lix/perl/lib/Nix/CopyClosure.pm
2014-07-11 14:27:17 +02:00

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package Nix::CopyClosure;
use strict;
use Nix::Config;
use Nix::Store;
use List::Util qw(sum);
use IPC::Open2;
sub readN {
my ($bytes, $from) = @_;
my $res = "";
while ($bytes > 0) {
my $s;
my $n = sysread($from, $s, $bytes);
die "I/O error reading from remote side\n" if !defined $n;
die "got EOF while expecting $bytes bytes from remote side\n" if !$n;
$bytes -= $n;
$res .= $s;
}
return $res;
}
sub readInt {
my ($from) = @_;
return unpack("L<x4", readN(8, $from));
}
sub writeString {
my ($s, $to) = @_;
my $len = length $s;
my $req .= pack("L<x4", $len);
$req .= $s;
$req .= "\000" x (8 - $len % 8) if $len % 8;
syswrite($to, $req) or die;
}
sub copyTo {
my ($sshHost, $sshOpts, $storePaths, $compressor, $decompressor,
$includeOutputs, $dryRun, $sign, $progressViewer, $useSubstitutes) = @_;
$useSubstitutes = 0 if $dryRun;
# Get the closure of this path.
my @closure = reverse(topoSortPaths(computeFSClosure(0, $includeOutputs,
map { followLinksToStorePath $_ } @{$storePaths})));
# Start nix-store --serve on the remote host.
my ($from, $to);
my $pid = open2($from, $to, "ssh $sshHost @{$sshOpts} nix-store --serve --write");
# Do the handshake.
eval {
my $SERVE_MAGIC_1 = 0x390c9deb; # FIXME
my $clientVersion = 0x200;
syswrite($to, pack("L<x4L<x4", $SERVE_MAGIC_1, $clientVersion)) or die;
die "did not get valid handshake from remote host\n" if readInt($from) != 0x5452eecb;
my $serverVersion = readInt($from);
die "unsupported server version\n" if $serverVersion < 0x200 || $serverVersion >= 0x300;
};
if ($@) {
chomp $@;
warn "$@; falling back to old closure copying method\n";
return oldCopyTo(\@closure, @_);
}
# Send the "query valid paths" command with the "lock" option
# enabled. This prevents a race where the remote host
# garbage-collect paths that are already there. Optionally, ask
# the remote host to substitute missing paths.
syswrite($to, pack("L<x4L<x4L<x4L<x4", 1, 1, $useSubstitutes, scalar @closure)) or die;
writeString($_, $to) foreach @closure;
# Get back the set of paths that are already valid on the remote host.
my %present;
my $n = readInt($from);
while ($n--) {
my $len = readInt($from);
my $s = readN($len, $from);
$present{$s} = 1;
readN(8 - $len % 8, $from) if $len % 8; # skip padding
}
my @missing = grep { !$present{$_} } @closure;
return if !@missing;
my $missingSize = 0;
$missingSize += (queryPathInfo($_, 1))[3] foreach @missing;
printf STDERR "copying %d missing paths (%.2f MiB) to $sshHost...\n",
scalar(@missing), $missingSize / (1024**2);
return if $dryRun;
# Send the "import paths" command.
syswrite($to, pack("L<x4", 4)) or die;
writeString($compressor, $to);
if ($compressor || $progressViewer) {
# Compute the size of the closure for the progress viewer.
$progressViewer = "$progressViewer -s $missingSize" if $progressViewer;
# Start the compressor and/or progress viewer in between us
# and the remote host.
my $to_;
my $pid2 = open2(">&" . fileno($to), $to_,
$progressViewer && $compressor ? "$progressViewer | $compressor" : $progressViewer || $compressor);
close $to;
exportPaths(fileno($to_), $sign, @missing);
close $to_;
waitpid $pid2, 0;
} else {
exportPaths(fileno($to), $sign, @missing);
close $to;
}
readInt($from) == 1 or die "remote machine \`$sshHost' failed to import closure\n";
}
# For backwards compatibility with Nix <= 1.7. Will be removed
# eventually.
sub oldCopyTo {
my ($closure, $sshHost, $sshOpts, $storePaths, $compressor, $decompressor,
$includeOutputs, $dryRun, $sign, $progressViewer, $useSubstitutes) = @_;
# Optionally use substitutes on the remote host.
if (!$dryRun && $useSubstitutes) {
system "ssh $sshHost @{$sshOpts} nix-store -r --ignore-unknown @$closure";
# Ignore exit status because this is just an optimisation.
}
# Ask the remote host which paths are invalid. Because of limits
# to the command line length, do this in chunks. Eventually,
# we'll want to use --from-stdin, but we can't rely on the
# target having this option yet.
my @missing;
my $missingSize = 0;
while (scalar(@$closure) > 0) {
my @ps = splice(@$closure, 0, 1500);
open(READ, "set -f; ssh $sshHost @{$sshOpts} nix-store --check-validity --print-invalid @ps|");
while (<READ>) {
chomp;
push @missing, $_;
my ($deriver, $narHash, $time, $narSize, $refs) = queryPathInfo($_, 1);
$missingSize += $narSize;
}
close READ or die;
}
$compressor = "$compressor |" if $compressor ne "";
$decompressor = "$decompressor |" if $decompressor ne "";
$progressViewer = "$progressViewer -s $missingSize |" if $progressViewer ne "";
# Export the store paths and import them on the remote machine.
if (scalar @missing > 0) {
print STDERR "copying ", scalar @missing, " missing paths to $sshHost...\n";
unless ($dryRun) {
open SSH, "| $progressViewer $compressor ssh $sshHost @{$sshOpts} '$decompressor nix-store --import' > /dev/null" or die;
exportPaths(fileno(SSH), $sign, @missing);
close SSH or die "copying store paths to remote machine `$sshHost' failed: $?";
}
}
}
1;