NAME

Kafka::Librd - bindings for librdkafka

VERSION

This document describes Kafka::Librd version 0.05

SYNOPSIS

    use Kafka::Librd;

    my $kafka = Kafka::Librd->new(
        Kafka::Librd::RD_KAFKA_CONSUMER,
        {
            "group.id" => 'consumer_id',
        },
    );
    $kafka->brokers_add('server1:9092,server2:9092');
    $kafka->subscribe( \@topics );
    while (1) {
        my $msg = $kafka->consumer_poll(1000);
        if ($msg) {
            if ( $msg->err ) {
                say "Error: ", Kafka::Librd::Error::to_string($err);
            }
            else {
                say $msg->payload;
            }
        }
    }

DESCRIPTION

This module provides perl bindings for librdkafka.

METHODS

new

    $kafka = $class->new($type, \%config)

Create a new instance. $type can be either RD_KAFKA_CONSUMER or RD_KAFKA_PRODUCER. Config is a hash with configuration parameters as described in https://github.com/edenhill/librdkafka/blob/master/CONFIGURATION.md, additionally it may include default_topic_config key, with a hash containing default topic configuration properties.

brokers_add

    $cnt = $kafka->brokers_add($brokers)

add one or more brokers to the list of initial bootstrap brokers. $brokers is a comma separated list of brokers in the format [proto://]host[:port].

subscribe

    $err = $kafka->subscribe(\@topics)

subscribe to the list of topics using balanced consumer groups.

unsubscribe

    $err = $kafka->unsubscribe

unsubscribe from the current subsctiption set

consumer_poll

    $msg = $kafka->consumer_poll($timeout_ms)

poll for messages or events. If any message or event received, returns "Kafka::Librd::Message" object. If <$msg-err>> for returned object is zero (RD_KAFKA_RESP_ERR_NO_ERROR), then it is a proper message, otherwise it is an event or an error.

consumer_close

    $err = $kafka->consumer_close

close down the consumer

topic

    $topic = $kafka->topic($name, \%config)

return a "Kafka::Librd::Topic"topic object, that can be used to produce messages

outq_len

    $len = $kafka->outq_len

return the current out queue length.

destroy

    $kafka->destroy

destroy kafka handle

dump

    $kafka->dump

dump internal state of kafka handle to stdout, only useful for debugging

Kafka::Librd::Topic

This class maps to rd_kafka_topic_t structure from librdkafka and represents topic. It should be created with "topic" method of Kafka::Librd object. It provides the following method:

produce

    $err = $topic->produce($partition, $msgflags, $payload, $key)

produce a message for the topic. $msgflags can be RD_KAFKA_MSG_F_BLOCK in the future, but currently it should be set to 0, RD_KAFKA_MSG_F_COPY and RD_KAFKA_MSG_F_FREE must not be used, internally RD_KAFKA_MSG_F_COPY is always set.

Kafka::Librd::Message

This class maps to rd_kafka_message_t structure from librdkafka and represents message or event. Objects of this class have the following methods:

err

return error code from the message

topic

return topic name

partition

return partition number

offset

return offset. Note, that the value is truncated to 32 bit if your perl doesn't support 64 bit integers.

key

return message key

payload

return message payload

CAVEATS

Module is in early stage of development, only basic functionality is implemented.

Message offset is truncated to 32 bit if perl compiled without support for 64 bit integers.

SEE ALSO

https://github.com/edenhill/librdkafka

BUGS

Please report any bugs or feature requests via GitHub bug tracker at http://github.com/trinitum/perl-Kafka-Librd/issues.

AUTHOR

Pavel Shaydo <zwon at cpan.org>

LICENSE AND COPYRIGHT

Copyright (C) 2016 Pavel Shaydo

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.

cpanm Kafka::Librd

perl -MCPAN -e shell
install Kafka::Librd