Make it easy to log elastic requests

[erik-kallen]

Is your feature request related to a problem? Please describe.
I want to log requests to Elastic, primarily for development/debug purposes

Describe the solution you'd like
It could either happen automatically (for example with a Logger property on ElasticSearchClientSettings), or through some callbacks.

Describe alternatives you've considered
I'm currently using this rather horrible hack:

private class LoggingHttpTransport(IElasticsearchClientSettings settings, ILogger logger) : DefaultHttpTransport<IElasticsearchClientSettings>(settings)
{
    public override TResponse Request<TResponse>(HttpMethod method, string path, PostData? data, RequestParameters? requestParameters, in OpenTelemetryData openTelemetryData)
    {
        LogRequest(method, path, data);
        return base.Request<TResponse>(method, path, data, requestParameters, in openTelemetryData);
    }

    public override Task<TResponse> RequestAsync<TResponse>(HttpMethod method, string path, PostData? data, RequestParameters? requestParameters, in OpenTelemetryData openTelemetryData, CancellationToken cancellationToken = default)
    {
        LogRequest(method, path, data);
        return base.RequestAsync<TResponse>(method, path, data, requestParameters, in openTelemetryData, cancellationToken);
    }

    private void LogRequest(HttpMethod method, string path, PostData? data)
    {
        if (data != null)
        {
            using var ms = new MemoryStream();
            data.Write(ms, Settings);
            ms.Position = 0;
            using var reader = new StreamReader(ms);
            var serializedBody = reader.ReadToEnd();
            logger.LogDebug("Calling elastic {Method} {Url}: {Body}", method, path, serializedBody);
        }
        else
        {
            logger.LogDebug("Calling elastic {Method} {Url}", method, path);
        }
    }
}

combined with this:

private static ElasticsearchClient CreateElasticSearchClient(ElasticsearchClientSettings settings, ILogger logger)
{
    var constructor = typeof(ElasticsearchClient).GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, [typeof(HttpTransport<IElasticsearchClientSettings>)]);
    return (ElasticsearchClient)constructor!.Invoke([new LoggingHttpTransport(settings, logger)]);
}

[flobernd]

Hi @erik-kallen,

there are multiple ways of logging ES queries.

1. Elastic.Clients.Elasticsearch supports OpenTelemetry
2. A debug callback can be registered:

var settings = new ElasticsearchClientSettings(new Uri("..."))
    .EnableDebugMode(cd =>
    {
        Console.WriteLine(cd.DebugInformation);
    });

Does that answer your question?

[erik-kallen]

I don't think EnableDebugMode gives me enough customizability, but I'll look into Telemetry, thank you!

[flobernd]

Happy to help! I'm closing this for now. Feel free to open another issue if you have more questions, or if the provided methods are not sufficient for your use-case.