287 lines
9.2 KiB
Perl
Executable file
287 lines
9.2 KiB
Perl
Executable file
#! @perl@ -w @perlFlags@
|
||
|
||
use utf8;
|
||
use Fcntl qw(:DEFAULT :flock);
|
||
use English '-no_match_vars';
|
||
use IO::Handle;
|
||
use Nix::Config;
|
||
use Nix::SSH;
|
||
use Nix::CopyClosure;
|
||
use Nix::Store;
|
||
use Encode;
|
||
no warnings('once');
|
||
|
||
STDERR->autoflush(1);
|
||
binmode STDERR, ":encoding(utf8)";
|
||
|
||
my $debug = defined $ENV{NIX_DEBUG_HOOK};
|
||
|
||
setVerbosity(0); # make exportPath() less verbose
|
||
|
||
|
||
# General operation:
|
||
#
|
||
# Try to find a free machine of type $neededSystem. We do this as
|
||
# follows:
|
||
# - We acquire an exclusive lock on $currentLoad/main-lock.
|
||
# - For each machine $machine of type $neededSystem and for each $slot
|
||
# less than the maximum load for that machine, we try to get an
|
||
# exclusive lock on $currentLoad/$machine-$slot (without blocking).
|
||
# If we get such a lock, we send "accept" to the caller. Otherwise,
|
||
# we send "postpone" and exit.
|
||
# - We release the exclusive lock on $currentLoad/main-lock.
|
||
# - We perform the build on $neededSystem.
|
||
# - We release the exclusive lock on $currentLoad/$machine-$slot.
|
||
#
|
||
# The nice thing about this scheme is that if we die prematurely, the
|
||
# locks are released automatically.
|
||
|
||
|
||
# Make sure that we don't get any SSH passphrase or host key popups -
|
||
# if there is any problem it should fail, not do something
|
||
# interactive.
|
||
$ENV{"DISPLAY"} = "";
|
||
$ENV{"SSH_ASKPASS"} = "";
|
||
|
||
|
||
sub sendReply {
|
||
my $reply = shift;
|
||
print STDERR "# $reply\n";
|
||
}
|
||
|
||
sub all { $_ || return 0 for @_; 1 }
|
||
|
||
|
||
# Initialisation.
|
||
my $loadIncreased = 0;
|
||
|
||
my ($localSystem, $maxSilentTime, $printBuildTrace, $buildTimeout) = @ARGV;
|
||
|
||
my $currentLoad = $ENV{"NIX_CURRENT_LOAD"} // "/run/nix/current-load";
|
||
my $conf = $ENV{"NIX_REMOTE_SYSTEMS"} // "@sysconfdir@/nix/machines";
|
||
|
||
|
||
sub openSlotLock {
|
||
my ($machine, $slot) = @_;
|
||
my $slotLockFn = "$currentLoad/" . (join '+', @{$machine->{systemTypes}}) . "-" . $machine->{hostName} . "-$slot";
|
||
my $slotLock = new IO::Handle;
|
||
sysopen $slotLock, "$slotLockFn", O_RDWR|O_CREAT, 0600 or die;
|
||
return $slotLock;
|
||
}
|
||
|
||
|
||
# Read the list of machines.
|
||
my @machines;
|
||
if (defined $conf && -e $conf) {
|
||
open CONF, "<$conf" or die;
|
||
while (<CONF>) {
|
||
chomp;
|
||
s/\#.*$//g;
|
||
next if /^\s*$/;
|
||
my @tokens = split /\s/, $_;
|
||
my @supportedFeatures = split(/,/, $tokens[5] || "");
|
||
my @mandatoryFeatures = split(/,/, $tokens[6] || "");
|
||
push @machines,
|
||
{ hostName => $tokens[0]
|
||
, systemTypes => [ split(/,/, $tokens[1]) ]
|
||
, sshKey => $tokens[2]
|
||
, maxJobs => int($tokens[3])
|
||
, speedFactor => 1.0 * (defined $tokens[4] ? int($tokens[4]) : 1)
|
||
, supportedFeatures => [ @supportedFeatures, @mandatoryFeatures ]
|
||
, mandatoryFeatures => [ @mandatoryFeatures ]
|
||
, enabled => 1
|
||
};
|
||
}
|
||
close CONF;
