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詳解C/C++如何發(fā)送與接收Kafka消息

更新時間：2024年07月17日 09:53:20 作者：周先生FullStack

系統(tǒng)之間通信方式很多如：系統(tǒng)之間調(diào)用（http/rpc等）,異步間接調(diào)用如發(fā)送消息、公共存儲等,算法工程為C/C++工程,本文將介紹如何在C/C++中如何發(fā)送與接收Kakfa消息（包含：Kafka的SASL認(rèn)證方式）,并提供了詳細(xì)的源碼和講解,需要的朋友可以參考下

一、背景

在實(shí)際工程中，難免會遇到不通系統(tǒng)之間通信，如何進(jìn)行系統(tǒng)之間通信呢？(作為一個“全棧工程師”，必須要解決它！)。

系統(tǒng)之間通信方式很多如：系統(tǒng)之間調(diào)用（http/rpc等），異步間接調(diào)用如發(fā)送消息、公共存儲等。目前，本人從事的項(xiàng)目中遇到web業(yè)務(wù)工程（Java）依賴與算法工程(C++) 處理的視頻/圖片分類與標(biāo)記結(jié)果。兩個系統(tǒng)之前數(shù)據(jù)通信采用了kafka消息方式。

算法工程為C/C++工程，本文將介紹如何在C/C++中如何發(fā)送與接收Kakfa消息（包含：Kafka的SASL認(rèn)證方式），并提供了詳細(xì)的源碼和講解。（至于Java中如何發(fā)送與接收Kakfa消息如有需要，可留言或私聊?。?/p>

二、環(huán)境依賴安裝

# 下載librdkafka
git clone https://github.com/edenhill/librdkafka.git
 
# 編譯
cd librdkafka
./configure --prefix=/usr/local
 
# 安裝
sudo make install
 
# 驗(yàn)證：查看/usr/local/lib目錄下是否有l(wèi)ibrdkafka文件
ls /usr/local/lib | grep kafka

三、編寫kakfa生產(chǎn)者消費(fèi)者

3.1 生產(chǎn)者

#include <rdkafka.h>     // 包含C API頭文件
#include <iostream>
#include <cstring>
#include <cerrno>
  
int main() {
    const char *brokers = "xx.xx.xx.xx:7091"; // Kafka broker地址
    const char *topic_name = "kafka_msg_topic_test";
    const char *payload = "Hello, Kafka from librdkafka!";
    size_t len = strlen(payload);
  
    // 創(chuàng)建配置對象
    rd_kafka_conf_t *conf = rd_kafka_conf_new();
    if (!conf) {
        std::cerr << "Failed to create configuration object: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        return 1;
    }
  
    // 設(shè)置broker地址
    if (rd_kafka_conf_set(conf, "bootstrap.servers", brokers, NULL, 0) != RD_KAFKA_CONF_OK) {
        std::cerr << "Failed to set bootstrap.servers: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_conf_destroy(conf);
        return 1;
    }
  
    // 創(chuàng)建生產(chǎn)者實(shí)例
    rd_kafka_t *rk = rd_kafka_new(RD_KAFKA_PRODUCER, conf, NULL, 0);
    if (!rk) {
        std::cerr << "Failed to create producer: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_conf_destroy(conf);
        return 1;
    }
  
    // 創(chuàng)建topic句柄（可選，但推薦）
    rd_kafka_topic_t *rkt = rd_kafka_topic_new(rk, topic_name, NULL);
    if (!rkt) {
        std::cerr << "Failed to create topic handle: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_destroy(rk);
//        rd_kafka_conf_destroy(conf);
        return 1;
    }
  
    // 發(fā)送消息
    int32_t partition = RD_KAFKA_PARTITION_UA; // 自動選擇分區(qū)
    int err = rd_kafka_produce(rkt, partition, RD_KAFKA_MSG_F_COPY, const_cast<char *>(payload), len, NULL, 0, NULL);
    if (err != RD_KAFKA_RESP_ERR_NO_ERROR) {
        std::cerr << "Failed to produce to topic " << topic_name << ": " << err << std::endl;
    } else {
        std::cout << "Produced " << len << " bytes to topic " << topic_name << std::endl;
    }
  
    // 等待所有消息發(fā)送完成（可選，但推薦）
    // 在實(shí)際生產(chǎn)代碼中，您可能需要更復(fù)雜的邏輯來處理消息的發(fā)送和確認(rèn)
    int msgs_sent = 0;
    while (rd_kafka_outq_len(rk) > 0) {
        rd_kafka_poll(rk, 100); // 輪詢Kafka隊(duì)列，直到所有消息都發(fā)送出去
        msgs_sent += rd_kafka_outq_len(rk);
    }
  
    // 銷毀topic句柄
    rd_kafka_topic_destroy(rkt);
  
    // 銷毀生產(chǎn)者實(shí)例
    rd_kafka_destroy(rk);
  
