IElasticClient.CatHealth() works OK locally, but fails in json parsing when talking to elastic cloud instance

Elastic Stack Elasticsearch
1

Hi gang,

Context:
ElasticSearch 2.3.4
C#/.Net apps using NEST & Elasticsearch.Net 2.3.3 (next hop is of client nuget package is to 2.4.x which forces us to upgrade Newtonsoft.Json, so I'd like to avoid that if possible for now).

I have ES 2.3.4 running locally and have a suite of integration tests covering functionality leveraged by our application. All tests are passing nicely.

We're now getting ready to take the cloud-hosted step, so I set up a trial account for elastic cloud, created a cluster (also 2.3.4), set the access creds configuration (left at defaults that were generated), and then configured and aimed our tests at the new cloud-hosted cluster...

... all my indexing and search-based tests are still passing nicely.. but anything that tries to call the "Cat*"-related methods (eg. IElasticClient.CatHealth()) is failing with exceptions like this:

Result Message:
Test method IntegrationTests.ElasticSearchFtsTests.That_Cluster_Is_Accessible threw exception:
Elasticsearch.Net.UnexpectedElasticsearchClientException: Error converting value 1468428886 to type 'System.Collections.Generic.IEnumerable1[Nest.CatHealthRecord]'. Path '', line 1, position 10. ---> Newtonsoft.Json.JsonSerializationException: Error converting value 1468428886 to type 'System.Collections.Generic.IEnumerable1[Nest.CatHealthRecord]'. Path '', line 1, position 10. ---> System.ArgumentException: Could not cast or convert from System.Int64 to System.Collections.Generic.IEnumerable`1[Nest.CatHealthRecord].

... the same client code, same ES server version handles the result fine when run locally, but barfs trying to parse the results from "_cat/health" when aimed at the hosted cluster.. the results of _cat/health (via Sense) look comparable in both cases and are definitely not Json... so why it's being parsed as Json is a mystery, and understandable that the parsing is failing... but why is this handled gracefully in the local hosting scenario and not in the cloud hosted scenario?

Thanks for your help,

Tyler

2

Hi Tyler,
this seems to be a problem around headers being filtered out by Elastic Cloud. There's also an issue opened for it: https://github.com/elastic/elasticsearch-net/issues/2076 . We are discussing a fix for this, you can track progress on the issue that I posted.

Cheers
Luca

1 Like
3

Hi this is a known issue:

Elastic Cloud strips the accept header and NEST wants the cat data in json form.

You can use the lowlevel cat API instead to circumvent the problem

var client = new ElasticClient(new Uri("http://localhost:9200"));
var catHealth = client.LowLevel.CatHealth<string>();
//catHealth.Body will hold the string as returned by default by elasticsearch

or just use the .ClusterHealth() endpoint to get the same information in a more typed fashion

var clusterHealth = client.ClusterHealth();
1 Like
4

Hi Martijn, thanks for the response. Your workaround is what had fallen back to and it is working nicely. Thanks again,

Tyler