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authorEric Wong <e@80x24.org>2021-10-16 01:00:54 +0000
committerEric Wong <e@80x24.org>2021-10-16 01:42:49 +0000
commita1a8cbab22adec879f97dccd9acfd0c5b2492ba9 (patch)
tree78647cecb223c4116634fee548de9c075ef574f3
parentf64adbd5e3c35197c1915bca108cdcd81f74f708 (diff)
downloadpublic-inbox-a1a8cbab22adec879f97dccd9acfd0c5b2492ba9.tar.gz
It's needlessly complex and O(n), so it doesn't scale well to a
high number of clients nor is it easy-to-scale with the data
structures available to us in pure Perl.

In any case, I see no evidence of either -imapd nor -nntpd
experiencing high connection loads on public-facing sites.
-httpd has never had its own timer-based expiration, either.

Fwiw, public-inbox.org itself has been running a public-facing
HTTP/HTTPS server with no userspace idle client expiration for
the past 8 years or with no ill effect.  Clients can come and go
as they wish, and SO_KEEPALIVE takes care of truly broken
connections if they're gone for ~2 hours.

Internet connections drop all time, so it should be harmless to
drop connections w/o warning since both NNTP and IMAP protocols
have well-defined semantics for determining if a message was
truncated (as does HTTP/1.1+).
-rw-r--r--lib/PublicInbox/DS.pm37
-rw-r--r--lib/PublicInbox/Daemon.pm8
-rw-r--r--lib/PublicInbox/HTTP.pm5
-rw-r--r--lib/PublicInbox/IMAP.pm17
-rw-r--r--lib/PublicInbox/NNTP.pm12
5 files changed, 13 insertions, 66 deletions
diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index 9cca02d7..bf8c4466 100644
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -37,9 +37,7 @@ our @EXPORT_OK = qw(now msg_more dwaitpid add_timer add_uniq_timer);
 my %Stack;
 my $nextq; # queue for next_tick
 my $wait_pids; # list of [ pid, callback, callback_arg ]
-my $EXPMAP; # fd -> idle_time
-our $EXPTIME = 180; # 3 minutes
-my ($reap_armed);
+my $reap_armed;
 my $ToClose; # sockets to close when event loop is done
 our (
      %DescriptorMap,             # fd (num) -> PublicInbox::DS object
@@ -76,7 +74,6 @@ sub Reset {
                 # we may be iterating inside one of these on our stack
                 my @q = delete @Stack{keys %Stack};
                 for my $q (@q) { @$q = () }
-                $EXPMAP = undef;
                 $wait_pids = $nextq = $ToClose = undef;
                 $ep_io = undef; # closes real $Epoll FD
                 $Epoll = undef; # may call DSKQXS::DESTROY
@@ -251,9 +248,6 @@ sub PostEventLoop () {
                 $ToClose = undef; # will be autovivified on push
                 @$close_now = map { fileno($_) } @$close_now;
 
-                # order matters, destroy expiry times, first:
-                delete @$EXPMAP{@$close_now};
-
                 # ->DESTROY methods may populate ToClose
                 delete @DescriptorMap{@$close_now};
         }
@@ -655,35 +649,6 @@ sub dwaitpid ($;$$) {
         }
 }
 
-sub expire_old () {
-        my $cur = $EXPMAP or return;
-        $EXPMAP = undef;
-        my $old = now() - $EXPTIME;
-        while (my ($fd, $idle_at) = each %$cur) {
-                if ($idle_at < $old) {
-                        my $ds_obj = $DescriptorMap{$fd};
-                        $EXPMAP->{$fd} = $idle_at if !$ds_obj->shutdn;
-                } else {
-                        $EXPMAP->{$fd} = $idle_at;
-                }
-        }
-        add_uniq_timer('expire', 60, \&expire_old) if $EXPMAP;
-}
-
-sub update_idle_time {
-        my ($self) = @_;
-        my $sock = $self->{sock} or return;
-        $EXPMAP->{fileno($sock)} = now();
-        add_uniq_timer('expire', 60, \&expire_old);
-}
-
-sub not_idle_long {
-        my ($self, $now) = @_;
-        my $sock = $self->{sock} or return;
-        my $idle_at = $EXPMAP->{fileno($sock)} or return;
-        ($idle_at + $EXPTIME) > $now;
-}
-
 1;
 
 =head1 AUTHORS (Danga::Socket)
diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm
index 90b77412..50523586 100644
--- a/lib/PublicInbox/Daemon.pm
+++ b/lib/PublicInbox/Daemon.pm
@@ -271,13 +271,11 @@ sub worker_quit { # $_[0] = signal name or number (unused)
                 my ($dmap, undef) = @_;
                 my $n = 0;
                 my $now = now();
-
-                foreach my $s (values %$dmap) {
+                for my $s (values %$dmap) {
                         $s->can('busy') or next;
-                        if ($s->busy($now)) {
+                        if ($s->busy) {
                                 ++$n;
-                        } else {
-                                # close as much as possible, early as possible
+                        } else { # close as much as possible, early as possible
                                 $s->close;
                         }
                 }
diff --git a/lib/PublicInbox/HTTP.pm b/lib/PublicInbox/HTTP.pm
index 8a89dd73..8057481d 100644
--- a/lib/PublicInbox/HTTP.pm
+++ b/lib/PublicInbox/HTTP.pm
@@ -459,10 +459,9 @@ sub close {
         $self->SUPER::close; # PublicInbox::DS::close
 }
 
