uperl/Kafka-Librd - Githubissues

NAME Kafka::Librd - bindings for librdkafka

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 subscription set

subscription $tplist = $kafka->subscription

return current subscriptions. Subscription returned as a reference to
array of hashes with the following fields: "topic", "partition",
"offset", "metadata".

assign $err = $kafka->assign(\@tplist)

assign partitions to consume. @tplist is an array of hashes with "topic"
and "partition" fields set.

assignment $tplist = $kafka->assignment

return current assignment. Result returned in the same way as for
"subscription".

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.

commit $err = $kafka->commit(\@tplist, $async)

commit offsets to the broker. @tplist is an array of hashes with the
following keys: "topic", "partition", "offset", "metadata". If
@topic_partition_list is missing or undef, then current partition
assignment is used instead. If $async is 1, then method returns
immediately, if it is 0 or missing then method blocks until offsets are
committed.

commit_message $err = $kafka->commit_message($msg, $async)

commit message's offset for the message's partition. $async same as for
"commit".

committed $tplist = $kafka->committed(\@tplist, $timeout_ms)

retrieve committed offsets for topics and partitions specified in
@tplist, which is an array of hashes with "topic" and "partition"
fields. Returned $tplist contains a copy of the input list with added
"offset" fields.

position $tplist = $kafka->position(\@tplist)

retrieve current offsets for topics and partitions specified in @tplist,
which is an array of hashes with "topic" and "partition" fields.
Returned $tplist contains a copy of the input list with added "offset"
fields.

consumer_close $err = $kafka->consumer_close

close down the consumer

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

Return a topic object, that can be used to produce messages.

If an error occurs during creation of the topic, "undef" is returned. In
such case use "Kafka::Librd::Error::last_error" to obtain the
corresponding error code!

outq_len $len = $kafka->outq_len

return the current out queue length.

flush $kafka->flush($timeout_ms)

wait until all outstanding produce requests, et.al, are completed.

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 $status = $topic->produce($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.

The returned status is -1 in case of an error, otherwise 0. The error
code can be retrieved using the "Kafka::Librd::Error::last_error"
function.

destroy $topic->destroy

destroy topic handle

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

timestamp(\$tstype) return message timestamp (milliseconds since UNIX epoch)

The $tstype argument is optional, and if present, it should be a scalar
reference. It will be filled with one of the following values:

*   "Kafka::Librd::RD_KAFKA_TIMESTAMP_NOT_AVAILABLE"

*   "Kafka::Librd::RD_KAFKA_TIMESTAMP_CREATE_TIME"

*   "Kafka::Librd::RD_KAFKA_TIMESTAMP_LOG_APPEND_TIME"

Kafka::Librd::Error Kafka::Librd::Error::to_string my $error_message = Kafka::Librd::Error::to_string($err)

Convert an error code into a human-readable error description. Use this
for error codes returned by "Kafka::Librd::Error::last_error" and
Kafka::Librd::Message::err.

Kafka::Librd::Error::last_error my $err = Kafka::Librd::Error::last_error

Retrieve the last error state set by function calls "topic" and
"produce". This function should be called immediately after those
functions, since they store error information globally.

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

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

AUTHOR Original author Pavel Shaydo ""

Current maintainer Graham Ollis "<plicease@cpan.org>"

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.

uperl / Kafka-Librd

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