http: better error handling for EMFILE/ENFILE

Better to throw the error back to the client ASAP if we're
out-of-descriptors.  We will need to implement idle client
expiration for long-lived HTTP connections.

diff --git a/lib/PublicInbox/HTTP.pm b/lib/PublicInbox/HTTP.pm
index aaae7ab5c41424c10dd98a83cf7c56e68a3db2cc..17e7447545ca145a262bc055d60c338dcbcf050a 100644 (file)
--- a/lib/PublicInbox/HTTP.pm
+++ b/lib/PublicInbox/HTTP.pm
@@ -71,7 +71,10 @@ sub rbuf_process {
        return quit($self, 400) if $r == -1 || $env{HTTP_TRAILER};
        return $self->watch_read(1) if $r < 0; # incomplete
        $self->{rbuf} = substr($self->{rbuf}, $r);
+
        my $len = input_prepare($self, \%env);
+       defined $len or return write_err($self); # EMFILE/ENFILE
+
        $len ? event_read_input($self) : app_dispatch($self);
 }
 
@@ -116,7 +119,10 @@ sub app_dispatch ($) {
                $host =~ s/:(\d+)\z// and $env->{SERVER_PORT} = $1;
                $env->{SERVER_NAME} = $host;
        }
-       sysseek($env->{'psgi.input'}, 0, SEEK_SET) or die "input seek failed: $!";
+
+       sysseek($env->{'psgi.input'}, 0, SEEK_SET) or
+                       die "BUG: psgi.input seek failed: $!";
+
        my $res = Plack::Util::run_app($self->{httpd}->{app}, $env);
        eval {
                if (ref($res) eq 'CODE') {
@@ -222,13 +228,17 @@ sub input_prepare {
        if ($len) {
                $input = IO::File->new_tmpfile;
        } elsif (env_chunked($env)) {
-               $input = IO::File->new_tmpfile;
                $len = CHUNK_START;
+               $input = IO::File->new_tmpfile;
        }
+
+       # TODO: expire idle clients on ENFILE / EMFILE
+       return unless $input;
+
        binmode $input;
        $env->{'psgi.input'} = $input;
        $self->{env} = $env;
-       $self->{input_left} = $len;
+       $self->{input_left} = $len || 0;
 }
 
 sub env_chunked { ($_[0]->{HTTP_TRANSFER_ENCODING} || '') =~ /\bchunked\b/i }