Custom logging to app insights from .net core

Question

I'm using App Insights in a .net core web app and I can successfully see the telemetry data in the app insights logs. I would now like to be able to push up my own log events, but cannot seem to get it to work (i.e. my custom log events do not appear in app insights). My code is as follows:

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    loggerFactory.AddApplicationInsights(app.ApplicationServices);
    loggerFactory.AddDebug();

    var logger = loggerFactory.CreateLogger<Startup>();

    logger.LogInformation("I am a log event");

I've also tried setting the log level explicitly like:

loggerFactory.AddApplicationInsights(app.ApplicationServices, LogLevel.Debug);

But I never see the text "I am a log event" in app insights.

Can anyone tell me how I can fix this?

Answer 1

1. You need to add an Application Insights log capture module for that. Select the appropriate package - one of:
   • Microsoft.ApplicationInsights.TraceListener (to capture System.Diagnostics.Trace calls)
   • Microsoft.ApplicationInsights.EventSourceListener (to capture EventSource events)
   • Microsoft.ApplicationInsights.EtwListener (to capture ETW events)
   • Microsoft.ApplicationInsights.NLogTarget
   • Microsoft.ApplicationInsights.Log4NetAppender

Documentation section: Explore .NET trace logs in Application Insights

2. Also, you may use TelemetryClient directly. It has more options, not only TrackTrace that is used by loggers.

//TelemetryClient telemetryClient = new Microsoft.ApplicationInsights.TelemetryClient();
...
telemetryClient.TrackEvent("<EventName>");
telemetryClient.TrackMetric("<metric name>", 1);
telemetryClient.TrackTrace("message", SeverityLevel.Information);

Documentation section: Application Insights API for custom events and metrics

For the live example, you may look into feature test int ApplicationInsights-aspnetcore repo.