NLogTarget: How to exclude a log event property from telemetry?

[muratkuru]

• List of NuGet packages and version that you are using: Microsoft.ApplicationInsights.NLogTarget
• Runtime version (e.g. net461, net48, netcoreapp2.1, netcoreapp3.1, etc. You can find this information from the *.csproj file): netcoreapp3.1
• Hosting environment (e.g. Azure Web App, App Service on Linux, Windows, Ubuntu, etc.): Windows

What are you trying to achieve?

There is logging process like below

        private readonly ILogger<HomeController> _logger;

        public HomeController(ILogger<HomeController> logger)
        {
            _logger = logger;
        }

        [HttpGet]
        public IActionResult Get()
        {
            string request = string.Empty;
            string response = string.Empty;
            TimeSpan elapsedTime = TimeSpan.Zero;

            _logger.Log(LogLevel.Information,
                default,
                new ServiceLogEvent(request, response, elapsedTime),
                default,
                (l, e) => string.Empty);

            return NoContent();
        }

and contextproperties in nlog.config like below

      <contextproperty name="request" layout="${masked:${event-properties:Request}}"/>
      <contextproperty name="response" layout="${masked:${event-properties:Response}}"/>

These context properties (request, response) logged to Application Insights as masked as well as expected. But also there are log event properties in the log object unexpectedly.

{
    "request": "{ \"phone\": \"******\" }",
    "response": "{ \"result\": \"Some *** *** data.\" }",
    "Request": "{ \"phone\": \"1111111111\" }", 
    "Response": "{ \"result\": \"Some other sensitive data.\" }",
}

Is this a bad approach or is there any workaround?

What have you tried so far?

I am using a custom ApplicationInsightsTarget (forked from this repo) who has an ExcludeLogEventProperty property for now.

    <target 
      xsi:type="ApplicationInsightsTarget" 
      name="ApplicationInsights">
      <contextproperty name="request" layout="${masked:${event-properties:Request}}"/>
      <contextproperty name="response" layout="${masked:${event-properties:Response}}"/>
      <excludelogeventproperty name="Request" />
      <excludelogeventproperty name="Response" />
    </target>

I can open a PR for this method if it will be useful.

[github-actions]

This issue is stale because it has been open 300 days with no activity. Remove stale label or comment or this will be closed in 7 days.

[snakefoot]

Will be resolved with #2103 and updating to NLog 5.0 (See also NLog/NLog#4642)