lei_mirror: support --objstore and forkgroups

The {forkgroup} directive of grokmirror 2.x manifest.js.gz
can facilitate more space savings and improved pack performance
with pack.islands.

2 files changed, 192 insertions, 23 deletions

diff --git a/lib/PublicInbox/Fetch.pm b/lib/PublicInbox/Fetch.pm
index 06ed775f..3dbb0b55 100644
--- a/lib/PublicInbox/Fetch.pm
+++ b/lib/PublicInbox/Fetch.pm
@@ -15,19 +15,6 @@ use File::Temp ();
 
 sub new { bless {}, __PACKAGE__ }
 
-sub fetch_args ($$) {
-        my ($lei, $opt) = @_;
-        my @cmd; # (git --git-dir=...) to be added by caller
-        $opt->{$_} = $lei->{$_} for (0..2);
-        # we support "-c $key=$val" for arbitrary git config options
-        # e.g.: git -c http.proxy=socks5h://127.0.0.1:9050
-        push(@cmd, '-c', $_) for @{$lei->{opt}->{c} // []};
-        push @cmd, 'fetch';
-        push @cmd, '-q' if $lei->{opt}->{quiet};
-        push @cmd, '-v' if $lei->{opt}->{verbose};
-        @cmd;
-}
-
 sub remote_url ($$) {
         my ($lei, $dir) = @_;
         my $rn = $lei->{opt}->{'try-remote'} // [ 'origin', '_grokmirror' ];
@@ -205,7 +192,7 @@ EOM
                 if (-d $d) {
                         $fp2->[0] = get_fingerprint2($d) if $fp2;
                         $cmd = [ @$torsocks, 'git', "--git-dir=$d",
-                                fetch_args($lei, $opt) ];
+                               PublicInbox::LeiMirror::fetch_args($lei, $opt)];
                 } else {
                         my $e_uri = $ibx_uri->clone;
                         my ($epath) = ($d =~ m!(/git/[0-9]+\.git)\z!);
diff --git a/lib/PublicInbox/LeiMirror.pm b/lib/PublicInbox/LeiMirror.pm
index de4cdc22..799939b5 100644
--- a/lib/PublicInbox/LeiMirror.pm
+++ b/lib/PublicInbox/LeiMirror.pm
@@ -18,8 +18,10 @@ use PublicInbox::Config;
 use PublicInbox::Inbox;
 use PublicInbox::LeiCurl;
 use PublicInbox::OnDestroy;
+use Digest::SHA qw(sha256_hex);
 
 our $LIVE; # pid => callback
+my $update_ref_stdin = $ENV{GIT_CAN_UPDATE_REF_STDIN} // 1;
 
