channel-scripts/mirror-channel.pl
Eelco Dolstra e9f69209fc * Enable xz compression of NARs.
git-svn-id: https://nixos.org/repos/nix/release/trunk/channels@34727 70bd8c7a-acb8-0310-9f0d-9cc1c95dcdbb
2013-05-23 20:23:58 +00:00

179 lines
6.6 KiB
Perl

# This script mirrors a remote Nix channel in the local filesystem.
# It downloads the remote manifest, then any NAR files that are not
# already available in the target directory.
use strict;
use Nix::Manifest;
use Nix::GeneratePatches;
use Nix::Utils;
use Nix::Store;
use File::Basename;
use File::stat;
if (scalar @ARGV < 4 || scalar @ARGV > 6) {
print STDERR "Syntax: perl mirror-channel.pl <src-channel-url> <dst-channel-dir> <nar-dir> <nar-url> [<all-patches-manifest [<nix-exprs-url>]]\n";
exit 1;
}
my $curl = "curl --location --silent --show-error --fail";
my $srcChannelURL = $ARGV[0];
my $dstChannelPath = $ARGV[1];
my $cacheDir = $ARGV[2];
my $cacheURL = $ARGV[3];
my $allPatchesManifest = $ARGV[4] || "";
my $nixexprsURL = $ARGV[5];
die "$dstChannelPath doesn't exist\n" unless -d $dstChannelPath;
die "$cacheDir doesn't exist\n" unless -d $cacheDir;
my $manifestPath = "$dstChannelPath/MANIFEST";
my $narDir = "$cacheDir/nar";
# Fetch the manifest.
system("$curl '$srcChannelURL/MANIFEST' > $dstChannelPath/MANIFEST") == 0 or die;
if (defined $nixexprsURL) {
# Mirror nixexprs.tar.xz.
system("$curl '$nixexprsURL' > $dstChannelPath/nixexprs.tar.xz") == 0 or die "cannot download `$nixexprsURL'";
# Generate nixexprs.tar.bz2 for backwards compatibility.
system("xz -d < $dstChannelPath/nixexprs.tar.xz | bzip2 > $dstChannelPath/nixexprs.tar.bz2") == 0 or die "cannot recompress nixexprs.tar";
}
# Advertise a binary cache.
open FILE, ">$dstChannelPath/binary-cache-url" or die;
print FILE "http://nixos.org/binary-cache/" or die;
close FILE or die;
# Read the manifest.
my (%narFiles, %patches);
readManifest("$dstChannelPath/MANIFEST", \%narFiles, \%patches);
%patches = (); # not supported yet
my $size = scalar (keys %narFiles);
print STDERR "$size store paths in manifest\n";
# Protect against Hydra problems that leave the channel empty.
die "cowardly refusing to mirror an empty channel" if $size == 0;
sub permute {
my @list = @_;
for (my $n = scalar @list - 1; $n > 0; $n--) {
my $k = int(rand($n + 1)); # 0 <= $k <= $n
@list[$n, $k] = @list[$k, $n];
}
return @list;
}
sub queryPathHash16 {
my ($storePath) = @_;
my ($deriver, $narHash, $time, $narSize, $refs) = queryPathInfo($storePath, 0);
return $narHash;
}
# Download every file that we don't already have, and update every URL
# to point to the mirror. Also fill in the size and hash fields in
# the manifest in order to be compatible with Nix < 0.13.
foreach my $storePath (permute(keys %narFiles)) {
my $nars = $narFiles{$storePath};
my $pathHash = substr(basename($storePath), 0, 32);
my $narInfoFile = "$cacheDir/$pathHash.narinfo";
foreach my $nar (@{$nars}) {
if (! -e $narInfoFile) {
my $dstFileTmp = "$narDir/.tmp.$$.nar.$nar->{narHash}";
my $ext;
if (isValidPath($storePath) && queryPathHash16($storePath) eq $nar->{narHash}) {
print STDERR "copying $storePath instead of downloading $nar->{url}\n";
# Verify that $storePath hasn't been corrupted and compress it at the same time.
$ext = "xz";
my $narHash = `bash -c 'exec 4>&1; nix-store --dump $storePath | tee >(nix-hash --type sha256 --flat /dev/stdin >&4) | xz -7 > $dstFileTmp'`;
chomp $narHash;
die "hash mismatch in `$storePath'" if "sha256:$narHash" ne $nar->{narHash};
} else {
print STDERR "downloading $nar->{url}\n";
system("$curl '$nar->{url}' > $dstFileTmp") == 0 or die "failed to download `$nar->{url}'";
# Verify whether the downloaded file is a bzipped NAR file
# that matches the NAR hash given in the manifest.
$ext = "bz2";
my $narHash = `bunzip2 < $dstFileTmp | nix-hash --type sha256 --flat /dev/stdin` or die;
chomp $narHash;
die "hash mismatch in downloaded file `$nar->{url}'" if "sha256:$narHash" ne $nar->{narHash};
}
# Compute the hash of the compressed NAR (Hydra doesn't provide one).
my $fileHash = `nix-hash --flat --type sha256 --base32 '$dstFileTmp'` or die;
chomp $fileHash;
$nar->{hash} = "sha256:$fileHash";
my $dstFile = "$narDir/$fileHash.nar.$ext";
if (-e $dstFile) {
unlink($dstFileTmp) or die;
} else {
rename($dstFileTmp, $dstFile) or die "cannot rename $dstFileTmp to $dstFile";
}
$nar->{size} = stat($dstFile)->size;
# Write the .narinfo.
my $info;
$info .= "StorePath: $storePath\n";
$info .= "URL: nar/$fileHash.nar.$ext\n";
$info .= "Compression: " . ($ext eq "xz" ? "xz" : "bzip2") . "\n";
$info .= "FileHash: $nar->{hash}\n";
$info .= "FileSize: $nar->{size}\n";
$info .= "NarHash: $nar->{narHash}\n";
$info .= "NarSize: $nar->{narSize}\n";
$info .= "References: " . join(" ", map { basename $_ } (split " ", $nar->{references})) . "\n";
$info .= "Deriver: " . basename $nar->{deriver} . "\n" if $nar->{deriver} ne "";
$info .= "System: $nar->{system}\n" if defined $nar->{system};
my $tmp = "$cacheDir/.tmp.$$.$pathHash.narinfo";
open INFO, ">$tmp" or die;
print INFO "$info" or die;
close INFO or die;
rename($tmp, $narInfoFile) or die "cannot rename $tmp to $narInfoFile: $!\n";
}
my $narInfo = parseNARInfo($storePath, readFile($narInfoFile));
$nar->{hash} = $narInfo->{fileHash};
$nar->{size} = $narInfo->{fileSize};
$nar->{narHash} = $narInfo->{narHash};
$nar->{narSize} = $narInfo->{narSize};
$nar->{url} = "$cacheURL/$narInfo->{url}";
warn "archive `$cacheDir/$narInfo->{url}' has gone missing!\n" unless -f "$cacheDir/$narInfo->{url}";
}
}
# Read all the old patches and propagate the useful ones. We use the
# file "all-patches" to keep track of all patches that have been
# generated in the past, so that patches are not lost if (for
# instance) a package temporarily disappears from the source channel,
# or if multiple instances of this script are running concurrently.
my (%dummy, %allPatches);
readManifest($allPatchesManifest, \%dummy, \%allPatches)
if $allPatchesManifest ne "" && -f $allPatchesManifest;
propagatePatches \%allPatches, \%narFiles, \%patches;
# Make the temporary manifest available.
writeManifest("$dstChannelPath/MANIFEST", \%narFiles, \%patches);