qspawn: implement psgi_qx

[public-inbox.git] / lib / PublicInbox / Qspawn.pm

diff --git a/lib/PublicInbox/Qspawn.pm b/lib/PublicInbox/Qspawn.pm
index b80dac1f3ca5bf829bfc3c04613a89155dc0c809..6859a8af31017d5d53d30a69475a48ae3fe06fcd 100644 (file)
--- a/lib/PublicInbox/Qspawn.pm
+++ b/lib/PublicInbox/Qspawn.pm
@@ -9,6 +9,7 @@ package PublicInbox::Qspawn;
 use strict;
 use warnings;
 use PublicInbox::Spawn qw(popen_rd);
+require Plack::Util;
 my $def_limiter;
 
 sub new ($$$;) {
@@ -60,33 +61,84 @@ sub start {
        }
 }
 
+sub _psgi_finish ($$) {
+       my ($self, $env) = @_;
+       my $err = $self->finish;
+       if ($err && !$env->{'qspawn.quiet'}) {
+               $err = join(' ', @{$self->{args}->[0]}).": $err\n";
+               $env->{'psgi.errors'}->print($err);
+       }
+}
+
+sub psgi_qx {
+       my ($self, $env, $limiter, $qx_cb) = @_;
+       my $qx = PublicInbox::Qspawn::Qx->new;
+       my $end = sub {
+               _psgi_finish($self, $env);
+               eval { $qx_cb->($qx) };
+               $qx = undef;
+       };
+       my $rpipe;
+       my $async = $env->{'pi-httpd.async'};
+       my $cb = sub {
+               my $r = sysread($rpipe, my $buf, 8192);
+               if ($async) {
+                       $async->async_pass($env->{'psgix.io'}, $qx, \$buf);
+               } elsif (defined $r) {
+                       $r ? $qx->write($buf) : $end->();
+               } else {
+                       return if $!{EAGAIN} || $!{EINTR}; # loop again
+                       $end->();
+               }
+       };
+       $limiter ||= $def_limiter ||= PublicInbox::Qspawn::Limiter->new(32);
+       $self->start($limiter, sub { # may run later, much later...
+               ($rpipe) = @_;
+               if ($async) {
+               # PublicInbox::HTTPD::Async->new($rpipe, $cb, $end)
+                       $async = $async->($rpipe, $cb, $end);
+               } else { # generic PSGI
+                       $cb->() while $qx;
+               }
+       });
+}
+
+# create a filter for "push"-based streaming PSGI writes used by HTTPD::Async
+sub filter_fh ($$) {
+       my ($fh, $filter) = @_;
+       Plack::Util::inline_object(
+               close => sub {
+                       $fh->write($filter->(undef));
+                       $fh->close;
+               },
+               write => sub {
+                       $fh->write($filter->($_[0]));
+               });
+}
+
 sub psgi_return {
        my ($self, $env, $limiter, $parse_hdr) = @_;
        my ($fh, $rpipe);
        my $end = sub {
-               if (my $err = $self->finish) {
-                       $err = join(' ', @{$self->{args}->[0]}).": $err\n";
-                       $env->{'psgi.errors'}->print($err);
-               }
+               _psgi_finish($self, $env);
                $fh->close if $fh; # async-only
        };
 
-       # Danga::Socket users, we queue up the read_enable callback to
-       # fire after pending writes are complete:
        my $buf = '';
        my $rd_hdr = sub {
                my $r = sysread($rpipe, $buf, 1024, length($buf));
                return if !defined($r) && ($!{EINTR} || $!{EAGAIN});
                $parse_hdr->($r, \$buf);
        };
-       my $res;
+       my $res = delete $env->{'qspawn.response'};
        my $async = $env->{'pi-httpd.async'};
        my $cb = sub {
                my $r = $rd_hdr->() or return;
                $rd_hdr = undef;
+               my $filter = delete $env->{'qspawn.filter'};
                if (scalar(@$r) == 3) { # error
                        if ($async) {
-                               $async->close; # calls rpipe->close
+                               $async->close; # calls rpipe->close and $end
                        } else {
                                $rpipe->close;
                                $end->();
@@ -94,26 +146,31 @@ sub psgi_return {
                        $res->($r);
                } elsif ($async) {
                        $fh = $res->($r); # scalar @$r == 2
+                       $fh = filter_fh($fh, $filter) if $filter;
                        $async->async_pass($env->{'psgix.io'}, $fh, \$buf);
                } else { # for synchronous PSGI servers
                        require PublicInbox::GetlineBody;
                        $r->[2] = PublicInbox::GetlineBody->new($rpipe, $end,
-                                                               $buf);
+                                                               $buf, $filter);
                        $res->($r);
                }
        };
        $limiter ||= $def_limiter ||= PublicInbox::Qspawn::Limiter->new(32);
+       my $start_cb = sub { # may run later, much later...
+               ($rpipe) = @_;
+               if ($async) {
+                       # PublicInbox::HTTPD::Async->new($rpipe, $cb, $end)
+                       $async = $async->($rpipe, $cb, $end);
+               } else { # generic PSGI
+                       $cb->() while $rd_hdr;
+               }
+       };
+
+       return $self->start($limiter, $start_cb) if $res;
+
        sub {
                ($res) = @_;
-               $self->start($limiter, sub { # may run later, much later...
-                       ($rpipe) = @_;
-                       if ($async) {
-                       # PublicInbox::HTTPD::Async->new($rpipe, $cb, $end)
-                               $async = $async->($rpipe, $cb, $end);
-                       } else { # generic PSGI
-                               $cb->() while $rd_hdr;
-                       }
-               });
+               $self->start($limiter, $start_cb);
        };
 }
 
@@ -131,4 +188,21 @@ sub new {
        }, $class;
 }
 
+# captures everything into a buffer and executes a callback when done
+package PublicInbox::Qspawn::Qx;
+use strict;
+use warnings;
+
+sub new {
+       my ($class) = @_;
+       my $buf = '';
+       bless \$buf, $class;
+}
+
+# called by PublicInbox::HTTPD::Async ($fh->write)
+sub write {
+       ${$_[0]} .= $_[1];
+       undef;
+}
+
 1;