 sub _wq_done_wait { # dwaitpid callback (via wq_eof)
         my ($arg, $pid) = @_;
@@ -249,7 +251,173 @@ sub start_clone {
         reap_live() while keys(%$LIVE) >= $jobs;
         $self->{lei}->qerr("# @$cmd");
         return if $self->{dry_run};
-        $LIVE->{spawn($cmd, undef, $opt)} = [ \&reap_clone, $self, $cmd, $fini ]
+        $LIVE->{spawn($cmd, undef, $opt)} = [ \&reap_cmd, $self, $cmd, $fini ]
+}
+
+sub fetch_args ($$) {
+        my ($lei, $opt) = @_;
+        my @cmd; # (git --git-dir=...) to be added by caller
+        $opt->{$_} = $lei->{$_} for (0..2);
+        # we support "-c $key=$val" for arbitrary git config options
+        # e.g.: git -c http.proxy=socks5h://127.0.0.1:9050
+        push(@cmd, '-c', $_) for @{$lei->{opt}->{c} // []};
+        push @cmd, 'fetch';
+        push @cmd, '-q' if $lei->{opt}->{quiet} ||
+                        ($lei->{opt}->{jobs} // 1) > 1;
+        push @cmd, '-v' if $lei->{opt}->{verbose};
+        @cmd;
+}
+
+sub fgrp_update_old ($) { # for git <1.8.5
+        my ($fgrp) = @_;
+        my $cmd = [ 'git', "--git-dir=$fgrp->{cur_dst}",
+                fetch_args($fgrp->{lei}, my $opt = {}) ];
+        $fgrp->{lei}->qerr("# @$cmd");
+        $LIVE->{spawn($cmd, undef, $opt)} = [ \&reap_cmd, $fgrp, $cmd ];
+        my $jobs = $fgrp->{lei}->{opt}->{jobs} // 1;
+        reap_live() while keys(%$LIVE) >= $jobs;
+}
+
+sub upr { # feed `git update-ref --stdin -z' verbosely
+        my ($fgrp, $w, $op, $ref, $oid) = @_;
+        $fgrp->{lei}->qerr("# $op $ref $oid");
+        print $w "$op $ref\0$oid\0" or die "print(w): $!";
+}
+
+sub fgrp_update {
+        my ($fgrp) = @_;
+        my $srcfh = delete $fgrp->{srcfh} or return;
+        my $dstfh = delete $fgrp->{dstfh} or return;
+        seek($srcfh, SEEK_SET, 0) or die "seek(src): $!";
+        seek($dstfh, SEEK_SET, 0) or die "seek(dst): $!";
+        my %src = map { chomp; split(/\0/) } (<$srcfh>);
+        close $srcfh;
+        my %dst = map { chomp; split(/\0/) } (<$dstfh>);
+        close $dstfh;
+        pipe(my ($r, $w)) or die "pipe: $!";
+        my $cmd = [ 'git', "--git-dir=$fgrp->{cur_dst}",
+                qw(update-ref --stdin -z) ];
+        $fgrp->{lei}->qerr("# @$cmd");
+        my $opt = { 0 => $r, 1 => $fgrp->{lei}->{1}, 2 => $fgrp->{lei}->{2} };
+        my $pid = spawn($cmd, undef, $opt);
+        close $r or die "close(r): $!";
+        for my $ref (keys %dst) {
+                my $new = delete $src{$ref};
+                my $old = $dst{$ref};
+                if (defined $new) {
+                        upr($fgrp, $w, 'update', $ref, $new) if $new ne $old;
+                } else {
+                        upr($fgrp, $w, 'delete', $ref, $old);
+                }
+        }
+        while (my ($ref, $oid) = each %src) {
+                upr($fgrp, $w, 'create', $ref, $oid);
+        }
+        if (close($w)) { # git >= 1.8.5
+                $LIVE->{$pid} = [ \&reap_cmd, $fgrp, $cmd ];
+                my $jobs = $fgrp->{lei}->{opt}->{jobs} // 1;
+                reap_live() while keys(%$LIVE) >= $jobs;
+        } else { # git <1.8.5 w/o update-ref --stdin
+                warn "E: close(update-ref --stdin): $!\n";
+                $update_ref_stdin = 0;
+                waitpid($pid, 0) // die "waitpid(update-ref --stdin): $!";
+                fgrp_update_old($fgrp);
+        }
+}
+
+sub fgrp_fetched {
+        my ($fgrp) = @_;
+        return if $fgrp->{dry_run} || !$LIVE;
+        my $rn = $fgrp->{-remote};
+        my %opt = map { $_ => $fgrp->{lei}->{$_} } (0..2);
+        my $cmd = [ 'git', "--git-dir=$fgrp->{-osdir}",
+                        qw(pack-refs --all --prune) ];
+        $fgrp->{lei}->qerr("# @$cmd");
+        $LIVE->{spawn($cmd, undef, \%opt)} = [ \&reap_cmd, $fgrp, $cmd ];
+        my $jobs = $fgrp->{lei}->{opt}->{jobs} // 1;
+        reap_live() while keys(%$LIVE) >= $jobs;
+
