Real-time stream processing using Kafka and Flink in Beego-Golang-php.cn

Real-time stream processing using Kafka and Flink in Beego

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Release： 2023-06-22 16:18:33

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With the advent of the big data era, we often need to process and analyze real-time data. Real-time stream processing technology has become a mainstream method for processing large-scale real-time data due to its high performance, high scalability and low latency. In real-time stream processing technology, Kafka and Flink are common components and have been widely used in many enterprise-level data processing systems. In this article, we will introduce how to use Kafka and Flink in Beego for real-time stream processing.

1. Introduction to Kafka

Apache Kafka is a distributed stream processing platform. It provides high performance, high availability, high scalability and some advanced features, such as Exactly-Once guarantee, by decoupling data into a stream (streaming data) and distributing the data across multiple nodes. The main role of Kafka is as a reliable messaging system that can be used to solve communication problems between multiple components in distributed systems and reliable transmission of messages.

2. Introduction to Flink

Flink is an event-driven, distributed, high-performance big data stream processing framework. It supports stream and batch processing, has SQL-like query and stream processing capabilities, supports highly composable streaming computing, and has rich window and data storage support.

3. Kafka in Beego

Using Kafka in Beego is mainly divided into two parts, namely Kafka consumer and Kafka producer.

Kafka producer

Using Kafka producers in Beego can easily send data to the Kafka cluster. Here is how to use Kafka producers in Beego Example:

import (
    "github.com/Shopify/sarama"
)

func main() {
    // 创建 kafka 生产者
    producer, err := sarama.NewSyncProducer([]string{"localhost:9092"}, nil)

    if err != nil {
        // 处理错误情况
        panic(err)
    }

    // 创建 Kafka 消息
    msg := &sarama.ProducerMessage{
        Topic: "test",
        Value: sarama.StringEncoder("Hello, World!"),
    }

    // 发送消息
    partition, offset, err := producer.SendMessage(msg)

    if err != nil {
        // 处理错误情况
        panic(err)
    }

    fmt.Printf("消息已发送到分区 %d 的偏移量 %d 中
", partition, offset)

    // 关闭 Kafka 生产者
    producer.Close()
}

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Kafka Consumer

Using Kafka consumers in Beego can easily obtain data from the Kafka cluster. Here is how to use it in Beego Example of Kafka consumer:

import (
    "github.com/Shopify/sarama"
)

func main() {
    // 创建 kafka 消费者
    consumer, err := sarama.NewConsumer([]string{"localhost:9092"}, nil)

    if err != nil {
        // 处理错误情况
        panic(err)
    }

    // 订阅 Topic
    partitions, err := consumer.Partitions("test")

    if err != nil {
        // 处理错误情况
        panic(err)
    }

    for _, partition := range partitions {
        // 从分区的开头读取数据
        partitionConsumer, _ := consumer.ConsumePartition("test", partition, sarama.OffsetOldest)

        // 处理数据
        go func(partitionConsumer sarama.PartitionConsumer) {
            for {
                select {
                case msg := <-partitionConsumer.Messages():
                    // 处理消息
                    fmt.Printf("收到消息: %v", string(msg.Value))
                }
            }
        }(partitionConsumer)
    }

    // 关闭 Kafka 消费者
    defer consumer.Close()
}

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4. Flink in Beego

Using Flink in Beego can be done directly through Flink’s Java API, through the Cgo interaction between Java and Go Complete the entire process. Below is a simple example from Flink where the frequency of each Socket text word is calculated via real-time stream processing. In this example, we read the given text data stream into Flink, then use Flink's operators to operate on the data stream, and finally output the results to the console.

Create a Socket text data source

import org.apache.flink.streaming.api.functions.source.SourceFunction;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.Socket;

public class SocketTextStreamFunction implements SourceFunction<String> {
    private final String hostname;
    private final int port;

    public SocketTextStreamFunction(String hostname, int port) {
        this.hostname = hostname;
        this.port = port;
    }

    public void run(SourceContext<String> context) throws Exception {
        Socket socket = new Socket(hostname, port);
        BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        String line;
        while ((line = reader.readLine()) != null) {
            context.collect(line);
        }
        reader.close();
        socket.close();
    }

    public void cancel() {}
}

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Calculate the frequency of each word

import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.windowing.WindowFunction;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.streaming.api.windowing.windows.TimeWindow;
import org.apache.flink.util.Collector;

public class SocketTextStreamWordCount {
    public static void main(String[] args) throws Exception {
        String hostname = "localhost";
        int port = 9999;

        final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        // 从 Socket 中读取数据流
        DataStream<String> text = env.addSource(new SocketTextStreamFunction(hostname, port));

        // 计算每个单词的出现频率
        DataStream<Tuple2<String, Integer>> wordCounts = text
                .flatMap(new FlatMapFunction<String, Tuple2<String, Integer>>() {
                    public void flatMap(String value, Collector<Tuple2<String, Integer>> out) throws Exception {
                        String[] words = value.toLowerCase().split("\W+");
                        for (String word : words) {
                            out.collect(new Tuple2<String, Integer>(word, 1));
                        }
                    }
                })
                .keyBy(0)
                .timeWindow(Time.seconds(5))
                .apply(new WindowFunction<Tuple2<String, Integer>, Tuple2<String, Integer>, Tuple, TimeWindow>() {
                    public void apply(Tuple key, TimeWindow window, Iterable<Tuple2<String, Integer>> input, Collector<Tuple2<String, Integer>> out) throws Exception {
                        int sum = 0;
                        for (Tuple2<String, Integer> t : input) {
                            sum += t.f1;
                        }
                        out.collect(new Tuple2<String, Integer>((String) key.getField(0), sum));
                    }
                });

        // 打印到控制台
        wordCounts.print();

        env.execute("Socket Text Stream Word Count");
    }
}

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5. Conclusion

This article introduces how to use Kafka and Flink in Beego for real-time stream processing. Kafka can be used as a reliable messaging system to solve communication problems between multiple components in distributed systems and reliable transmission of messages. Flink is an event-driven, distributed, high-performance big data stream processing framework. In practical applications, we can flexibly choose to use technologies such as Kafka and Flink based on specific needs to solve challenges in large-scale real-time data processing.

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