script/lei: handle SIGTSTP and SIGCONT

Sometimes it's useful to pause an expensive query or
refresh-mail-sync to do something else.  While lei-daemon and
lei/store can't be paused since they're shared across clients,
per-invocation WQ workers can be paused safely using the
unblockable SIGSTOP.

While we're at it, drop the ETOOMANYREFS hint since it
hasn't been a problem since we drastically reduced FD passing
early in development.

diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index f94bfa451c656491cd025c6c2674b4d35b414e21..2df1f326a63b7ff528262ed7bbf712dfb7486368 100644 (file)
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -1118,23 +1118,28 @@ sub dclose {
 sub event_step {
        my ($self) = @_;
        local %ENV = %{$self->{env}};
-       my $sock = $self->{sock};
        local $current_lei = $self;
        eval {
-               while (my @fds = $recv_cmd->($sock, my $buf, 4096)) {
+               my $buf;
+               while (my @fds = $recv_cmd->($self->{sock}, $buf, 4096)) {
                        if (scalar(@fds) == 1 && !defined($fds[0])) {
                                return if $! == EAGAIN;
                                next if $! == EINTR;
                                last if $! == ECONNRESET;
                                die "recvmsg: $!";
                        }
-                       for my $fd (@fds) {
-                               open my $rfh, '+<&=', $fd;
+                       for (@fds) { open my $rfh, '+<&=', $_ }
+               }
+               if ($buf eq '') {
+                       _drop_wq($self); # EOF, client disconnected
+                       dclose($self);
+               } elsif ($buf =~ /\A(STOP|CONT)\z/) {
+                       for my $wq (grep(defined, @$self{@WQ_KEYS})) {
+                               $wq->wq_kill($buf) or $wq->wq_kill_old($buf);
                        }
+               } else {
                        die "unrecognized client signal: $buf";
                }
-               _drop_wq($self); # EOF, client disconnected
-               dclose($self);
        };
        if (my $err = $@) {
                eval { $self->fail($err) };
@@ -1146,6 +1151,7 @@ sub event_step_init {
        my ($self) = @_;
        my $sock = $self->{sock} or return;
        $self->{-event_init_done} //= do { # persist til $ops done
+               $sock->blocking(0);
                $self->SUPER::new($sock, EPOLLIN|EPOLLET);
                $sock;
        };

diff --git a/script/lei b/script/lei
index 591013e3804ab6979f429e2aa00f6fba351cf26a..399296ba1a8d453597e93dc0cb9dfa9b7c99b916 100755 (executable)
--- a/script/lei
+++ b/script/lei
@@ -106,11 +106,10 @@ open my $dh, '<', '.' or die "open(.) $!";
 my $buf = join("\0", scalar(@ARGV), @ARGV);
 while (my ($k, $v) = each %ENV) { $buf .= "\0$k=$v" }
 $buf .= "\0\0";
-my $n = $send_cmd->($sock, [0, 1, 2, fileno($dh)], $buf, MSG_EOR);
-if (!$n) {
-       die "sendmsg: $! (check RLIMIT_NOFILE)\n" if $!{ETOOMANYREFS};
-       die "sendmsg: $!\n";
-}
+$send_cmd->($sock, [0, 1, 2, fileno($dh)], $buf, MSG_EOR) or die "sendmsg: $!";
+$SIG{TSTP} = sub { $send_cmd->($sock, [], 'STOP', MSG_EOR); kill 'STOP', $$ };
+$SIG{CONT} = sub { $send_cmd->($sock, [], 'CONT', MSG_EOR) };
+
 my $x_it_code = 0;
 while (1) {
        my (@fds) = $recv_cmd->($sock, my $buf, 4096 * 33);