Bulk Load

[LesioS]

Sorry in advance, if it's wrong place, but I haven't found better.

I've app written in Go where I try to make bulk load to ES. My code looks similar to:

	url := c.url + "/" + sess.SessionIndexName + "/sess/_bulk"

	idrow := IdRow{
		Index: Index{
			Index: sess.SessionIndexName,
			ID:    sess.SessionID,
		},
	}

	sessionDoc, err := ffjson.Marshal(sess.SessionDoc)
	if err != nil {
		// error queue
		return
	}
	idx, err := ffjson.Marshal(idrow)
	if err != nil {
		//  error queue
		return
	}

	body += fmt.Sprintf("%s\n", idx)
	body += fmt.Sprintf("%s\n", sessionDoc)

	req, err := http.NewRequest("POST",	url, bytes.NewBufferString(body))
	auth := base64.StdEncoding.EncodeToString([]byte(c.login + ":" + c.password))
	req.Header.Add("Authorization","Basic " + auth)

	req.Header.Set("Content-Type", "application/x-ndjson")

	resp, err := c.client.Do(req)
	if err != nil {
		//  error queue
		return
	}
	defer resp.Body.Close()

sess.SessionIndexName contains session which comes from mapping:
PUT session { "mappings": { "sess": { "properties": {...

Final call is here:
resp, err := c.client.Do(req) if err != nil {...

err return null, which means that everything is OK. resp in header has code '200 OK' which also states success.
But there's no success: doc is not visible under Dev Tool in Kibana. Call GET session/_search always returns:
{ "took": 1, "timed_out": false, "_shards": { "total": 5, "successful": 5, "skipped": 0, "failed": 0 }, "hits": { "total": 0, "max_score": null, "hits": [] } }

Calling curl --user xxx:yyy --insecure -H "Content-Type: application/x-ndjson" -XPOST https://localhost:9200/session/sess/_bulk?pretty --data-binary @test.json with doc in test.json file loads data properly to ES.

Any tips what's wrong?