+        $update_ref_stdin or return fgrp_update_old($fgrp);
+
+        my $update_ref = PublicInbox::OnDestroy->new($$, \&fgrp_update, $fgrp);
+
+        my $src = [ 'git', "--git-dir=$fgrp->{-osdir}", 'for-each-ref',
+                "--format=refs/%(refname:lstrip=3)%00%(objectname)",
+                "refs/remotes/$rn/" ];
+        open($fgrp->{srcfh}, '+>', undef) or die "open(src): $!";
+        $fgrp->{lei}->qerr("# @$src >SRC");
+        my $pid = spawn($src, undef, { %opt, 1 => $fgrp->{srcfh} });
+        $LIVE->{$pid} = [ \&reap_cmd, $fgrp, $src, $update_ref ];
+        reap_live() while keys(%$LIVE) >= $jobs;
+
+        my $dst = [ 'git', "--git-dir=$fgrp->{cur_dst}", 'for-each-ref',
+                '--format=%(refname)%00%(objectname)' ];
+        open($fgrp->{dstfh}, '+>', undef) or die "open(dst): $!";
+        $fgrp->{lei}->qerr("# @$dst >DST");
+        $pid = spawn($dst, undef, { %opt, 1 => $fgrp->{dstfh} });
+        $LIVE->{$pid} = [ \&reap_cmd, $fgrp, $dst, $update_ref ];
+        reap_live() while keys(%$LIVE) >= $jobs;
+}
+
+sub fgrp_fetch {
+        my ($fgrp, $pfx, $fini) = @_;
+        my $cmd = [ @$pfx, 'git', "--git-dir=$fgrp->{-osdir}",
+                        fetch_args($fgrp->{lei}, my $opt = {}),
+                        $fgrp->{-remote} ];
+        $fgrp->{-fini} = $fini;
+        my $jobs = $fgrp->{lei}->{opt}->{jobs} // 1;
+        reap_live() while keys(%$LIVE) >= $jobs;
+        $fgrp->{lei}->qerr("# @$cmd");
+        return if $fgrp->{dry_run};
+        my $fgrp_fini = PublicInbox::OnDestroy->new($$, \&fgrp_fetched, $fgrp);
+        my $pid = spawn($cmd, undef, $opt);
+        $LIVE->{$pid} = [ \&reap_cmd, $fgrp, $cmd, $fgrp_fini ];
+}
+
+# keep this idempotent for future use by public-inbox-fetch
+sub forkgroup_prep {
+        my ($self, $uri) = @_;
+        $self->{-ent} // return;
+        my $os = $self->{-objstore} // return;
+        my $fg = $self->{-ent}->{forkgroup} // return;
+        my $dir = "$os/$fg.git";
+        my @cmd = ('git', "--git-dir=$dir", 'config');
+        my $opt = +{ map { $_ => $self->{lei}->{$_} } (0..2) };
+        if (!-d $dir) {
+                PublicInbox::Import::init_bare($dir);
+                for ('repack.useDeltaIslands=true',
+                                'pack.island=refs/remotes/([^/]+)/') {
+                        run_die([@cmd, split(/=/, $_, 2)], undef, $opt);
+                }
+        }
+        my $key = $self->{-key} // die 'BUG: no -key';
+        my ($bn) = ($key =~ m{/([a-z0-9_,;=!\+\{\}\|][^/]*)(?:\.git)?\z}i);
+        my $rn = "$bn-".substr(sha256_hex($key), 0, 16);
+        for ("url=$uri", "fetch=+refs/*:refs/remotes/$rn/*") {
+                my @kv = split(/=/, $_, 2);
+                $kv[0] = "remote.$rn.$kv[0]";
+                run_die([@cmd, @kv], undef, $opt);
+        }
+        if (!-d $self->{cur_dst}) {
+                my $alt = File::Spec->rel2abs("$dir/objects");
+                PublicInbox::Import::init_bare($self->{cur_dst});
+                my $o = "$self->{cur_dst}/objects";
+                my $f = "$o/info/alternates";
+                my $l = File::Spec->abs2rel($alt, File::Spec->rel2abs($o));
+                open my $fh, '+>>', $f or die "open($f): $!";
+                seek($fh, SEEK_SET, 0) or die "seek($f): $!";
+                chomp(my @cur = <$fh>);
+                if (!grep(/\A\Q$l\E\z/, @cur)) {
+                        say $fh $l or die "say($f): $!";
+                }
+                close $fh or die "close($f): $!";
+                @cmd = ('git', "--git-dir=$self->{cur_dst}",
+                        qw(remote add --mirror=fetch origin), "$uri");
+                my $pid = spawn(\@cmd, undef, $opt);
+                waitpid($pid, 0) // die "waitpid(@cmd): $!";
+                die "E: @cmd: \$?=$?" if ($? && ($? >> 8) != 3);
+        }
+        bless { %$self, -osdir => $dir, -remote => $rn }, __PACKAGE__;
 }
 
