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/*
* librdkafka - Apache Kafka C library
*
* Copyright (c) 2019, Magnus Edenhill
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/**
* Apache Kafka producer
* using the Kafka driver from librdkafka
* (https://github.com/edenhill/librdkafka)
*/
#include <iostream>
#include <string>
#include <cstdlib>
#include <cstdio>
#include <csignal>
#include <cstring>
#if _AIX
#include <unistd.h>
#endif
/*
* Typical include path in a real application would be
* #include <librdkafka/rdkafkacpp.h>
*/
#include "rdkafkacpp.h"
static volatile sig_atomic_t run = 1;
static void sigterm(int sig) {
run = 0;
}
class ExampleDeliveryReportCb : public RdKafka::DeliveryReportCb {
public:
void dr_cb(RdKafka::Message &message) {
/* If message.err() is non-zero the message delivery failed permanently
* for the message. */
if (message.err())
std::cerr << "% Message delivery failed: " << message.errstr()
<< std::endl;
else
std::cerr << "% Message delivered to topic " << message.topic_name()
<< " [" << message.partition() << "] at offset "
<< message.offset() << std::endl;
}
};
int main(int argc, char **argv) {
if (argc != 3) {
std::cerr << "Usage: " << argv[0] << " <brokers> <topic>\n";
exit(1);
}
std::string brokers = argv[1];
std::string topic = argv[2];
/*
* Create configuration object
*/
RdKafka::Conf *conf = RdKafka::Conf::create(RdKafka::Conf::CONF_GLOBAL);
std::string errstr;
/* Set bootstrap broker(s) as a comma-separated list of
* host or host:port (default port 9092).
* librdkafka will use the bootstrap brokers to acquire the full
* set of brokers from the cluster. */
if (conf->set("bootstrap.servers", brokers, errstr) !=
RdKafka::Conf::CONF_OK) {
std::cerr << errstr << std::endl;
exit(1);
}
signal(SIGINT, sigterm);
signal(SIGTERM, sigterm);
/* Set the delivery report callback.
* This callback will be called once per message to inform
* the application if delivery succeeded or failed.
* See dr_msg_cb() above.
* The callback is only triggered from ::poll() and ::flush().
*
* IMPORTANT:
* Make sure the DeliveryReport instance outlives the Producer object,
* either by putting it on the heap or as in this case as a stack variable
* that will NOT go out of scope for the duration of the Producer object.
*/
ExampleDeliveryReportCb ex_dr_cb;
if (conf->set("dr_cb", &ex_dr_cb, errstr) != RdKafka::Conf::CONF_OK) {
std::cerr << errstr << std::endl;
exit(1);
}
/*
* Create producer instance.
*/
RdKafka::Producer *producer = RdKafka::Producer::create(conf, errstr);
if (!producer) {
std::cerr << "Failed to create producer: " << errstr << std::endl;
exit(1);
}
delete conf;
/*
* Read messages from stdin and produce to broker.
*/
std::cout << "% Type message value and hit enter "
<< "to produce message." << std::endl;
for (std::string line; run && std::getline(std::cin, line);) {
if (line.empty()) {
producer->poll(0);
continue;
}
/*
* Send/Produce message.
* This is an asynchronous call, on success it will only
* enqueue the message on the internal producer queue.
* The actual delivery attempts to the broker are handled
* by background threads.
* The previously registered delivery report callback
* is used to signal back to the application when the message
* has been delivered (or failed permanently after retries).
*/
retry:
RdKafka::ErrorCode err = producer->produce(
/* Topic name */
topic,
/* Any Partition: the builtin partitioner will be
* used to assign the message to a topic based
* on the message key, or random partition if
* the key is not set. */
RdKafka::Topic::PARTITION_UA,
/* Make a copy of the value */
RdKafka::Producer::RK_MSG_COPY /* Copy payload */,
/* Value */
const_cast<char *>(line.c_str()), line.size(),
/* Key */
NULL, 0,
/* Timestamp (defaults to current time) */
0,
/* Message headers, if any */
NULL,
/* Per-message opaque value passed to
* delivery report */
NULL);
if (err != RdKafka::ERR_NO_ERROR) {
std::cerr << "% Failed to produce to topic " << topic << ": "
<< RdKafka::err2str(err) << std::endl;
if (err == RdKafka::ERR__QUEUE_FULL) {
/* If the internal queue is full, wait for
* messages to be delivered and then retry.
* The internal queue represents both
* messages to be sent and messages that have
* been sent or failed, awaiting their
* delivery report callback to be called.
*
* The internal queue is limited by the
* configuration property
* queue.buffering.max.messages and queue.buffering.max.kbytes */
producer->poll(1000 /*block for max 1000ms*/);
goto retry;
}
} else {
std::cerr << "% Enqueued message (" << line.size() << " bytes) "
<< "for topic " << topic << std::endl;
}
/* A producer application should continually serve
* the delivery report queue by calling poll()
* at frequent intervals.
* Either put the poll call in your main loop, or in a
* dedicated thread, or call it after every produce() call.
* Just make sure that poll() is still called
* during periods where you are not producing any messages
* to make sure previously produced messages have their
* delivery report callback served (and any other callbacks
* you register). */
producer->poll(0);
}
/* Wait for final messages to be delivered or fail.
* flush() is an abstraction over poll() which
* waits for all messages to be delivered. */
std::cerr << "% Flushing final messages..." << std::endl;
producer->flush(10 * 1000 /* wait for max 10 seconds */);
if (producer->outq_len() > 0)
std::cerr << "% " << producer->outq_len()
<< " message(s) were not delivered" << std::endl;
delete producer;
return 0;
}
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