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Connect to Kafka server over SSL

by cLive ;-) (Prior)
on Jan 14, 2020 at 02:05 UTC ( #11111391=perlquestion: print w/replies, xml ) Need Help??

cLive ;-) has asked for the wisdom of the Perl Monks concerning the following question:

I have a requirement to connect to a Kafka server over SSL. I have the certs, private key, and password, but I can't work out how to even test a connection. Looking at the Kafka modules, they use Socket to create the connection, and the Kafka modules don't support SSL.

I've started playing with IO::Socket::SSL to try to connect to the server, but I think I'll have to work out how to do this at the lower level Socket interface, even if I manage to connect using IO::Socket::SSL, because of how Kafka::IO is written. I know very little about socket coding, nor why the decision was made to use Socket over IO::Socket so this feels like a very steep learning curve. So far, I've managed to create the socket, and I can send data to the server, but I'm guessing the server thinks it's just gibberish, because it closes the socket straight away. Or, possibly, I'm not doing whatever it is I need to do with the password to get a valid response.

Does anyone have any pointers that could get me going in the right direction. I did drag out my old copy of Stein's Network programming with Perl, but I don't see any references to SSL in it.

I get no errors when running this at debug level 3:

my $socket = IO::Socket::SSL->new( PeerAddr => $host, PeerPort => 9094, SSL_verify_mode => SSL_VERIFY_NONE, SSL_key_file => './key.pem', SSL_cert_file => './cert.pem', ) or die "failed to connect: $SSL_ERROR"

but that doesn't include using the password (I'm not sure whether that's for the SSL level or Kafka level ATM). Is there something I can print to the socket to get metadata from the server?

I tried looking for info on the raw socket commends that Kafka uses, but I'm only finding API docs right now :/

All pointers welcomed...


Got it working with Net::Kafka after following the pointers below. For future reference for those that need it, here's the code I used:
use v5.22; use strictures 2; use JSON::XS qw(decode_json); use Data::Dumper 'Dumper'; use Net::Kafka::Consumer; my $consumer = Net::Kafka::Consumer->new( 'bootstrap.servers' => ',,server', '' => 'my_consumer_group', 'security.protocol' => 'SSL', 'ssl.keystore.location' => '/path/to/kafka.client.keystore.p12', 'ssl.keystore.password' => 'password', 'ssl.key.password' => 'password', error_cb => sub { my ($self, $err, $msg) = @_; warn Dumper({ ERR => $err, MSG => $msg }); }, ); # see for all options $consumer->subscribe( [ "my_topic" ] ); warn Dumper({ consumer => $consumer }); while (1) { my $msg = $consumer->poll(1000); if ($msg) { if ( my $err = $msg->err ) { say "Error: ", Net::Kafka::Error::to_string($err); } else { say Dumper({ PAYLOAD => decode_json $msg->payload }); } } }
The module is sparsely documented, so I ended up doing a little hit and miss testing to get here.

Replies are listed 'Best First'.
Re: Connect to Kafka server over SSL
by Anonymous Monk on Jan 14, 2020 at 02:22 UTC
      Thanks - I'll take a look in the morning with a clear head.
Re: Connect to Kafka server over SSL
by talexb (Canon) on Jan 14, 2020 at 18:40 UTC

    Ooh -- this is something I was looking into recently. Looking forward to hearing how this turns out.

    Alex / talexb / Toronto

    Thanks PJ. We owe you so much. Groklaw -- RIP -- 2003 to 2013.

      Got it working - see original post update
      It might be a week or so, but I will update here when implemented. It looks like the Debezium stream I'm meant to be attaching to is down on the dev server ATM, so I have to wait for someone on the other side of the world to bring it back up tomorrow.

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