 sub clone_v1 {
@@ -263,10 +431,15 @@ sub clone_v1 {
         my $dst = $self->{cur_dst} // $self->{dst};
         my $fini = PublicInbox::OnDestroy->new($$, \&v1_done, $self);
         my $cmd = [ @$pfx, clone_cmd($lei, my $opt = {}), "$uri", $dst ];
-        my $ref = $self->{-ent} ? $self->{-ent}->{reference} : undef;
-        defined($ref) && -e "$self->{dst}$ref" and
-                push @$cmd, '--reference', "$self->{dst}$ref";
-        start_clone($self, $cmd, $opt, $fini);
+        my $fgrp = forkgroup_prep($self, $uri);
+        if (!defined($fgrp) && defined($self->{-ent})) {
+                if (defined(my $ref = $self->{-ent}->{reference})) {
+                        -e "$self->{dst}$ref" and
+                                push @$cmd, '--reference', "$self->{dst}$ref";
+                }
+        }
+        $fgrp ? fgrp_fetch($fgrp, $pfx, $fini) :
+                start_clone($self, $cmd, $opt, $fini);
 
         if (!$self->{-is_epoch} && $lei->{opt}->{'inbox-config'} =~
                                 /\A(?:always|v1)\z/s) {
@@ -357,7 +530,7 @@ EOM
         }
 }
 
-sub reap_clone { # async, called via SIGCHLD
+sub reap_cmd { # async, called via SIGCHLD
         my ($self, $cmd) = @_;
         my $cerr = $?;
         $? = 0; # don't let it influence normal exit
@@ -377,8 +550,12 @@ sub v1_done { # called via OnDestroy
         }
         my $o = "$dst/objects";
         if (open(my $fh, '<', "$o/info/alternates")) {
+                my $base = File::Spec->rel2abs($o);
                 chomp(my @l = <$fh>);
-                for (@l) { $_ = File::Spec->abs2rel($_, $o)."\n" }
+                for (@l) {
+                        $_ = File::Spec->abs2rel($_, $base) if m!\A/!;
+                        $_ .= "\n";
+                }
                 my $f = File::Temp->new(TEMPLATE => '.XXXX', DIR => "$o/info");
                 print $f @l;
                 $f->flush or die "flush($f): $!";
@@ -417,7 +594,7 @@ sub reap_live {
         my $pid = waitpid(-1, 0) // die "waitpid(-1): $!";
         if (my $x = delete $LIVE->{$pid}) {
                 my $cb = shift @$x;
-                $cb->(@$x);
+                $cb->(@$x) if $cb;
         } else {
                 warn "reaped unknown PID=$pid ($?)\n";
         }
@@ -454,7 +631,7 @@ failed to extract epoch number from $src
                         }
                 }
                 if (!$want || $want->{$nr}) {
-                        my $etask = bless { %$task }, __PACKAGE__;
+                        my $etask = bless { %$task, -key => $key }, __PACKAGE__;
                         $etask->{-ent} = $ent; # may have {reference}
                         $etask->{cur_src} = $src;
                         $etask->{cur_dst} = $edst;
@@ -664,6 +841,7 @@ EOM
                                         die("BUG: no `$name' in manifest");
                         $task->{cur_src} = "$uri";
                         $task->{cur_dst} = $task->{dst};
+                        $task->{-key} = $name;
                         if ($n > 1) {
                                 $task->{cur_dst} .= $name;
                                 $task->{cur_src} .= $name;
@@ -702,6 +880,10 @@ sub do_mirror { # via wq_io_do or public-inbox-clone
                 $ic =~ /\A(?:v1|v2|always|never)\z/s or die <<"";
 --inbox-config must be one of `always', `v2', `v1', or `never'
 
+                if (defined(my $os = $lei->{opt}->{objstore})) {
+                        $os = 'objstore' if $os eq ''; # --objstore w/o args
+                        $self->{-objstore} = "$self->{dst}/$os";
+                }
                 local $LIVE;
                 my $iv = $lei->{opt}->{'inbox-version'} //
                         return start_clone_url($self);