Go.Imp.Insert.Partial

package main

import (
  "bytes"
  "fmt"
  "io"
  "io/ioutil"
  "log"
  "mime/multipart"
  "net/http"
  "net/url"
  "os"
)

func main() {
  u, err := url.Parse("http://localhost:9000")
  checkErr(err)
  u.Path += "imp"
  url := fmt.Sprintf("%v", u)
  fileName := "/path/to/data.csv"
  file, err := os.Open(fileName)
  checkErr(err)

  defer file.Close()

  buf := new(bytes.Buffer)
  writer := multipart.NewWriter(buf)
  uploadFile, _ := writer.CreateFormFile("data", "data.csv")
  _, err = io.Copy(uploadFile, file)
  checkErr(err)
  writer.Close()

  req, err := http.NewRequest(http.MethodPut, url, buf)
  checkErr(err)
  req.Header.Add("Content-Type", writer.FormDataContentType())

  client := &http.Client{}
  res, err := client.Do(req)
  checkErr(err)

  defer res.Body.Close()

  body, err := ioutil.ReadAll(res.Body)
  checkErr(err)

  log.Println(string(body))
}

func checkErr(err error) {
  if err != nil {
    panic(err)
  }
}