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基于 Docker 容器运行的 Kafka + C++ 练手项目

使用 C++ 语言调用 Kafka 接口的示例项目，通过容器化部署 Kafka + Zookeeper 环境，实现了 Kafka 生产者与消费者的基本功能。

1 项目目的

• 学习如何用 C++ 操作 Kafka（使用 librdkafka 的 C++ 封装）
• 实践分布式消息队列的基本使用模式：生产者-消费者
• 通过 Docker 快速部署 Kafka + Zookeeper 环境
• 为将来构建中间件（如日志系统、异步任务系统、RPC 框架）奠定基础

2 项目框架

cpp-kafka-project/
├── docker-compose.yml # Kafka + Zookeeper + 开发环境容器定义
├── cpp_kafka_code/
│   ├── CMakeLists.txt
│   ├── producer.cpp
│   ├── consumer.cpp
│   └── create_topic.sh # 创建 topic 的脚本

关键技术点

1. Kafka + Zookeeper 容器化

   • 使用 Confluent 提供的官方镜像：confluentinc/cp-kafka 和 cp-zookeeper

   • 通过 docker-compose.yml 启动三个容器：

     • zookeeper：协调 Kafka Broker
     • kafka：消息代理
     • cpp_dev：Ubuntu 开发容器，内含 C++ 源码和构建环境

2. Kafka C++ 客户端库

   • 使用 librdkafka 的 C++ 封装接口 rdkafkacpp.h
   • 动态链接 librdkafka++ 和 librdkafka

3. CMake 构建系统

   • 自动查找和链接 Kafka 所需的库与头文件
   • 支持分离构建（out-of-source）

3 代码

docker-compose.yml

version: "3.8"services:zookeeper:image: confluentinc/cp-zookeeper:7.5.0container_name: zookeeperports:- "2181:2181"environment:ZOOKEEPER_CLIENT_PORT: 2181ZOOKEEPER_TICK_TIME: 2000kafka:image: confluentinc/cp-kafka:7.5.0container_name: kafkaports:- "9092:9092"environment:KAFKA_BROKER_ID: 1KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://kafka:9092KAFKA_LISTENERS: PLAINTEXT://0.0.0.0:9092KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1depends_on:- zookeeperdev:image: ubuntu:22.04container_name: cpp_devtty: truestdin_open: truecommand: /bin/bashworking_dir: /home/dev/codevolumes:- ./cpp_kafka_code:/home/dev/codedepends_on:- kafka

create-topic.sh

#!/bin/bashdocker exec kafka kafka-topics \--create \--topic test_topic \--bootstrap-server localhost:9092 \--partitions 1 \--replication-factor 1

加执行权限

chmod +x create_topic.sh

CMakeLists.txt

cmake_minimum_required(VERSION 3.10)
project(cpp_kafka_example)set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)find_package(PkgConfig REQUIRED)
pkg_check_modules(RDKAFKA REQUIRED IMPORTED_TARGET rdkafka++)add_executable(producer producer.cpp)
target_link_libraries(producer PkgConfig::RDKAFKA)add_executable(consumer consumer.cpp)
target_link_libraries(consumer PkgConfig::RDKAFKA)

producer.cpp

#include <librdkafka/rdkafkacpp.h>
#include <iostream>
#include <csignal>
#include <memory>class ExampleEventCb : public RdKafka::EventCb {void event_cb(RdKafka::Event &event) override {if (event.type() == RdKafka::Event::EVENT_ERROR) {std::cerr << "Kafka Error: " << event.str() << std::endl;}}
};int main() {std::string brokers = "kafka:9092";std::string topic_str = "test_topic";std::string errstr;// 配置ExampleEventCb event_cb;std::unique_ptr<RdKafka::Conf> conf(RdKafka::Conf::create(RdKafka::Conf::CONF_GLOBAL));conf->set("bootstrap.servers", brokers, errstr);conf->set("event_cb", &event_cb, errstr);// 创建 producerstd::unique_ptr<RdKafka::Producer> producer(RdKafka::Producer::create(conf.get(), errstr));if (!producer) {std::cerr << "Failed to create producer: " << errstr << std::endl;return 1;}// 创建 Topicstd::unique_ptr<RdKafka::Topic> topic(RdKafka::Topic::create(producer.get(), topic_str, nullptr, errstr));if (!topic) {std::cerr << "Failed to create topic: " << errstr << std::endl;return 1;}std::string message = "Hello from C++ Kafka Producer!";RdKafka::ErrorCode resp = producer->produce(topic.get(),                            // topic ptrRdKafka::Topic::PARTITION_UA,           // partitionRdKafka::Producer::RK_MSG_COPY,         // message flagsconst_cast<char *>(message.c_str()),    // payloadmessage.size(),                         // payload sizenullptr,                                // optional keynullptr);                               // opaqueif (resp != RdKafka::ERR_NO_ERROR) {std::cerr << "Produce failed: " << RdKafka::err2str(resp) << std::endl;} else {std::cout << "Message sent successfully\n";}producer->flush(3000);return 0;
}

