ReadMe.md

Dotnet Distributed Tracing Examples

Example of distributed tracing in .NET, using W3C Trace Context and OpenTelemetry.

(2) Local logger - Elasticsearch

Distributed trace correlation is also supported out of the box by many logging providers.

For example, you can run a local Elasticsearch service to send logs to from multiple services, so they can be viewed together.

Requirements

• Dotnet 5.0
• Docker (with docker-compose), for local services

Run local Elasticsearch and Kibana

You need to be running Elasticsearch and Kibana, for example on Linux a docker compose configuration is provided. There are a number of prerequesites that you will need to meet, such as enough file handles; the elk-docker project provides a good list, including some troubleshooting (see https://elk-docker.readthedocs.io/).

For example, the most common issue is mmap count limit, which can be changed via:

echo vm.max_map_count=262144 | sudo tee -a /etc/sysctl.conf
sudo sysctl -p

Once the prerequisites are satisfied, you can bring up the docker-compose file, which will create two nodes, one for Elasticsearch and one for Kibana:

docker-compose -p demo up -d

To check the Kibana console, browse to http://localhost:5601

Add Elasticsearch

This examples uses the same components as the Basic example, a web application which then calls a back end service, but with both components sending logs to a shared Elasticsearch storage, where they can be viewed together.

The logging configuration looks like this:

Add Elasticsearch logger to app

A logger provider is available that can write directly to Elasticsearch. It can be installed via nuget, to both components:

dotnet add Demo.WebApp package Elasticsearch.Extensions.Logging --version 1.6.0-alpha1
dotnet add Demo.Service package Elasticsearch.Extensions.Logging --version 1.6.0-alpha1

To use the logger provider you need add a using statement at the top of Program.cs, in both projects:

using Elasticsearch.Extensions.Logging;

Then add a ConfigureLogging section to the host builder, in both projects:

  Host.CreateDefaultBuilder(args)
    .ConfigureLogging((hostContext, loggingBuilder) =>
    {
        loggingBuilder.AddElasticsearch();
    })
    ...

Run the two services with Elasticsearch

In separate terminals run the service:

dotnet run --project Demo.Service --urls "https://*:44301" --environment Development

And web app + api:

dotnet run --project Demo.WebApp --urls "https://*:44302" --environment Development

And check the front end at https://localhost:44302/fetch-data

View the logs

Initialise Kibana and view logs

Once you have run the application and sent some log event, you need to open Kibana (http://localhost:5601/) and initialise the database.

Navigate to Management > Index Patterns and click Create index pattern. Enter "dotnet-*" as the pattern (it should match the entries just created) and click Next step. Select the time filter "@timestamp", and click Create index pattern.

Once the index is created you can use Explore to view the log entries.

If you add the columns service.type, trace.id, and message, then you can see the messages from the web app and back end service are correlated by the trace ID.