Transforming ApplicationInsights.config depending on build-configuration

Because I wanted to configure adaptive sampling only for my release-configuration in the production environment I wondered whether it is possible to transform ApplicationInsights.config similar to transforming web.config in Web-projects.

Turned out that this can be achieved by using the XML-Document-Transform namespace, which is mapped to the xdt prefix.

For each build-configuration I added an ApplicationInsights.<build-configuration>.config file.

My build-configurations are:

• Debug_PROD
• Debug_TEST
• Release_PROD
• Release_TEST

resulting in the following ApplicationInsights-config-files:

• ApplicationInsights.Debug_PROD.config
• ApplicationInsights.Debug_TEST.config
• ApplicationInsights.Release_PROD.config
• ApplicationInsights.Release_TEST.config

The TelemetrySinks-element of my ApplicationInsights.config looks like this:

<TelemetrySinks>
    <Add Name="default">
      <TelemetryProcessors>
        <Add Type="Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector.QuickPulse.QuickPulseTelemetryProcessor, Microsoft.AI.PerfCounterCollector"/>
        <Add Type="Microsoft.ApplicationInsights.Extensibility.AutocollectedMetricsExtractor, Microsoft.ApplicationInsights"/>
      </TelemetryProcessors>
      <TelemetryChannel Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.ServerTelemetryChannel, Microsoft.AI.ServerTelemetryChannel"/>
    </Add>
</TelemetrySinks>

For my ApplicationInsights.Release_PROD.config I used the following transformation, which adds adaptive sampling and reduces the transmitted telemetry items to 5 per second:

<?xml version="1.0"?>
<!-- For more information on using app.config transformation visit http://go.microsoft.com/fwlink/?LinkId=125889 -->
<!-- In case configuration is not the root element, replace it with root element in source configuration file -->
<ApplicationInsights xmlns="http://schemas.microsoft.com/ApplicationInsights/2013/Settings" xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform">
  <TelemetrySinks>
    <Add Name="default">
      <TelemetryProcessors>
        <Add Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.AdaptiveSamplingTelemetryProcessor, Microsoft.AI.ServerTelemetryChannel" xdt:Transform="Insert">
          <MaxTelemetryItemsPerSecond>5</MaxTelemetryItemsPerSecond>
        </Add>
      </TelemetryProcessors>
    </Add>
  </TelemetrySinks>
</ApplicationInsights>

The resulting TelemetrySinks-element of my ApplicationInsights.config looks like this:

<TelemetrySinks>
    <Add Name="default">
      <TelemetryProcessors>
        <Add Type="Microsoft.ApplicationInsights.Extensibility.PerfCounterCollector.QuickPulse.QuickPulseTelemetryProcessor, Microsoft.AI.PerfCounterCollector"/>
        <Add Type="Microsoft.ApplicationInsights.Extensibility.AutocollectedMetricsExtractor, Microsoft.ApplicationInsights"/>
		<Add Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.AdaptiveSamplingTelemetryProcessor, Microsoft.AI.ServerTelemetryChannel">
          <MaxTelemetryItemsPerSecond>5</MaxTelemetryItemsPerSecond>
        </Add>
      </TelemetryProcessors>
      <TelemetryChannel Type="Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.ServerTelemetryChannel, Microsoft.AI.ServerTelemetryChannel"/>
    </Add>
</TelemetrySinks>

To run the transformation during the build-process I created the following target in my csproj-file:

<Target Name="TransformApplicationInsights_AfterCopyApplicationInsightsConfigToOutputDirectory" AfterTargets="CopyApplicationInsightsConfigToOutputDirectory" Condition="Exists('ApplicationInsights.$(Configuration).config')">
    <Message Text="Transforming ApplicationInsights.config to bin\$(Configuration)\ApplicationInsights.config after CopyApplicationInsightsConfigToOutputDirectory using ApplicationInsights.$(Configuration).config" Importance="high" />
    <TransformXml Source="ApplicationInsights.config" Transform="ApplicationInsights.$(Configuration).config" Destination="bin\$(Configuration)\ApplicationInsights.config" />
</Target>

It’s important to use the rarely documented “CopyApplicationInsightsConfigToOutputDirectory” target for the AfterTargets-setting to avoid your transformed ApplicationInsights.config to be overwritten with the original one by the build process.

Have fun!