如何检查 Kafka 服务是否正在运行 #GOLang

Question

I am using the below code to push the messages to Kafka Topic. Sometimes, even when the Kafka is not running, I am getting the success response. I want to error out when the Kafka is not running. Please help.

import (
    "fmt"
    "github.com/confluentinc/confluent-kafka-go/kafka"
)

func main() {

    p, err := kafka.NewProducer(&kafka.ConfigMap{"bootstrap.servers": "localhost"})
    if err != nil {
        panic(err)
    }

    // Delivery report handler for produced messages
    go func() {
        for e := range p.Events() {
            switch ev := e.(type) {
            case *kafka.Message:
                if ev.TopicPartition.Error != nil {
                    fmt.Printf("Delivery failed: %v\n", ev.TopicPartition)
                } else {
                    fmt.Printf("Delivered message to %v\n", ev.TopicPartition)
                }
            }
        }
    }()

    // Produce messages to topic (asynchronously)
    topic := "myTopic"
    for _, word := range []string{"Welcome", "to", "the", "Confluent", "Kafka", "Golang", "client"} {
        p.Produce(&kafka.Message{
            TopicPartition: kafka.TopicPartition{Topic: &topic, Partition: kafka.PartitionAny},
            Value:          []byte(word),
        }, nil)
    }

    // Wait for message deliveries
    p.Flush(15 * 1000)
}

Answer 1

All Kafka brokers must be assigned a broker.id. On startup a broker will create an ephemeral node in Zookeeper with a path of /broker/ids/$id. As the node is ephemeral it will be removed as soon as the broker disconnects, eg by shutting down.

You can view the list of the ephemeral broker nodes like so:

echo dump | nc localhost 2181 | grep brokers.

The ZooKeeper client interface exposes a number of commands; dump lists all the sessions and ephemeral nodes for the cluster.