/// <summary>
/// The function that needs to be called before sending a request to the server. Creates and initializes dependency telemetry item.
/// </summary>
/// <param name="telemetryClient">Telemetry client object to initialize the context of the telemetry item.</param>
internal static DependencyTelemetry BeginTracking(TelemetryClient telemetryClient)
{
var telemetry = new DependencyTelemetry();
telemetry.Start();
telemetryClient.Initialize(telemetry);
#if NET45
Activity activity;
Activity currentActivity = Activity.Current;
// On .NET46 without profiler, outgoing requests are instrumented with reflection hook in DiagnosticSource
//// see https://github.com/dotnet/corefx/blob/master/src/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/HttpHandlerDiagnosticListener.cs
// it creates an Activity and injects standard 'Request-Id' and 'Correlation-Context' headers itself, so we should not start Activity in this case
if (currentActivity != null && currentActivity.OperationName == "System.Net.Http.Desktop.HttpRequestOut")
{
activity = currentActivity;
}
else
{
// Every operation must have its own Activity
// if dependency is tracked with profiler of event source, we need to generate a proper hierarchical Id for it
// in case of HTTP it will be propagated into the requert header.
// So, we will create a new Activity for the dependency, jut to generate an Id.
activity = new Activity(DependencyActivityName);
// This is workaround for the issue https://github.com/Microsoft/ApplicationInsights-dotnet/issues/538
// if there is no parent Activity, ID Activity generates is not random enough to work well with
// ApplicationInsights sampling algorithm
// This code should go away when Activity is fixed: https://github.com/dotnet/corefx/issues/18418
if (Activity.Current == null)
{
activity.SetParentId(telemetry.Id);
}
//// end of workaround
activity.Start();
activity.Stop();
}
// telemetry is initialized from current Activity (root and parent Id, but not the Id)
telemetry.Id = activity.Id;
// set operation root Id in case there was no parent activity (e.g. HttpRequest in background thread)
if (string.IsNullOrEmpty(telemetry.Context.Operation.Id))
{
telemetry.Context.Operation.Id = activity.RootId;
}
#else
// telemetry is initialized by Base SDK OperationCorrealtionTelemetryInitializer
// however it does not know about Activity on .NET40 and does not know how to properly generate Ids
// let's fix it
telemetry.Id = ApplicationInsightsActivity.GenerateDependencyId(telemetry.Context.Operation.ParentId);
telemetry.Context.Operation.Id = ApplicationInsightsActivity.GetRootId(telemetry.Id);
#endif
PretendProfilerIsAttached = false;
return(telemetry);
}
public void RddTestHttpDesktopProcessingFrameworkOnBeginAddsParentIdHeader()
{
var request = WebRequest.Create(this.testUrl);
Assert.IsNull(request.Headers[RequestResponseHeaders.StandardParentIdHeader]);
var client = new TelemetryClient(this.configuration);
using (var op = client.StartOperation <RequestTelemetry>("request"))
{
this.httpDesktopProcessingFramework.OnBegin(request);
var actualParentIdHeader = request.Headers[RequestResponseHeaders.StandardParentIdHeader];
var actualRequestIdHeader = request.Headers[RequestResponseHeaders.RequestIdHeader];
Assert.IsNotNull(actualParentIdHeader);
Assert.AreNotEqual(actualParentIdHeader, op.Telemetry.Context.Operation.Id);
Assert.AreEqual(actualParentIdHeader, actualRequestIdHeader);
#if NET45
Assert.IsTrue(actualRequestIdHeader.StartsWith(Activity.Current.Id, StringComparison.Ordinal));
Assert.AreNotEqual(Activity.Current.Id, actualRequestIdHeader);
#else
Assert.AreEqual(op.Telemetry.Context.Operation.Id, ApplicationInsightsActivity.GetRootId(request.Headers[RequestResponseHeaders.StandardParentIdHeader]));
#endif
// This code should go away when Activity is fixed: https://github.com/dotnet/corefx/issues/18418
// check that Ids are not generated by Activity
// so they look like OperationTelemetry.Id
var operationId = op.Telemetry.Context.Operation.Id;
// length is like default RequestTelemetry.Id length
Assert.AreEqual(new DependencyTelemetry().Id.Length, operationId.Length);
// operationId is ulong base64 encoded
byte[] data = Convert.FromBase64String(operationId);
Assert.AreEqual(8, data.Length);
BitConverter.ToUInt64(data, 0);
// does not look like root Id generated by Activity
Assert.AreEqual(1, operationId.Split('-').Length);
//// end of workaround test
}
}