以cloudevents格式向Kafka topic发送数据

Question

现在我有了这段代码，它工作得很好。(向Kafka topic发送一些json格式的数据)

j, err := json.Marshal(data)
if err != nil {
    log.Fatal(err)
}
msg := &sarama.ProducerMessage{
    Topic: tName,
    Value: sarama.StringEncoder(j),
}

_, _, err = producer.SendMessage(msg)

但是有人希望ho拥有cloudevents格式的数据。我应该怎么做，因为这个事件结构不能直接转换成->。

type Event struct {
    Context     EventContext
    DataEncoded []byte
    // DataBase64 indicates if the event, when serialized, represents
    // the data field using the base64 encoding.
    // In v0.3, this field is superseded by DataContentEncoding
    DataBase64  bool
    FieldErrors map[string]error
}

所以这段代码甚至不能编译。

j, err := json.Marshal(data)
if err != nil {
    log.Fatal(err)
}

//...

event := cloudevents.NewEvent()
event.SetSource("example/uri") 
event.SetType("example.type")
event.SetData(cloudevents.ApplicationJSON, j)

producerMsg := &sarama.ProducerMessage{
    Topic: s.outputTopic,
    Value: sarama.StringEncoder(event),
}
_, _, err = s.producer.SendMessage(producerMsg)

如何将此事件发送到Kafka？尝试将event.DataEncoded转换为字符串或类似的内容？顺便说一句。编程语言是golang。

Answer 1

你看到文档中序列化事件的部分了吗？

https://github.com/cloudevents/sdk-go#serializedeserialize-a-cloudevent

event := cloudevents.NewEvent()
event.SetSource("example/uri") 
event.SetType("example.type") 
// data here is a map[string] interface{}, or some other Struct type representing the "example.type" schema type above 
event.SetData(cloudevents.ApplicationJSON, data)

bytes, err := json.Marshal(event)
if err != nil {
  log.Fatal(err)
}
producerMsg := &sarama.ProducerMessage{
    Topic: s.outputTopic,
    Value: bytes,  // you've already encoded the event 
}

否则，请务必查看所提供的使用CloudEvent客户端https://github.com/cloudevents/sdk-go/blob/main/samples/kafka/sender/main.go的示例代码

sender, err := kafka_sarama.NewSender([]string{"127.0.0.1:9092"}, saramaConfig, "test-topic")
if err != nil {
    log.Fatalf("failed to create protocol: %s", err.Error())
}

defer sender.Close(context.Background())

c, err := cloudevents.NewClient(sender, cloudevents.WithTimeNow(), cloudevents.WithUUIDs())
if err != nil {
    log.Fatalf("failed to create client, %v", err)
}

event := cloudevents.NewEvent() 
event.Set... 

c.Send(..., event)

...