|
||
}
|
||
|
||
|
||
|
||
# Wait for the calling process to ask us whether we can build some derivation.
|
||
my ($drvPath, $hostName, $slotLock);
|
||
my ($from, $to);
|
||
|
||
REQ: while (1) {
|
||
$_ = <STDIN> || exit 0;
|
||
(my $amWilling, my $neededSystem, $drvPath, my $requiredFeatures) = split;
|
||
my @requiredFeatures = split /,/, $requiredFeatures;
|
||
|
||
my $canBuildLocally = $amWilling && ($localSystem eq $neededSystem);
|
||
|
||
if (!defined $currentLoad) {
|
||
sendReply "decline";
|
||
next;
|
||
}
|
||
|
||
# Acquire the exclusive lock on $currentLoad/main-lock.
|
||
mkdir $currentLoad, 0777 or die unless -d $currentLoad;
|
||
my $mainLock = "$currentLoad/main-lock";
|
||
sysopen MAINLOCK, "$mainLock", O_RDWR|O_CREAT, 0600 or die;
|
||
flock(MAINLOCK, LOCK_EX) or die;
|
||
|
||
|
||
while (1) {
|
||
# Find all machine that can execute this build, i.e., that
|
||
# support builds for the given platform and features, and are
|
||
# not at their job limit.
|
||
my $rightType = 0;
|
||
my @available = ();
|
||
LOOP: foreach my $cur (@machines) {
|
||
if ($cur->{enabled}
|
||
&& (grep { $neededSystem eq $_ } @{$cur->{systemTypes}})
|
||
&& all(map { my $f = $_; 0 != grep { $f eq $_ } @{$cur->{supportedFeatures}} } (@requiredFeatures, @mandatoryFeatures))
|
||
&& all(map { my $f = $_; 0 != grep { $f eq $_ } @requiredFeatures } @{$cur->{mandatoryFeatures}})
|
||
)
|
||
{
|
||
$rightType = 1;
|
||
|
||
# We have a machine of the right type. Determine the load on
|
||
# the machine.
|
||
my $slot = 0;
|
||
my $load = 0;
|
||
my $free;
|
||
while ($slot < $cur->{maxJobs}) {
|
||
my $slotLock = openSlotLock($cur, $slot);
|
||
if (flock($slotLock, LOCK_EX | LOCK_NB)) {
|
||
$free = $slot unless defined $free;
|
||
flock($slotLock, LOCK_UN) or die;
|
||
} else {
|
||
$load++;
|
||
}
|
||
close $slotLock;
|
||
$slot++;
|
||
}
|
||
|
||
push @available, { machine => $cur, load => $load, free => $free }
|
||
if $load < $cur->{maxJobs};
|
||
}
|
||
}
|
||
|
||
if ($debug) {
|
||
print STDERR "load on " . $_->{machine}->{hostName} . " = " . $_->{load} . "\n"
|
||
foreach @available;
|
||
}
|
||
|
||
|
||
# Didn't find any available machine? Then decline or postpone.
|
||
if (scalar @available == 0) {
|
||
# Postpone if we have a machine of the right type, except
|
||
# if the local system can and wants to do the build.
|
||
if ($rightType && !$canBuildLocally) {
|
||
sendReply "postpone";
|
||
} else {
|
||
sendReply "decline";
|
||
}
|
||
close MAINLOCK;
|
||
next REQ;
|
||
}
|
||
|
||
|
||
# Prioritise the available machines as follows:
|
||
# - First by load divided by speed factor, rounded to the nearest
|
||
# integer. This causes fast machines to be preferred over slow
|
||
# machines with similar loads.
|
||
# - Then by speed factor.
|
||
# - Finally by load.
|
||
sub lf { my $x = shift; return int($x->{load} / $x->{machine}->{speedFactor} + 0.4999); }
|
||
@available = sort
|
||
{ lf($a) <=> lf($b)
|
||
|| $b->{machine}->{speedFactor} <=> $a->{machine}->{speedFactor}
|
||
|| $a->{load} <=> $b->{load}
|
||
} @available;
