Elasticsearch in Go, Err: "the client noticed that the server is not Elasticsearch and we do not support this unknown product"

Question

I'm working on using Elasticsearch in Go, I followed this guide: https://developer.okta.com/blog/2021/04/23/elasticsearch-go-developers-guide

I set up Elastic with docker. Verify that Elasticsearch is running:

$ curl http://localhost:9200
{
  "name" : "0e9e2916eca5",
  "cluster_name" : "docker-cluster",
  "cluster_uuid" : "jh8PVKNASpO3uK87Jzoq6Q",
  "version" : {
    "number" : "7.5.2",
    "build_flavor" : "default",
    "build_type" : "docker",
    "build_hash" : "8bec50e1e0ad29dad5653712cf3bb580cd1afcdf",
    "build_date" : "2020-01-15T12:11:52.313576Z",
    "build_snapshot" : false,
    "lucene_version" : "8.3.0",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },
  "tagline" : "You Know, for Search"
}

Also from the browser seems fine.

Next I set up a sample Go program just to test it out:

package main

import (
    "testing"
    "github.com/elastic/go-elasticsearch/v8"
)

func Test_elastic(t *testing.T) {

    es, err := elasticsearch.NewDefaultClient()
    if err != nil {
     panic(err)
    }

    res, err := es.Info()
    if err != nil {
     panic(err)
    }
    defer res.Body.Close()
}

but res returns with err:

"the client noticed that the server is not Elasticsearch and we do not support this unknown product"

Digging in the code I see it verifies the response by looking for header.Get("X-Elastic-Product") == "Elasticsearch".

I have no idea why it's not working and I couldn't find any reference for this error online... would appreciate any input on this.

Answer 1

You are using v8 of the elasticsearch client, but v7.5.2 of elasticsearch itself. You need to use the library version corresponding to the elasticsearch version, like github.com/elastic/go-elasticsearch/v7. It seems that the check for the header was only added recently in order to not make the library work with any forks.