-# for graceful shutdown in PublicInbox::Daemon:
-sub busy () {
+sub busy { # for graceful shutdown in PublicInbox::Daemon:
         my ($self) = @_;
-        ($self->{rbuf} || exists($self->{env}) || $self->{wbuf});
+        defined($self->{rbuf}) || exists($self->{env}) || defined($self->{wbuf})
 }
 
 # runs $cb on the next iteration of the event loop at earliest
diff --git a/lib/PublicInbox/IMAP.pm b/lib/PublicInbox/IMAP.pm
index bc34f4fe..41bcf9af 100644
--- a/lib/PublicInbox/IMAP.pm
+++ b/lib/PublicInbox/IMAP.pm
@@ -99,9 +99,6 @@ undef %FETCH_NEED;
 my $valid_range = '[0-9]+|[0-9]+:[0-9]+|[0-9]+:\*';
 $valid_range = qr/\A(?:$valid_range)(?:,(?:$valid_range))*\z/;
 
-# RFC 3501 5.4. Autologout Timer needs to be >= 30min
-$PublicInbox::DS::EXPTIME = 60 * 30;
-
 sub greet ($) {
         my ($self) = @_;
         my $capa = capa($self);
@@ -124,7 +121,6 @@ sub new ($$$) {
         } else {
                 greet($self);
         }
-        $self->update_idle_time;
         $self;
 }
 
@@ -323,7 +319,6 @@ sub idle_tick_all {
         $IDLERS = undef;
         for my $i (values %$old) {
                 next if ($i->{wbuf} || !exists($i->{-idle_tag}));
-                $i->update_idle_time or next;
                 $IDLERS->{fileno($i->{sock})} = $i;
                 $i->write(\"* OK Still here\r\n");
         }
@@ -1226,8 +1221,6 @@ sub long_step {
                 out($self, " deferred[$fd] aborted - %0.6f", $elapsed);
                 $self->close;
         } elsif ($more) { # $self->{wbuf}:
-                $self->update_idle_time;
-
                 # control passed to ibx_async_cat if $more == \undef
                 requeue_once($self) if !ref($more);
         } else { # all done!
@@ -1269,7 +1262,6 @@ sub event_step {
 
         return unless $self->flush_write && $self->{sock} && !$self->{long_cb};
 
-        $self->update_idle_time;
         # only read more requests if we've drained the write buffer,
         # otherwise we can be buffering infinitely w/o backpressure
 
@@ -1295,7 +1287,6 @@ sub event_step {
 
         return $self->close if $r < 0;
         $self->rbuf_idle($rbuf);
-        $self->update_idle_time;
 
         # maybe there's more pipelined data, or we'll have
         # to register it for socket-readiness notifications
@@ -1334,14 +1325,14 @@ sub cmd_starttls ($$) {
         undef;
 }
 
-# for graceful shutdown in PublicInbox::Daemon:
-sub busy {
-        my ($self, $now) = @_;
+sub busy { # for graceful shutdown in PublicInbox::Daemon:
+        my ($self) = @_;
         if (defined($self->{-idle_tag})) {
                 $self->write(\"* BYE server shutting down\r\n");
                 return; # not busy anymore
         }
-        ($self->{rbuf} || $self->{wbuf} || $self->not_idle_long($now));
+        defined($self->{rbuf}) || defined($self->{wbuf}) ||
+                !$self->write(\"* BYE server shutting down\r\n");
 }
 
 sub close {
diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index aa019368..b36722d7 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -65,7 +65,6 @@ sub new ($$$) {
         } else {
                 greet($self);
         }
-        $self->update_idle_time;
         $self;
 }
 
@@ -651,8 +650,6 @@ sub long_step {
                 out($self, " deferred[$fd] aborted - %0.6f", $elapsed);
                 $self->close;
         } elsif ($more) { # $self->{wbuf}:
-                $self->update_idle_time;
-
                 # COMPRESS users all share the same DEFLATE context.
                 # Flush it here to ensure clients don't see
                 # each other's data
@@ -1050,7 +1047,6 @@ sub event_step {
 
         return unless $self->flush_write && $self->{sock} && !$self->{long_cb};
 
-        $self->update_idle_time;
         # only read more requests if we've drained the write buffer,
         # otherwise we can be buffering infinitely w/o backpressure
 
@@ -1072,17 +1068,15 @@ sub event_step {
         out($self, "[$fd] %s - %0.6f$pending", $line, now() - $t0);
         return $self->close if $r < 0;
         $self->rbuf_idle($rbuf);
-        $self->update_idle_time;
 
         # maybe there's more pipelined data, or we'll have
         # to register it for socket-readiness notifications
         $self->requeue unless $pending;
 }
 
-# for graceful shutdown in PublicInbox::Daemon:
-sub busy {
-        my ($self, $now) = @_;
-        ($self->{rbuf} || $self->{wbuf} || $self->not_idle_long($now));
+sub busy { # for graceful shutdown in PublicInbox::Daemon:
+        my ($self) = @_;
+        defined($self->{rbuf}) || defined($self->{wbuf})
 }
 
 1;