Elastic.Serilog.Sinks

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A Serilog sink that writes logs directly to Elasticsearch or Elastic Cloud

Installation

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Add a reference to the Elastic.Serilog.Sinks package:

<PackageReference Include="Elastic.Serilog.Sinks" Version="8.6.0" />

Usage

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There’s a few ways that you can extend a Serilog LoggerConfiguration:

Log.Logger = new LoggerConfiguration()
	.MinimumLevel.Debug()
	.Enrich.FromLogContext()

NOTE: Don’t forget we also publish an Elastic.Apm.SerilogEnricher for the Elastic APM Agent!

Writing to Elasticsearch

.WriteTo.Elasticsearch(new [] { new Uri("http://localhost:9200" )}, opts =>
{
	opts.DataStream = new DataStreamName("logs", "console-example", "demo");
	opts.BootstrapMethod = BootstrapMethod.Failure;
	opts.ConfigureChannel = channelOpts =>
	{
		channelOpts.BufferOptions = new BufferOptions
		{
			ConcurrentConsumers = 10
		};
	};
}, transport =>
{
	// transport.Authentication(new BasicAuthentication(username, password)); // Basic Auth
	// transport.Authentication(new ApiKey(base64EncodedApiKey)); // ApiKey
})

Writing to Elastic Cloud:

.WriteTo.ElasticCloud("cloudId", "cloudUser", "cloudPass", opts =>

opts is an instance of ElasticsearchSinkOptions with the following options

Configuration

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Option Description

Transport

An instance of Elastic.Transport that dictates where and how we are communicating to. Defaults to http://localhost:9200

DataStream

Where to write data, defaults to the logs-dotnet-default datastream.

BootstrapMethod

Wheter the sink should attempt to install component and index templates to ensure the datastream has ECS mappings. Can be be either None (the default), Silent (attempt but fail silently), Failure (attempt and fail with exceptions if bootstrapping fails).

TextFormatting

Allows explicit control of over the EcsTextFormatterConfiguration used to emit ECS json documents. See Elastic.CommonSchema.Serilog for available options.

ConfigureChannel

A callback receiving the DatastreamChannelOptions which allows you to control sizing, backpressure etc. See Elastic.Ingest.Elasticsearch for more information.

Note that you can also pass ElasticsearchSinkOptions directly

.WriteTo.Elasticsearch(new ElasticsearchSinkOptions(client.Transport))

This allows you to reuse the Transport used by the Elasticsearch Client for instance.

Authentication

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When Elasticsearch security features are enabled, requests without a valid authentication header will be rejected. You can enable authentication via one of the methods below:

Basic Auth

.WriteTo.Elasticsearch(new [] { new Uri("http://localhost:9200" )}, opts =>
{
	...
}, transport =>
{
	transport.Authentication(new BasicAuthentication(username, password)); 
})

Basic authentication

API Key

.WriteTo.Elasticsearch(new [] { new Uri("http://localhost:9200" )}, opts =>
{
	...
}, transport =>
{
	transport.Authentication(new ApiKey(base64EncodedApiKey)); 
})

API Key

To learn more about authentication with the Elastic Stack, see User Authentication.

ECS Aware Message Templates

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This sink by proxy of its formatter allows you to set ECS fields directly from the message template using properties that adhere to the https://messagetemplates.org/ format.

The available ECS message template properties are listed under LogTemplateProperties.* e.g LogTemplateProperties.TraceId

Log.Information("The time is {TraceId}", "my-trace-id");

Will override trace.id on the resulting ECS json document.

Troubleshooting

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In case of issues, you can enable the [Serilog Self-Log feature](https://github.com/serilog/serilog/wiki/Debugging-and-Diagnostics#selflog) to expose any error you might have encountered.

  • Serilog.Sinks.Elasticsearch is an amazing community led sink that has a ton of options and works against older Elasticsearch versions < 8.0.
  • Serilog.Sinks.Elasticsearch is unofficially supported by Elastic with some of the .NET team helping to maintain it.
  • Elastic.Serilog.Sinks is officially supported by Elastic and was purposely build to adhere to newer best practices around logging, datastreams and ILM.
  • Elastic.Serilog.Sinks is purposely build to have fewer configuration options and be more prescriptive than Serilog.Sinks.Elasticsearch.
  • That is not to say there aren’t plenty of configuration hooks in Elastic.Serilog.Sinks

Notable absent features:

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  • Elastic.Serilog.Sinks only works with Elasticsearch 8.x and up.
  • This is because the bootrapping (BootstrapMethod) attempts to load templates build for Elasticsearch 8.0 and up.
  • Elastic.Serilog.Sinks has only one way it emits data to Elasticsearch confirming to the ecs-logging specification
  • That doesn’t mean you can not introduce your own additional properties though.
  • Elastic.Serilog.Sinks has no durable mode.
  • If you need higher guarantees on log delivery use Serilog.Sinks.File with our ECS log formatter for Serilog and use filebeat to ship these logs.
  • Check out Elastic Agent and Fleet to simplify collecting logs and metrics on the edge.

If you miss a particular feature from Serilog.Sinks.Elasticsearch in Elastic.Serilog.Sinks please open a feature request! We’d love to grow this sink organically moving forward.