| CC: | Ray Ferguson <Ray.Ferguson [...] cdw.com> |
| Subject: | Net-HTTP 6.06 intermittent death in Net::HTTP::Methods sub my_readline() (solved) |
| Date: | Wed, 26 Jun 2013 15:46:21 +0000 |
| To: | "bug-Net-HTTP [...] rt.cpan.org" <bug-Net-HTTP [...] rt.cpan.org> |
| From: | Ray Ferguson <Ray.Ferguson [...] cdw.com> |
Description:
Net::HTTP::Methods from Net-HTTP 6.06 dies intermittently with:
Status read failed: No such file or directory at …/perl/vendor/lib/Net/HTTP/Methods.pm line 265.
Cause:
IO::Socket::SSL object can reject the read request with an error of either "SSL wants a read first" or "SSL wants a write first." This is apparently some overhead of SSL where it wants a read/write before allowing you to read/write in some cases. It's described somewhat (but not much) better under errstr() in the latest IO::Socket::SSL perldoc.
Reproducing:
I'm not sure how hard this is to reproduce since triggers are unknown. I'm accessing cloud based SOAP via SOAP::WSDL over https from a busy server and it occurs maybe one out of a dozen times. It seems to correlate with SSL taking an extra bit of time to setup the connection when something in the chain is busier or has a little latency. Thus far, I've only seen SSL_WANT_READ, and it clears immediately on the next redo READ, but there seems to be no harm in preparing for SSL_WANT_WRITE in the patch as well.
Patch:
--- broken/Net/HTTP/Methods.pm 2013-03-10 23:35:42.000000000 -0500
+++ fixed/Net/HTTP/Methods.pm 2013-06-26 10:12:37.205639200 -0500
@@ -243,40 +243,41 @@
sub my_readline {
my $self = shift;
my $what = shift;
for (${*$self}{'http_buf'}) {
my $max_line_length = ${*$self}{'http_max_line_length'};
my $pos;
while (1) {
# find line ending
$pos = index($_, "\012");
last if $pos >= 0;
die "$what line too long (limit is $max_line_length)"
if $max_line_length && length($_) > $max_line_length;
# need to read more data to find a line ending
READ:
{
die "read timeout" unless $self->can_read;
my $n = $self->sysread($_, 1024, length);
unless (defined $n) {
redo READ if $!{EINTR} || $!{EAGAIN};
+ redo READ if ( $self->isa('IO::Socket::SSL') && $self->errstr() =~ /^SSL wants a (?:read|write) first$/ );
# if we have already accumulated some data let's at least
# return that as a line
die "$what read failed: $!" unless length;
}
unless ($n) {
return undef unless length;
return substr($_, 0, length, "");
}
}
}
die "$what line too long ($pos; limit is $max_line_length)"
if $max_line_length && $pos > $max_line_length;
my $line = substr($_, 0, $pos+1, "");
$line =~ s/(\015?\012)\z// || die "Assert";
return wantarray ? ($line, $1) : $line;
}
}
Thanks for your time and your code.
--
Raymond Ferguson
Integrated Applications Engineer | CDW