Big data processing in C++ technology: How to use stream processing technology to process big data streams?

Stream processing technology is used for big data processing. Stream processing is a technology that processes data streams in real time. In C, Apache Kafka can be used for stream processing. Stream processing provides real-time data processing, scalability, and fault tolerance. This example uses Apache Kafka to read data from a Kafka topic and calculate the average.

Big data processing in C technology: using stream processing technology to process big data streams

Stream processing is a kind of unbounded processing Data streaming technology enables developers to process and analyze data instantly as it is generated. In C, we can use stream processing frameworks such as Apache Kafka to achieve this functionality.

Advantages of Stream Processing Framework

• Real-time data processing: Process data immediately without storage and batch processing
• Scalability: Easy Scaling to handle large data streams
• Fault tolerance: Ensure data will not be lost through fault tolerance mechanism

Practical case: Using Apache Kafka for stream processing

Let us use Apache Kafka to create a C stream processing application that will read data from a Kafka topic and calculate the average value in the data stream.

// 头文件
#include <kafka/apache_kafka.h>
#include <thread>
#include <atomic>

// 定义原子平均值计数器
std::atomic<double> avg_count(0.0);

// 流处理消费者线程
void consume_thread(const std::string& topic, rd_kafka_t* rk) {
  // 创建消费者组
  rd_kafka_consumer_group_t* consumer_group =
      rd_kafka_consumer_group_join(rk, topic.c_str(),
                                  rd_kafka_topic_partition_list_new(1), NULL);

  while (true) {
    // 订阅主题
    rd_kafka_message_t* message;
    rd_kafka_resp_err_t consumer_err =
        rd_kafka_consumer_group_poll(consumer_group, 10000, &message);
    if (consumer_err == RD_KAFKA_RESP_ERR__PARTITION_EOF) {
      rd_kafka_consumer_group_unjoin(consumer_group);
      rd_kafka_consumer_group_destroy(consumer_group);
      return;
    } else if (consumer_err != RD_KAFKA_RESP_ERR_NO_ERROR) {
      std::cerr << "Consumer error: " << rd_kafka_err2str(consumer_err) << "\n";
      continue;
    }

    // 提取并处理数据
    if (message) {
      // 提取值
      const char* message_str = static_cast<const char*>(message->payload);
      int value = std::atoi(message_str);

      // 更新原子平均值计数器
      avg_count += (static_cast<double>(value) - avg_count) /
                     (avg_count.fetch_add(1) + 1);

      if (avg_count >= 1e6) {
        std::cout << "Average: " << avg_count << "\n";
      }
    }

    // 提交偏移量
    rd_kafka_message_destroy(message);
  }
}

int main() {
  // 初始化 Kafka 实例
  rd_kafka_t* rk = rd_kafka_new(RD_KAFKA_CONSUMER, NULL, NULL, NULL);
  if (!rk) {
    std::cerr << "Failed to initialize Kafka instance\n";
    return 1;
  }

  // 配置 Kafka 实例
  char error_str[512];
  if (rd_kafka_conf_set(rk, "bootstrap.servers", "localhost:9092",
                          error_str, sizeof(error_str)) != RD_KAFKA_CONF_OK) {
    std::cerr << "Failed to set Kafka configuration: " << error_str << "\n";
    rd_kafka_destroy(rk);
    return 1;
  }

  // 创建流处理消费者线程
  std::thread consumer_thr(consume_thread, "test-topic", rk);

  // 等待消费者线程
  consumer_thr.join();

  // 销毁 Kafka 实例
  rd_kafka_destroy(rk);

  return 0;
}

Running this code will create a streaming application that reads data from the Kafka topic "test-topic" and calculates a per second average.

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