner.nix | 114 ++++++++++++++++++ 3 files changed, 122 insertions(+), 2 deletions(-) create mode 100644 nixos/modules/testing/service-runner.nix diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix index 09625511bba5..caba5ef18c3c 100644 --- a/nixos/modules/module-list.nix +++ b/nixos/modules/module-list.nix @@ -274,6 +274,7 @@ ./tasks/network-interfaces.nix ./tasks/scsi-link-power-management.nix ./tasks/swraid.nix + ./testing/service-runner.nix ./virtualisation/libvirtd.nix #./virtualisation/nova.nix ./virtualisation/virtualbox-guest.nix diff --git a/nixos/modules/services/databases/postgresql.nix b/nixos/modules/services/databases/postgresql.nix index 73447e3cf0d8..a1ab1c92b8f9 100644 --- a/nixos/modules/services/databases/postgresql.nix +++ b/nixos/modules/services/databases/postgresql.nix @@ -181,8 +181,13 @@ in # Initialise the database. if ! test -e ${cfg.dataDir}; then mkdir -m 0700 -p ${cfg.dataDir} - chown -R postgres ${cfg.dataDir} - su -s ${pkgs.stdenv.shell} postgres -c 'initdb -U root' + if [ "$(id -u)" = 0 ]; then + chown -R postgres ${cfg.dataDir} + su -s ${pkgs.stdenv.shell} postgres -c 'initdb -U root' + else + # For non-root operation. + initdb + fi rm -f ${cfg.dataDir}/*.conf touch "${cfg.dataDir}/.first_startup" fi diff --git a/nixos/modules/testing/service-runner.nix b/nixos/modules/testing/service-runner.nix new file mode 100644 index 000000000000..6f17ed77dad9 --- /dev/null +++ b/nixos/modules/testing/service-runner.nix @@ -0,0 +1,114 @@ +{ config, pkgs, ... }: + +with pkgs.lib; + +let + + makeScript = name: service: pkgs.writeScript "${name}-runner" + '' + #! ${pkgs.perl}/bin/perl -w -I${pkgs.perlPackages.FileSlurp}/lib/perl5/site_perl + + use File::Slurp; + + sub run { + my ($cmd) = @_; + my @args = split " ", $cmd; + my $prog; + if (substr($args[0], 0, 1) eq "@") { + $prog = substr($args[0], 1); + shift @args; + } else { + $prog = $args[0]; + } + my $pid = fork; + if ($pid == 0) { + setpgrp; # don't receive SIGINT etc. from terminal + exec { $prog } @args; + die "failed to exec $prog\n"; + } elsif (!defined $pid) { + die "failed to fork: $!\n"; + } + return $pid; + }; + + sub run_wait { + my ($cmd) = @_; + my $pid = run $cmd; + die if waitpid($pid, 0) != $pid; + return $?; + }; + + # Set the environment. FIXME: escaping. + foreach my $key (keys %ENV) { + next if $key eq 'LOCALE_ARCHIVE'; + delete $ENV{$key}; + } + ${concatStrings (mapAttrsToList (n: v: '' + $ENV{'${n}'} = '${v}'; + '') service.environment)} + + # Run the ExecStartPre program. FIXME: this could be a list. + my $preStart = '${service.serviceConfig.ExecStartPre or ""}'; + if ($preStart ne "") { + print STDERR "running ExecStartPre: $preStart\n"; + my $res = run_wait $preStart; + die "$0: ExecStartPre failed with status $res\n" if $res; + }; + + # Run the ExecStart program. + my $cmd = '${service.serviceConfig.ExecStart}'; + print STDERR "running ExecStart: $cmd\n"; + my $mainPid = run $cmd; + $ENV{'MAINPID'} = $mainPid; + + # Catch SIGINT, propagate to the main program. + sub intHandler { + print STDERR "got SIGINT, stopping service...\n"; + kill 'INT', $mainPid; + }; + $SIG{'INT'} = \&intHandler; + $SIG{'QUIT'} = \&intHandler; + + # Run the ExecStartPost program. + my $postStart = '${service.serviceConfig.ExecStartPost or ""}'; + if ($postStart ne "") { + print STDERR "running ExecStartPost: $postStart\n"; + my $res = run_wait $postStart; + die "$0: ExecStartPost failed with status $res\n" if $res; + } + + # Wait for the main program to exit. + die if waitpid($mainPid, 0) != $mainPid; + my $mainRes = $?; + + # Run the ExecStopPost program. + my $postStop = '${service.serviceConfig.ExecStopPost or ""}'; + if ($postStop ne "") { + print STDERR "running ExecStopPost: $postStop\n"; + my $res = run_wait $postStop; + die "$0: ExecStopPost failed with status $res\n" if $res; + } + + exit($mainRes & 127 ? 255 : $mainRes << 8); + ''; + +in + +{ + options = { + systemd.services = mkOption { + options = + { config, name, ... }: + { options.runner = mkOption { + internal = true; + description = '' + A script that runs the service outside of systemd, + useful for testing or for using NixOS services outside + of NixOS. + ''; + }; + config.runner = makeScript name config; + }; + }; + }; +}