    // 銷毀配置對象
//    rd_kafka_conf_destroy(conf);
  
    return 0;
}

3.2 消費(fèi)者

#include <rdkafka.h>
#include <iostream>
#include <cerrno>
#include <cstring>
#include <cstdlib>
  
void error_cb(rd_kafka_t *rk, int err, const char *reason, void *opaque) {
    // 錯誤處理回調(diào)
    std::cerr << "Kafka error: " << err << ": " << reason << std::endl;
}
  
int main() {
    std::cerr << "start " << std::endl;
    const char *brokers = "xx.xx.xx.xx:7091"; // Kafka broker地址
    const char *group_id = "kafka_msg_topic_test"; // 消費(fèi)者組ID
    const char *topic_name = "kafka_msg_topic_test"; // Kafka topic名稱
    
    // 創(chuàng)建配置對象
    rd_kafka_conf_t *conf = rd_kafka_conf_new();
    if (!conf) {
        std::cerr << "Failed to create configuration object: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        return 1;
    }
    
    // 設(shè)置broker地址
    if (rd_kafka_conf_set(conf, "bootstrap.servers", brokers, NULL, 0) != RD_KAFKA_CONF_OK) {
        std::cerr << "Failed to set bootstrap.servers: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_conf_destroy(conf);
        return 1;
    }
    
    // 設(shè)置消費(fèi)者組ID
    if (rd_kafka_conf_set(conf, "group.id", group_id, NULL, 0) != RD_KAFKA_CONF_OK) {
        std::cerr << "Failed to set group.id: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_conf_destroy(conf);
        return 1;
    }
    
    // 設(shè)置錯誤處理回調(diào)（可選）
    rd_kafka_conf_set_error_cb(conf, error_cb);
    
    // 創(chuàng)建消費(fèi)者實(shí)例
    rd_kafka_t *rk = rd_kafka_new(RD_KAFKA_CONSUMER, conf, NULL, 0);
    if (!rk) {
        std::cerr << "Failed to create consumer: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        return 1;
    }
    
    
    // 創(chuàng)建一個topic分區(qū)列表
    rd_kafka_topic_partition_list_t *topics = rd_kafka_topic_partition_list_new(1);
    if (!topics) {
        std::cerr << "Failed to create topic partition list: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_destroy(rk);
        return 1;
    }
    
    // 添加topic到分區(qū)列表
    if (!rd_kafka_topic_partition_list_add(topics, topic_name, RD_KAFKA_PARTITION_UA)) {
        std::cerr << "Failed to add topic to partition list: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_topic_partition_list_destroy(topics);
        rd_kafka_destroy(rk);
        return 1;
    }
    // 訂閱topic
    rd_kafka_resp_err_t err = rd_kafka_subscribe(rk, topics);
    if (err != RD_KAFKA_RESP_ERR_NO_ERROR) {
        std::cerr << "Failed to subscribe to topic: " << rd_kafka_err2str(err) << std::endl;
        rd_kafka_topic_partition_list_destroy(topics);
        rd_kafka_destroy(rk);
        return 1;
    }
    
    // 銷毀分區(qū)列表（訂閱后不再需要）
    rd_kafka_topic_partition_list_destroy(topics);
    
    
    // 輪詢消息
    while (true) {
        rd_kafka_message_t *rkmessage;
        rkmessage = rd_kafka_consumer_poll(rk, 1000); // 等待1秒以獲取消息
        
        if (rkmessage == NULL) {
            // 沒有消息或者超時
            continue;
        }
        
        if (rkmessage->err) {
            // 處理錯誤
            if (rkmessage->err == RD_KAFKA_RESP_ERR__PARTITION_EOF) {
                // 消息流的末尾
                std::cout << "End of partition event" << std::endl;
            } else {
                // 打印錯誤并退出
                std::cerr << "Kafka consumer error: " << rd_kafka_message_errstr(rkmessage) << std::endl;
                break;
            }
        } else {
            // 處理消息
            std::cout << "Received message at offset " << rkmessage->offset
            << " from partition " << rkmessage->partition
            << " with key \"" << rkmessage->key << "\" and payload size "<< rkmessage->len
            << " value :" <<(char *)rkmessage->payload
            << std::endl;
            
            // 如果需要，可以在這里處理消息內(nèi)容
            // 例如，使用rkmessage->payload()獲取消息內(nèi)容
            
            // 釋放消息
            rd_kafka_message_destroy(rkmessage);
        }
    }
    
    // 清理
    rd_kafka_destroy(rk);
    
    return 0;
}

3.3 編譯運(yùn)行

3.3.1 編譯生產(chǎn)者消費(fèi)者

g++ -o send_kafka SendKakfaMessage.cpp -I/usr/local/include/librdkafka -lrdkafka++ -lrdkafka -lpthread

g++ -o receive_kafka ReceiveKafkaMessage.cpp -I/usr/local/include/librdkafka -lrdkafka++ -lrdkafka -lpthread

3.3.2 運(yùn)行驗(yàn)證

執(zhí)行時，若出現(xiàn)錯誤： error while loading shared libraries: librdkafka++.so.1: cannot open shared object file: No such file or directory

