1 # Copyright (C) 2016-2018 all contributors <meta@public-inbox.org>
2 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
4 # Limits the number of processes spawned
5 # This does not depend on Danga::Socket or any other external
6 # scheduling mechanism, you just need to call start and finish
8 package PublicInbox::Qspawn;
11 use PublicInbox::Spawn qw(popen_rd);
16 my ($class, $cmd, $env, $opt) = @_;
17 bless { args => [ $cmd, $env, $opt ] }, $class;
24 ($self->{rpipe}, $self->{pid}) = popen_rd(@{$self->{args}});
25 if (defined $self->{pid}) {
26 $self->{limiter}->{running}++;
30 $cb->($self->{rpipe});
35 my $limiter = $self->{limiter};
37 if (delete $self->{rpipe}) {
38 my $pid = delete $self->{pid};
39 $self->{err} = $pid == waitpid($pid, 0) ? $? :
40 "PID:$pid still running?";
41 $running = --$limiter->{running};
44 # limiter->{max} may change dynamically
45 if (($running || $limiter->{running}) < $limiter->{max}) {
46 if (my $next = shift @{$limiter->{run_queue}}) {
54 my ($self, $limiter, $cb) = @_;
55 $self->{limiter} = $limiter;
57 if ($limiter->{running} < $limiter->{max}) {
58 _do_spawn($self, $cb);
60 push @{$limiter->{run_queue}}, [ $self, $cb ];
64 sub _psgi_finish ($$) {
65 my ($self, $env) = @_;
66 my $err = $self->finish;
67 if ($err && !$env->{'qspawn.quiet'}) {
68 $err = join(' ', @{$self->{args}->[0]}).": $err\n";
69 $env->{'psgi.errors'}->print($err);
74 my ($self, $env, $limiter, $qx_cb) = @_;
75 my $qx = PublicInbox::Qspawn::Qx->new;
77 _psgi_finish($self, $env);
78 eval { $qx_cb->($qx) };
82 my $async = $env->{'pi-httpd.async'};
84 my $r = sysread($rpipe, my $buf, 8192);
86 $async->async_pass($env->{'psgix.io'}, $qx, \$buf);
87 } elsif (defined $r) {
88 $r ? $qx->write($buf) : $end->();
90 return if $!{EAGAIN} || $!{EINTR}; # loop again
94 $limiter ||= $def_limiter ||= PublicInbox::Qspawn::Limiter->new(32);
95 $self->start($limiter, sub { # may run later, much later...
98 # PublicInbox::HTTPD::Async->new($rpipe, $cb, $end)
99 $async = $async->($rpipe, $cb, $end);
100 } else { # generic PSGI
106 # create a filter for "push"-based streaming PSGI writes used by HTTPD::Async
108 my ($fh, $filter) = @_;
109 Plack::Util::inline_object(
111 $fh->write($filter->(undef));
115 $fh->write($filter->($_[0]));
120 my ($self, $env, $limiter, $parse_hdr) = @_;
123 _psgi_finish($self, $env);
124 $fh->close if $fh; # async-only
129 my $r = sysread($rpipe, $buf, 1024, length($buf));
130 return if !defined($r) && ($!{EINTR} || $!{EAGAIN});
131 $parse_hdr->($r, \$buf);
133 my $res = delete $env->{'qspawn.response'};
134 my $async = $env->{'pi-httpd.async'};
136 my $r = $rd_hdr->() or return;
138 my $filter = delete $env->{'qspawn.filter'};
139 if (scalar(@$r) == 3) { # error
141 $async->close; # calls rpipe->close and $end
148 $fh = $res->($r); # scalar @$r == 2
149 $fh = filter_fh($fh, $filter) if $filter;
150 $async->async_pass($env->{'psgix.io'}, $fh, \$buf);
151 } else { # for synchronous PSGI servers
152 require PublicInbox::GetlineBody;
153 $r->[2] = PublicInbox::GetlineBody->new($rpipe, $end,
158 $limiter ||= $def_limiter ||= PublicInbox::Qspawn::Limiter->new(32);
159 my $start_cb = sub { # may run later, much later...
162 # PublicInbox::HTTPD::Async->new($rpipe, $cb, $end)
163 $async = $async->($rpipe, $cb, $end);
164 } else { # generic PSGI
165 $cb->() while $rd_hdr;
169 return $self->start($limiter, $start_cb) if $res;
173 $self->start($limiter, $start_cb);
177 package PublicInbox::Qspawn::Limiter;
182 my ($class, $max) = @_;
184 # 32 is same as the git-daemon connection limit
191 # captures everything into a buffer and executes a callback when done
192 package PublicInbox::Qspawn::Qx;
202 # called by PublicInbox::HTTPD::Async ($fh->write)