opentelemetry-dotnet/docs/logs/correlation/README.md

Correlate Logs with Traces

Starting from Microsoft.Extensions.Logging version 5.0, logs can be correlated with distributed tracing by enriching each log entry with the information from the enclosing Activity. This can be achieved by enabling the ActivityTrackingOptions. In a non-host console app, it can be achieved as shown below.

using var loggerFactory = LoggerFactory.Create(builder =>
{
    builder.Configure(options => options.ActivityTrackingOptions =
        ActivityTrackingOptions.TraceId |
        ActivityTrackingOptions.SpanId);
});

Please refer to the example here.

In an ASP.NET Core app, the above can be achieved by modifying the host building, as shown below.

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .ConfigureLogging(loggingBuilder =>
            loggingBuilder.Configure(options =>
                options.ActivityTrackingOptions =
                    ActivityTrackingOptions.TraceId
                    | ActivityTrackingOptions.SpanId))
        .ConfigureWebHostDefaults(webBuilder =>
        {
            webBuilder.UseStartup<Startup>();
        });

Microsoft.Extensions.Logging.ActivityTrackingOptions supports TraceId, SpanId, ParentId, TraceFlags and TraceState.

References

• ILogger
• Microsoft.Extensions.Logging