consumer.cpp

#include <librdkafka/rdkafkacpp.h>
#include <iostream>
#include <csignal>
#include <memory>bool running = true;void signal_handler(int) {running = false;
}class ExampleEventCb : public RdKafka::EventCb {void event_cb(RdKafka::Event &event) override {if (event.type() == RdKafka::Event::EVENT_ERROR) {std::cerr << "Kafka Error: " << event.str() << std::endl;}}
};int main() {signal(SIGINT, signal_handler);std::string brokers = "kafka:9092";std::string topic = "test_topic";std::string group_id = "cpp_consumer_group";std::string errstr;ExampleEventCb event_cb;auto conf = RdKafka::Conf::create(RdKafka::Conf::CONF_GLOBAL);conf->set("bootstrap.servers", brokers, errstr);conf->set("group.id", group_id, errstr);conf->set("auto.offset.reset", "earliest", errstr);conf->set("event_cb", &event_cb, errstr);auto consumer = RdKafka::KafkaConsumer::create(conf, errstr);if (!consumer) {std::cerr << "Failed to create consumer: " << errstr << std::endl;return 1;}consumer->subscribe({topic});std::cout << "Consuming messages from topic " << topic << std::endl;while (running) {auto msg = consumer->consume(1000);if (msg->err() == RdKafka::ERR_NO_ERROR) {std::string message(reinterpret_cast<const char*>(msg->payload()), msg->len());std::cout << "Received message: " << message << std::endl;}}delete msg;}consumer->close();delete consumer;return 0;
}

4 编译运行

1. 启动容器

# docker-compose.yml所在目录下
docker-compose up -d

2. 安装依赖并编译

docker exec -it cpp_dev /bin/bash
# 以下在容器内执行
apt update && apt install -y g++ cmake pkg-config librdkafka-dev librdkafka++1
mkdir -p build && cd build
cmake ..
make

3. 创建kafka topic：

# 宿主机下
./create_topic.sh

4. cpp_dev容器下运行consumer和producer

./consumer &
./producer

输出

/home/dev/code/build# ./consumer &
[1] 4069
/home/dev/code/build# Consuming messages from topic test_topic/home/dev/code/build# ./producer 
Message sent successfully
Received message: Hello from C++ Kafka Producer!

5 功能与接口说明

5.1 Producer 接口：producer.cpp

功能：向指定的 topic（如 test_topic）持续发送消息。

关键调用流程

RdKafka::Conf::create(...)                     // 创建配置对象
conf->set(...)                                 // 设置 broker 等参数
RdKafka::Producer::create(...)                 // 创建 Producer 实例
producer->produce(...)                         // 发送消息

参数说明

参数	说明
topic	目标 topic 名称
partition	使用 RdKafka::Topic::PARTITION_UA 表示由 Kafka 自动分配
message flags	通常为 RK_MSG_COPY
payload	消息数据（char*）
payload length	消息长度（size_t）

---

5.2 Consumer 接口：consumer.cpp

功能：从指定的 topic 订阅并消费消息。

关键调用流程

RdKafka::Conf::create(...)                     // 创建全局配置
conf->set(...)                                 // 设置 group.id 等参数
RdKafka::KafkaConsumer::create(...)            // 创建 KafkaConsumer 实例
consumer->subscribe(...)                       // 订阅 topic
consumer->consume(...)                         // 拉取消息

消费流程中注意

• msg->payload() 需要转换为 char* 后构造成字符串打印
• 使用 msg->err() 判断是否正常收到消息

5.3 工程技术点

技术点	描述
容器部署	无需本机安装 Kafka，快速启动测试环境
Kafka 消费模型	使用 KafkaConsumer 拉模式消费，便于理解
CMake 模块化	可轻松扩展更多模块（如 logger、metrics）
中间件模板	可作为日志系统、消息队列、调度中心等中间件的原型