[FEATURE] Allow basic auth for non-cloud node types

[irontoby]

ECS integration/library project(s) (e.g. Elastic.CommonSchema.Serilog): Elasticsearch.Extensions.Logging

Is your feature request related to a problem? Please describe.
Our self-hosted Elasticsearch instance requires HTTP basic auth. (Note, we are using the docker-compose setup from this project). However, the Username and Password config settings are only used for Cloud node types.

Describe the solution you'd like
Allow using Username/Password for single node pools also.

Describe alternatives you've considered
I was able to work around this by using e.g. https://username:password@example.com as the URL but it would be better if I could store the username/password separately and provide them via secure means (Azure KeyVault in our case).

Additional context
It looks like fixing this would also involve updating SingleNodePool from elastic-transport-net to have the same AuthenticationHeader as CloudNodePool so I wasn't sure if I should file an issue in both places. I didn't see any existing related issues in that repo either.

[Mpdreamz]

Through code you can always create your own transport (or reuse one from an ElasticsearchClient):

loggingBuilder.AddElasticsearch(CreateTransport(), loggerOpts =>
{
	//
}, channelOpts =>
{
	//
});

static HttpTransport CreateTransport()
{
	var pool = new SingleNodePool(new Uri("http://localhost:9200"));
	var config = new TransportConfiguration(pool)
		.Authentication(new BasicAuthentication("u", "p"));
	return new DefaultHttpTransport(config);

}

Through config however

  "Logging": {
    "Elasticsearch": {
      "Tags": [ "Development", "Example" ],
      "IndexOffset": "00:00",
      "IsEnabled": true,
      "IncludeScopes": true,
      "IncludeHost": true,
      "IncludeProcess": true,
      "IncludeUser": true,
      "ShipTo": {
        "NodePoolType": "SingleNode",
        "NodeUris": [ "http://localhost:9200" ],
		"Username": "u",
		"Password": "p"
      }
    },
    "LogLevel" : {
      "Default": "Trace",
      "Microsoft": "Warning"
    }
  }
}

Username/Password and ApiKey currently only will be applied when NodePoolType ==
Cloud.

I will create a PR to rectify this, thank you for bringing this to our attention @irontoby!

[irontoby]

@Mpdreamz thanks for the update, I saw the option to add my own HttpTransport but once I started looking through the code I wasn't comfortable enough in creating my own instance and being sure I didn't miss anything. But I'll give your code a try!

[Mpdreamz]

#313 should fix configuring authentication through config.