将数据以cloudevents格式发送到Kafka主题。

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英文:

Send data in cloudevents format to Kafka topic

问题

你好!根据你的描述,你想将数据以CloudEvents格式发送到Kafka。你提到的代码中,event.SetData(cloudevents.ApplicationJSON, j)这一行将数据以JSON格式设置到了CloudEvents事件中。然而,你遇到了将CloudEvents事件发送到Kafka的问题。

要解决这个问题,你需要将CloudEvents事件序列化为字符串,然后将其作为消息发送到Kafka。你可以使用json.Marshal函数将事件序列化为JSON字符串,然后将其设置为ProducerMessage的值。

以下是修改后的代码示例:

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

producerMsg := &sarama.ProducerMessage{
    Topic: tName,
    Value: sarama.StringEncoder(j),
}

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

这样,你就可以将CloudEvents事件以字符串形式发送到Kafka了。希望对你有帮助!如果还有其他问题,请随时提问。

英文:

Right now I have this code and it works fine. (It sends some json format data to Kafka topic)

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

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

but somebody wishes ho have this data in cloudevents format. -> https://github.com/cloudevents/sdk-go
so what should I do because this Event structure can not be directly casted to string.

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	// In v0.3, this field is superseded by DataContentEncoding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
}

so this code won't even compile.

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)

What should I do to send this Event to Kafka? Try to cast event.DataEncoded to string or something like that?
btw.
Programming language is golang.

答案1

得分: 2

你是否看到了文档中关于序列化事件的部分?

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

event := cloudevents.NewEvent()
event.SetSource("example/uri") 
event.SetType("example.type") 
// 这里的data是一个map[string]interface{},或者其他表示上述"example.type"模式类型的结构体类型
event.SetData(cloudevents.ApplicationJSON, data)

bytes, err := json.Marshal(event)
if err != nil {
  log.Fatal(err)
}
producerMsg := &sarama.ProducerMessage{
    Topic: s.outputTopic,
    Value: bytes,  // 你已经编码了事件
}

否则,请确保查看使用CloudEvent客户端的示例代码 https://github.com/cloudevents/sdk-go/blob/main/samples/kafka/sender/main.go

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)

... 
英文:

Did you see the section of the docs that serialized the event?

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 
}

Otherwise, be sure to look at the sample code provided that uses the CloudEvent client https://github.com/cloudevents/sdk-go/blob/main/samples/kafka/sender/main.go

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)

... 

huangapple
  • 本文由 发表于 2021年9月21日 21:04:19
  • 转载请务必保留本文链接:https://go.coder-hub.com/69269403.html
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