例子
#include "rdkafkacpp.h"
#include <chrono>
#include <time.h>
#include <sstream>
#include <iomanip>
#include <iostream>
void HandleMessage(RdKafka::Message &message, void *opaque)
{
switch (message.err()) {
case RdKafka::ERR__TIMED_OUT:
std::cout << "RdKafka::ERR__TIMED_OUT" << std::endl;
break;
case RdKafka::ERR_NO_ERROR:
RdKafka::MessageTimestamp ts;
ts = message.timestamp();
if (ts.type != RdKafka::MessageTimestamp::MSG_TIMESTAMP_NOT_AVAILABLE) {
std::string timeprefix;
if (ts.type == RdKafka::MessageTimestamp::MSG_TIMESTAMP_CREATE_TIME) {
timeprefix = "created time";
}
else if (ts.type == RdKafka::MessageTimestamp::MSG_TIMESTAMP_LOG_APPEND_TIME) {
timeprefix = "log append time";
}
unsigned long long milli = ts.timestamp + (unsigned long long)8 * 60 * 60 * 1000;//此处转化为东八区北京时间,如果是其它时区需要按需求修改
auto mTime = std::chrono::milliseconds(milli);
auto tp = std::chrono::time_point<std::chrono::system_clock, std::chrono::milliseconds>(mTime);
auto tt = std::chrono::system_clock::to_time_t(tp);
tm timeinfo;
::gmtime_s(&timeinfo, &tt);
char s[60]{ 0 };
::sprintf(s, "%04d-%02d-%02d %02d:%02d:%02d", timeinfo.tm_year + 1900, timeinfo.tm_mon + 1, timeinfo.tm_mday, timeinfo.tm_hour, timeinfo.tm_min, timeinfo.tm_sec);
std::cout << "接收到消息:TimeStamp" << timeprefix << " " << s << std::endl;
}
std::cout << message.topic_name() << " offset" << message.offset() << " partion " << message.partition() << " message: " << reinterpret_cast<char*>(message.payload()) << std::endl;
break;
case RdKafka::ERR__PARTITION_EOF:
{
std::cout << "到达分区的结束位置" << std::endl;
break;
}
case RdKafka::ERR__UNKNOWN_TOPIC:
case RdKafka::ERR__UNKNOWN_PARTITION:
std::cout << "消费失败,错误信息:" << message.errstr();
break;
default:
std::cout << "消费失败,错误信息:" << message.errstr();
break;
}
}
int TestRdKafka()
{
std::string brokers = "192.168.11.184:9092";
std::string errstr;
std::vector<std::string> topics{ "test"
};
std::string group_id = "test";
RdKafka::Conf *conf = RdKafka::Conf::create(RdKafka::Conf::CONF_GLOBAL);
if (conf->set("group.id", group_id, errstr)) {
std::cout << errstr << std::endl;
return -1;
}
conf->set("bootstrap.servers", brokers, errstr);
conf->set("max.partition.fetch.bytes", "1024000", errstr);
//conf->set("enable-auto-commit", "true", errstr);
RdKafka::Conf *tconf = RdKafka::Conf::create(RdKafka::Conf::CONF_TOPIC);
tconf->set("auto.offset.reset", "earliest", errstr);
conf->set("default_topic_conf", tconf, errstr);
RdKafka::KafkaConsumer *m_consumer = RdKafka::KafkaConsumer::create(conf, errstr);
if (!m_consumer) {
std::cout << "无法创建消费者,错误信息:" << errstr << std::endl;
return -1;
}
#if 0 //从上一次消费结束的位置开始消费
RdKafka::ErrorCode err = m_consumer->subscribe(topics);
if (err != RdKafka::ERR_NO_ERROR) {
std::cout << RdKafka::err2str(err) << std::endl;
return -1;
}
#else //指定每个topic的每个分区开始消费的位置
//基本思路为先获取server端的状态信息,将与订阅相关的topic找出来,根据分区,创建TopicPartion;最后使用assign消费
RdKafka::Metadata *metadataMap{ nullptr };
RdKafka::ErrorCode err = m_consumer->metadata(true, nullptr, &metadataMap, 2000);
if (err != RdKafka::ERR_NO_ERROR) {
std::cout << RdKafka::err2str(err) << std::endl;
}
const RdKafka::Metadata::TopicMetadataVector *topicList = metadataMap->topics();
std::cout << "broker topic size: " << topicList->size() << std::endl;
RdKafka::Metadata::TopicMetadataVector subTopicMetaVec;
std::copy_if(topicList->begin(), topicList->end(), std::back_inserter(subTopicMetaVec), [&topics](const RdKafka::TopicMetadata* data) {
return std::find_if(topics.begin(), topics.end(), [data](const std::string &tname) {return data->topic() == tname; }) != topics.end();
});
std::vector<RdKafka::TopicPartition*> topicpartions;
std::for_each(subTopicMetaVec.begin(), subTopicMetaVec.end(), [&topicpartions](const RdKafka::TopicMetadata* data) {
auto parVec = data->partitions();
std::for_each(parVec->begin(), parVec->end(), [&](const RdKafka::PartitionMetadata *value) {
std::cout << data->topic() << " has partion: " << value->id() << " Leader is : " << value->leader() << std::endl;
topicpartions.push_back(RdKafka::TopicPartition::create(data->topic(), value->id(), RdKafka::Topic::OFFSET_END));
});
});
m_consumer->assign(topicpartions);
#endif // 0
err = m_consumer->subscribe(topics);
if (err != RdKafka::ERR_NO_ERROR) {
std::cout << RdKafka::err2str(err) << std::endl;
return -1;
}
while (true)
{
RdKafka::Message *msg = m_consumer->consume(6000);
HandleMessage(*msg, nullptr); //消息一条消息
delete msg;
}
return 0;
}
参考
C++实现kafka的消费者客户端 - 知乎 (zhihu.com)