Extracting Data From Kafka REST Proxy in Go - go

Question

I am using the REST proxy instance of Kafka for producing and consuming messages.Using the API to get new messages but I am not able to convert those messages to a struct model in Go. For example:
// Get records
req, err := http.NewRequest(http.MethodGet, fmt.Sprintf(FETCH_CONSUMER, URL, GROUP, CONSUMER), nil)
if err != nil {
panic(err)
}
req.Header.Add("Accept", CONTENT_TYPE)
respRecords, err := client.Do(req)
if err != nil {
panic(err)
}
defer respRecords.Body.Close()
fmt.Printf("Response %s\n", respRecords.Status)
fmt.Println(respRecords.Body)
recordsBodyResp := bufio.NewScanner(respRecords.Body)
for recordsBodyResp.Scan() {
fmt.Printf("<--Body %s\n", recordsBodyResp.Text())
}
The value returned is in the following format:
[{"topic":"backward","key":null,"value":{"AdoptionID":"abcd123","IPAddress":"8.8.8.8","Port":"80","Status":"requested"},"partition":0,"offset":7}]
Since it's an array of objects, I want to extract the value portion of the key "value" into a struct.
That is where I am stuck.

Answer 1

You can create a struct like:
type AutoGenerated []struct {
Topic string `json:"topic"`
Key interface{} `json:"key"`
Value Value `json:"value"`
Partition int `json:"partition"`
Offset int `json:"offset"`
}
type Value struct {
AdoptionID string `json:"AdoptionID"`
IPAddress string `json:"IPAddress"`
Port string `json:"Port"`
Status string `json:"Status"`
}
And Unmarshal in that struct.
See this sample code:
package main
import (
"fmt"
"encoding/json"
)
func main() {
type Value struct {
AdoptionID string `json:"AdoptionID"`
IPAddress string `json:"IPAddress"`
Port string `json:"Port"`
Status string `json:"Status"`
}
type AutoGenerated []struct {
Topic string `json:"topic"`
Key interface{} `json:"key"`
Value Value `json:"value"`
Partition int `json:"partition"`
Offset int `json:"offset"`
}
byt := []byte(`[{"topic":"backward","key":null,"value":{"AdoptionID":"abcd123","IPAddress":"8.8.8.8","Port":"80","Status":"requested"},"partition":0,"offset":7}]`)
var dat AutoGenerated
if err := json.Unmarshal(byt, &dat); err != nil {
panic(err)
}
fmt.Printf("%#v", dat)
}