[PATCH] httpd: fix SIGHUP by invalidating cache on reload

[Eric Wong <e@80x24.org>]

Eric Wong <e@80x24.org> wrote:
> I seem to recall HUP having some trouble with -httpd (and less
> so with nntpd/imapd); or at least that's what -daemon(8) manpage
> alludes to...

-------8<-------
Subject: [PATCH] httpd: fix SIGHUP by invalidating cache on reload

Since we require separate PublicInbox::HTTPD instances for each
listen socket address (in order to support {SERVER_<NAME|PORT>}
for PSGI env), the old cache needed to be invalidated on rare
app refreshes.

SIGHUP has always been broken in -httpd (but not -imapd or
-nntpd) due to this cache.

Update the daemon documentation and 5.10.1-ize some bits while
we're in the area.
---
 Documentation/public-inbox-daemon.pod |  8 +++++---
 script/public-inbox-httpd             |  6 ++++--
 t/httpd.t                             | 25 +++++++++++++++++++++++++
 3 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/Documentation/public-inbox-daemon.pod b/Documentation/public-inbox-daemon.pod
index ec210efa..f77fc3a9 100644
--- a/Documentation/public-inbox-daemon.pod
+++ b/Documentation/public-inbox-daemon.pod
@@ -5,13 +5,14 @@ public-inbox-daemon - common usage for public-inbox network daemons
 =head1 SYNOPSIS
 
 	public-inbox-httpd
+	public-inbox-imapd
 	public-inbox-nntpd
 
 =head1 DESCRIPTION
 
 This manual describes common options and behavior for
 public-inbox network daemons.  Network daemons for public-inbox
-provide read-only NNTP and HTTP access to public-inboxes.  Write
+provide read-only NNTP, IMAP and HTTP access to public-inboxes.  Write
 access to a public-inbox will never be required to run these.
 
 These daemons are implemented with a common core using
@@ -103,7 +104,7 @@ See L</UPGRADING> below.
 =item SIGHUP
 
 Reload config files associated with the process.
-(FIXME: not tested for -httpd, yet)
+(Note: broken for L<public-inbox-httpd(1)> only in E<lt>= 1.6)
 
 =item SIGTTIN
 
@@ -188,4 +189,5 @@ License: AGPL-3.0+ L<https://www.gnu.org/licenses/agpl-3.0.txt>
 
 =head1 SEE ALSO
 
-L<public-inbox-httpd(1)>, L<public-inbox-nntpd(1)>
+L<public-inbox-httpd(1)>, L<public-inbox-imapd(1)>,
+L<public-inbox-nntpd(1)>
diff --git a/script/public-inbox-httpd b/script/public-inbox-httpd
index b31b896d..7b0ec560 100755
--- a/script/public-inbox-httpd
+++ b/script/public-inbox-httpd
@@ -4,6 +4,7 @@
 #
 # Standalone HTTP server for public-inbox.
 use strict;
+use v5.10.1;
 use PublicInbox::Daemon;
 BEGIN {
 	for (qw(Plack::Builder Plack::Util)) {
@@ -14,7 +15,7 @@ BEGIN {
 	require PublicInbox::HTTPD;
 }
 
-my %httpds;
+my %httpds; # per-listen-FD mapping for HTTPD->{env}->{SERVER_<NAME|PORT>}
 my $app;
 my $refresh = sub {
 	if (@ARGV) {
@@ -37,12 +38,13 @@ my $refresh = sub {
 			sub { $www->call(@_) };
 		};
 	}
+	%httpds = (); # invalidate cache
 };
 
 PublicInbox::Daemon::run('0.0.0.0:8080', $refresh,
 	sub ($$$) { # post_accept
 		my ($client, $addr, $srv) = @_;
 		my $fd = fileno($srv);
-		my $h = $httpds{$fd} ||= PublicInbox::HTTPD->new($srv, $app);
+		my $h = $httpds{$fd} //= PublicInbox::HTTPD->new($srv, $app);
 		PublicInbox::HTTP->new($client, $addr, $h),
 	});
diff --git a/t/httpd.t b/t/httpd.t
index 0354a733..849f61bb 100644
--- a/t/httpd.t
+++ b/t/httpd.t
@@ -32,6 +32,10 @@ Date: Thu, 01 Jan 1970 06:06:06 +0000
 nntp
 EOF
 	};
+	my $i2 = create_inbox 'test-2', sub {
+		my ($im, $ibx) = @_;
+		$im->add(eml_load('t/plack-qp.eml')) or xbail '->add';
+	};
 	local $ENV{HOME} = $home;
 	my $cmd = [ '-init', $group, $inboxdir, 'http://example.com/', $addr ];
 	ok(run_script($cmd), 'init ran properly');
@@ -64,6 +68,27 @@ EOF
 			"$http_pfx/$group", "$tmpdir/dumb.git"),
 		0, 'clone successful');
 
+	# test config reload
+	my $cfg = "$home/.public-inbox/config";
+	open my $fh, '>>', $cfg or xbail "open: $!";
+	print $fh <<EOM or xbail "print $!";
+[publicinbox "test-2"]
+	inboxdir = $i2->{inboxdir}
+	address = test-2\@example.com
+	url = https://example.com/test-2
+EOM
+	close $fh or xbail "close $!";
+	$td->kill('HUP') or BAIL_OUT "failed to kill -httpd: $!";
+	tick; # wait for HUP to take effect
+	my $buf = do {
+		my $c2 = tcp_connect($sock);
+		$c2->write("GET /test-2/qp\@example.com/raw HTTP/1.0\r\n\r\n")
+					or xbail "c2 write: $!";
+		local $/;
+		<$c2>
+	};
+	like($buf, qr!\AHTTP/1\.0 200\b!s, 'got 200 after reload for test-2');
+
 	ok($td->kill, 'killed httpd');
 	$td->join;