Go elasticsearch bulk insert - go

Question

I have been unable to solve the problem into elasticsearch Bulk method for several days, since I am not strong in Go and started learning it not so long ago, while executing the code :
package main
import (
"bytes"
json "encoding/json"
"fmt"
"io/ioutil"
"log"
"net/http"
)
type BulkInsertMetaData struct {
Index []BulkInsertIndex `json:"index"`
}
type BulkInsertIndex struct {
Index string `json:"_index"`
ID string `json:"_id"`
}
type BulInsertData struct {
Url string `json:"url"`
}
func main() {
dataMeta := BulkInsertMetaData{
Index: []BulkInsertIndex{
{
Index: "Test",
ID: "1234567890",
},
},
}
data := BulInsertData{
Url: "http://XXXX.XX",
}
TojsBulInsertData, _ := json.Marshal(data)
TojsBulkInsertMetaData, _ := json.Marshal(dataMeta)
BulkMetaData := bytes.NewBuffer(append(TojsBulkInsertMetaData, []byte("\n")...))
BulkData := bytes.NewBuffer(append(TojsBulInsertData, []byte("\n")...))
log.Println(BulkMetaData)
log.Println(BulkData)
respMetaData, err := http.Post("http://127.0.0.1:9200/_bulk", "application/json", BulkMetaData)
if err != nil {
log.Println(err)
}
body, err := ioutil.ReadAll(respMetaData.Body)
if err != nil {
log.Println(err)
}
fmt.Println(string(body))
respBulkData, err := http.Post("http://127.0.0.1:9200/_bulk", "application/json", BulkData)
if err != nil {
log.Println(err)
}
body2, err := ioutil.ReadAll(respBulkData.Body)
if err != nil {
log.Println(err)
}
fmt.Println(string(body2))
}
but i get an error:
2022/02/09 14:37:02 {"index":[{"_index":"Test","_id":"1234567890"}]}
2022/02/09 14:37:02 {"url":"http://XXXX.XX"}
{"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"Malformed action/metadata line [1], expected START_OBJECT or END_OBJECT but found [START_ARRAY]"}],"type":"illegal_argument_exception","reason":"Malformed action/metadata line [1], expected START_OBJECT or END_OBJECT but found [START_ARRAY]"},"status":400}
please help and explain what I'm doing wrong, I searched the Internet for the answer to my question but did not find
I test insert when using REST client passes without problems

Answer 1

BulkMetaData should be {"index":{"_index":"Test","_id":"1234567890"}} (without []) and it should be sent to /_bulk together with BulkData, as a single payload:
{"index":{"_index":"Test","_id":"1234567890"}}
{"url":"http://XXXX.XX"}

Answer 2

Sorry for kinda necroing but I also recently needed to design a Bulk connector in our codebase and the fact that there are NO NDJSON encoder/decoders out on the web is appalling. Here is my implementation:
func ParseToNDJson(data []map[string]interface{}, dst *bytes.Buffer) error {
enc := json.NewEncoder(dst)
for _, element := range data {
if err := enc.Encode(element); err != nil {
if err != io.EOF {
return fmt.Errorf("failed to parse NDJSON: %v", err)
}
break
}
}
return nil
}
Driver code to test:
func main() {
var b bytes.Buffer
var data []map[string]interface{}
// pointless data generation...
for i, name := range []string{"greg", "sergey", "alex"} {
data = append(data, map[string]interface{}{name: i})
}
if err := ParseToNDJson(query, &body); err != nil {
return nil, fmt.Errorf("error encoding request: %s", err)
}
res, err := esapi.BulkRequest{
Index: "tasks",
Body: strings.NewReader(body.String()),
}.Do(ctx, q.es)
Hope this helps someone