|
||
|
||
|
||
# Select the best available machine and lock a free slot.
|
||
my $selected = $available[0];
|
||
my $machine = $selected->{machine};
|
||
|
||
$slotLock = openSlotLock($machine, $selected->{free});
|
||
flock($slotLock, LOCK_EX | LOCK_NB) or die;
|
||
utime undef, undef, $slotLock;
|
||
|
||
close MAINLOCK;
|
||
|
||
|
||
# Connect to the selected machine.
|
||
my @sshOpts = ("-i", $machine->{sshKey});
|
||
$hostName = $machine->{hostName};
|
||
eval {
|
||
($from, $to) = connectToRemoteNix($hostName, \@sshOpts, "2>&4");
|
||
# FIXME: check if builds are inhibited.
|
||
};
|
||
last REQ unless $@;
|
||
print STDERR "$@";
|
||
warn "unable to open SSH connection to ‘$hostName’, trying other available machines...\n";
|
||
$from = undef;
|
||
$to = undef;
|
||
$machine->{enabled} = 0;
|
||
}
|
||
}
|
||
|
||
|
||
# Tell Nix we've accepted the build.
|
||
sendReply "accept";
|
||
my @inputs = split /\s/, readline(STDIN);
|
||
my @outputs = split /\s/, readline(STDIN);
|
||
|
||
|
||
print STDERR "@ build-remote $drvPath $hostName\n" if $printBuildTrace;
|
||
|
||
|
||
my $maybeSign = "";
|
||
$maybeSign = "--sign" if -e "$Nix::Config::confDir/signing-key.sec";
|
||
|
||
|
||
# Copy the derivation and its dependencies to the build machine. This
|
||
# is guarded by an exclusive lock per machine to prevent multiple
|
||
# build-remote instances from copying to a machine simultaneously.
|
||
# That's undesirable because we may end up with N instances uploading
|
||
# the same missing path simultaneously, causing the effective network
|
||
# bandwidth and target disk speed to be divided by N.
|
||
my $uploadLock = "$currentLoad/$hostName.upload-lock";
|
||
sysopen UPLOADLOCK, "$uploadLock", O_RDWR|O_CREAT, 0600 or die;
|
||
eval {
|
||
local $SIG{ALRM} = sub { die "alarm\n" };
|
||
# Don't wait forever, so that a process that gets stuck while
|
||
# holding the lock doesn't block everybody else indefinitely.
|
||
# It's safe to continue after a timeout, just (potentially)
|
||
# inefficient.
|
||
alarm 15 * 60;
|
||
flock(UPLOADLOCK, LOCK_EX);
|
||
alarm 0;
|
||
};
|
||
if ($@) {
|
||
die unless $@ eq "alarm\n";
|
||
print STDERR "somebody is hogging $uploadLock, continuing...\n";
|
||
unlink $uploadLock;
|
||
}
|
||
Nix::CopyClosure::copyToOpen($from, $to, $hostName, [ $drvPath, @inputs ], 0, 0, $maybeSign ne "");
|
||
close UPLOADLOCK;
|
||
|
||
|
||
# Perform the build.
|
||
print STDERR "building ‘$drvPath’ on ‘$hostName’\n";
|
||
print STDERR "@ build-remote-start $drvPath $hostName\n" if $printBuildTrace;
|
||
writeInt(6, $to) or die; # == cmdBuildPaths
|
||
writeStrings([$drvPath], $to);
|
||
writeInt($maxSilentTime, $to);
|
||
writeInt($buildTimeout, $to);
|
||
my $res = readInt($from);
|
||
print STDERR "@ build-remote-done $drvPath $hostName\n" if $printBuildTrace;
|
||
if ($res != 0) {
|
||
my $msg = decode("utf-8", readString($from));
|
||
print STDERR "error: $msg on ‘$hostName’\n";
|
||
exit $res;
|
||
}
|
||
|
||
|
||
# Copy the output from the build machine.
|
||
my @outputs2 = grep { !isValidPath($_) } @outputs;
|
||
if (scalar @outputs2 > 0) {
|
||
writeInt(5, $to); # == cmdExportPaths
|
||
writeInt(0, $to); # don't sign
|
||
writeStrings(\@outputs2, $to);
|
||
$ENV{'NIX_HELD_LOCKS'} = "@outputs2"; # FIXME: ugly
|
||
importPaths(fileno($from));
|
||
}
|