則需要執(zhí)行下面環(huán)境變量配置：

export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH

生產(chǎn)者：發(fā)送消息

消費(fèi)者：接收消息

3.4 SASL認(rèn)證kakfa

下面是，支持sasl認(rèn)證的kakka生產(chǎn)者完整代碼

#include <rdkafka.h>
#include <iostream>
#include <cstring>
#include <cerrno>
 
int main(int argc, char *argv[]) {
    const char *brokers = "xx.xx.xx.xx:8092"; // Kafka broker地址
    const char *username = "xxx";
    const char *password = "xxx";
    const char *topic_name = "kafka_msg_test_sasl";
    const char *payload = "Hello, Kafka from librdkafka! sasl";
    size_t len = strlen(payload);
     // 初始化配置
    rd_kafka_conf_t *conf = rd_kafka_conf_new();
    if (!conf)
    {
        std::cerr << "Failed to create configuration object: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        return 1;
    }
    char errstr[512]; // 聲明一個足夠大的字符數(shù)組來存儲錯誤信息
 
    // 設(shè)置SASL相關(guān)的配置
    if (rd_kafka_conf_set(conf, "security.protocol", "SASL_PLAINTEXT", errstr, sizeof(errstr)) != RD_KAFKA_CONF_OK)
    {
        std::cerr << "Failed to set security.protocol: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_conf_destroy(conf);
        return 1;
    }
    if (rd_kafka_conf_set(conf, "sasl.mechanisms", "PLAIN", errstr, sizeof(errstr)) != RD_KAFKA_CONF_OK)
    {
        std::cerr << "Failed to set sasl.mechanisms: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_conf_destroy(conf);
        return 1;
    }
    if (rd_kafka_conf_set(conf, "sasl.username", username, errstr, sizeof(errstr)) != RD_KAFKA_CONF_OK)
    {
        std::cerr << "Failed to set sasl.username: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_conf_destroy(conf);
        return 1;
    }
    if (rd_kafka_conf_set(conf, "sasl.password", password, errstr, sizeof(errstr)) != RD_KAFKA_CONF_OK)
    {
        std::cerr << "Failed to set sasl.password: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_conf_destroy(conf);
        return 1;
    }
 
    if (rd_kafka_conf_set(conf, "bootstrap.servers", brokers, errstr, sizeof(errstr)) != RD_KAFKA_CONF_OK)
    {
        std::cerr << "Failed to set bootstrap.servers: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_conf_destroy(conf);
        return 1;
    }
    // 檢查配置是否設(shè)置成功
    if (rd_kafka_conf_set(conf, "security.protocol", "SASL_PLAINTEXT", errstr, sizeof(errstr)) != RD_KAFKA_CONF_OK) {
        std::cerr << "Failed to set configuration: " << errstr << std::endl;
        return 1;
    }
 
    // 創(chuàng)建producer實(shí)例
    rd_kafka_t *rk = rd_kafka_new(RD_KAFKA_PRODUCER, conf, errstr, sizeof(errstr));
    if (!rk) {
        std::cerr << "Failed to create new producer: " << errstr << std::endl;
        return 1;
    }
 
    // 創(chuàng)建topic句柄（可選，但推薦）
    rd_kafka_topic_t *rkt = rd_kafka_topic_new(rk, topic_name, NULL);
    if (!rkt)
    {
        std::cerr << "Failed to create topic handle: " << rd_kafka_err2str(rd_kafka_last_error()) << std::endl;
        rd_kafka_destroy(rk);
        //        rd_kafka_conf_destroy(conf);
        return 1;
    }
 
    // 發(fā)送消息
    int32_t partition = RD_KAFKA_PARTITION_UA; // 自動選擇分區(qū)
    int err = rd_kafka_produce(rkt, partition, RD_KAFKA_MSG_F_COPY, const_cast<char *>(payload), len, NULL, 0, NULL);
    if (err != RD_KAFKA_RESP_ERR_NO_ERROR)
    {
        std::cerr << "Failed to produce to topic " << topic_name << ": " << err << std::endl;
    }
    else
    {
        std::cout << "Produced " << len << " bytes to topic " << topic_name << std::endl;
    }
 
    // 等待所有消息發(fā)送完成（可選，但推薦）
    // 在實(shí)際生產(chǎn)代碼中，您可能需要更復(fù)雜的邏輯來處理消息的發(fā)送和確認(rèn)
    int msgs_sent = 0;
    while (rd_kafka_outq_len(rk) > 0)
    {
        rd_kafka_poll(rk, 100); // 輪詢Kafka隊(duì)列，直到所有消息都發(fā)送出去
        msgs_sent += rd_kafka_outq_len(rk);
    }
 
    // 銷毀topic句柄
    rd_kafka_topic_destroy(rkt);
 
    // 清理資源
    rd_kafka_destroy(rk);
    return 0;
}

在kafka map 管理界面中查看發(fā)送效果如下：