From d78f50649a5545d66a61b5465ca7f5ce4be398ea Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Sat, 19 Sep 2020 09:37:14 +0000
Subject: gcf2: wire up read-only daemons and rm -gcf2 script

It seems easiest to have a singleton Gcf2Client client object
per daemon worker for all inboxes to use.  This reduces overall
FD usage from pipes.

The `public-inbox-gcf2' command + manpage are gone and a `$^X'
one-liner is used, instead.  This saves inodes for internal
commands and hopefully makes it easier to avoid mismatched
PERL5LIB include paths (as noticed during development :x).

We'll also make the existing cat-file process management
infrastructure more resilient to BOFHs on process killing
sprees (or in case our libgit2-based code fails on us).

(Rare) PublicInbox::WWW PSGI users NOT using public-inbox-httpd
won't automatically benefit from this change, and extra
configuration will be required (to be documented later).
---
 lib/PublicInbox/Git.pm | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

(limited to 'lib/PublicInbox/Git.pm')

diff --git a/lib/PublicInbox/Git.pm b/lib/PublicInbox/Git.pm
index 6bb82b6b..2323cecc 100644
--- a/lib/PublicInbox/Git.pm
+++ b/lib/PublicInbox/Git.pm
@@ -185,11 +185,12 @@ sub cat_async_step ($$) {
 	my $rbuf = delete($self->{cat_rbuf}) // \(my $new = '');
 	my ($bref, $oid, $type, $size);
 	my $head = my_readline($self->{in}, $rbuf);
+	# ->fail may be called via Gcf2Client.pm
 	if ($head =~ /^([0-9a-f]{40,}) (\S+) ([0-9]+)$/) {
 		($oid, $type, $size) = ($1, $2, $3 + 0);
 		$bref = my_read($self->{in}, $rbuf, $size + 1) or
-			fail($self, defined($bref) ? 'read EOF' : "read: $!");
-		chop($$bref) eq "\n" or fail($self, 'LF missing after blob');
+			$self->fail(defined($bref) ? 'read EOF' : "read: $!");
+		chop($$bref) eq "\n" or $self->fail('LF missing after blob');
 	} elsif ($head =~ s/ missing\n//s) {
 		$oid = $head;
 		# ref($req) indicates it's already been retried
@@ -201,7 +202,7 @@ sub cat_async_step ($$) {
 		$type = 'missing';
 		$oid = ref($req) ? $$req : $req if $oid eq '';
 	} else {
-		fail($self, "Unexpected result from async git cat-file: $head");
+		$self->fail("Unexpected result from async git cat-file: $head");
 	}
 	eval { $cb->($bref, $oid, $type, $size, $arg) };
 	$self->{cat_rbuf} = $rbuf if $$rbuf ne '';
@@ -304,10 +305,12 @@ sub check {
 
 sub _destroy {
 	my ($self, $rbuf, $in, $out, $pid, $err) = @_;
-	my $p = delete $self->{$pid} or return;
 	delete @$self{($rbuf, $in, $out)};
 	delete $self->{$err} if $err; # `err_c'
 
+	# GitAsyncCat::event_step may delete {pid}
+	my $p = delete $self->{$pid} or return;
+
 	# PublicInbox::DS may not be loaded
 	eval { PublicInbox::DS::dwaitpid($p, undef, undef) };
 	waitpid($p, 0) if $@; # wait synchronously if not in event loop
@@ -315,14 +318,21 @@ sub _destroy {
 
 sub cat_async_abort ($) {
 	my ($self) = @_;
-	my $inflight = delete $self->{inflight} or die 'BUG: not in async';
+	if (my $inflight = delete $self->{inflight}) {
+		while (@$inflight) {
+			my ($req, $cb, $arg) = splice(@$inflight, 0, 3);
+			$req =~ s/ .*//; # drop git_dir for Gcf2Client
+			eval { $cb->(undef, $req, undef, undef, $arg) };
+			warn "E: $req: $@ (in abort)\n" if $@;
+		}
+	}
 	cleanup($self);
 }
 
 sub fail {
 	my ($self, $msg) = @_;
-	$self->{inflight} ? cat_async_abort($self) : cleanup($self);
-	croak("git $self->{git_dir}: $msg");
+	cat_async_abort($self);
+	croak(ref($self) . ' ' . ($self->{git_dir} // '') . ": $msg");
 }
 
 sub popen {
@@ -352,6 +362,7 @@ sub cleanup {
 	!!($self->{pid} || $self->{pid_c});
 }
 
+
 # assuming a well-maintained repo, this should be a somewhat
 # accurate estimation of its size
 # TODO: show this in the WWW UI as a hint to potential cloners
@@ -397,7 +408,7 @@ sub pub_urls {
 sub cat_async_begin {
 	my ($self) = @_;
 	cleanup($self) if $self->alternates_changed;
-	batch_prepare($self);
+	$self->batch_prepare;
 	die 'BUG: already in async' if $self->{inflight};
 	$self->{inflight} = [];
 }
@@ -413,11 +424,9 @@ sub cat_async ($$$;$) {
 	push(@$inflight, $oid, $cb, $arg);
 }
 
-# this is safe to call inside $cb, but not guaranteed to enqueue
-# returns true if successful, undef if not.
 sub async_prefetch {
 	my ($self, $oid, $cb, $arg) = @_;
-	if (defined($self->{async_cat}) && (my $inflight = $self->{inflight})) {
+	if (my $inflight = $self->{inflight}) {
 		# we could use MAX_INFLIGHT here w/o the halving,
 		# but lets not allow one client to monopolize a git process
 		if (scalar(@$inflight) < int(MAX_INFLIGHT/2)) {
-- 
cgit v1.2.3-24-ge0c7