private void SubscribeToTraceSource_Initializing(object?sender, InitializingTraceSourceEventArgs e)
{
TraceSource traceSource = e.TraceSource;
if (traceSource.Name == "TraceSource_NoListeners")
{
Assert.Equal("generalSourceSwitch_Error", traceSource.Switch.DisplayName);
traceSource.Listeners.Add(new StringTraceListener());
}
}
private static void InitializingTraceSource(object sender, InitializingTraceSourceEventArgs e)
{
TraceSource traceSource = e.TraceSource;
// Ported from https://referencesource.microsoft.com/#System/compmod/system/diagnostics/TraceSource.cs,176
SourceElementsCollection sources = DiagnosticsConfiguration.Sources;
if (sources != null)
{
SourceElement sourceElement = sources[traceSource.Name];
if (sourceElement != null)
{
e.WasInitialized = true;
// First check if the type changed.
if (HasSourceSwitchTypeChanged())
{
if (!string.IsNullOrEmpty(sourceElement.SwitchName))
{
CreateSwitch(sourceElement.SwitchType, sourceElement.SwitchName);
}
else
{
CreateSwitch(sourceElement.SwitchType, traceSource.Name);
if (!string.IsNullOrEmpty(sourceElement.SwitchValue))
{
traceSource.Switch.Level = (SourceLevels)Enum.Parse(typeof(SourceLevels), sourceElement.SwitchValue);
}
}
}
else if (!string.IsNullOrEmpty(sourceElement.SwitchName))
{
// Create a new switch if the name changed, otherwise just refresh.
if (sourceElement.SwitchName != traceSource.Switch.DisplayName)
{
CreateSwitch(sourceElement.SwitchType, sourceElement.SwitchName);
}
else
{
traceSource.Switch.Refresh();
}
}
else
{
// The SwitchValue changed; just update our internalSwitch.
if (!string.IsNullOrEmpty(sourceElement.SwitchValue))
{
traceSource.Switch.Level = (SourceLevels)Enum.Parse(typeof(SourceLevels), sourceElement.SwitchValue);
}
else
{
traceSource.Switch.Level = SourceLevels.Off;
}
}
TraceListener[] newListenerCollection = new TraceListener[sourceElement.Listeners.Count];
int listnerOffset = 0;
foreach (ListenerElement listenerElement in sourceElement.Listeners)
{
TraceListener listener = traceSource.Listeners[listenerElement.Name];
if (listener != null)
{
newListenerCollection[listnerOffset++] = listenerElement.RefreshRuntimeObject(listener);
}
else
{
newListenerCollection[listnerOffset++] = listenerElement.GetRuntimeObject();
}
}
TraceUtils.CopyStringDictionary(sourceElement.Attributes, traceSource.Attributes);
traceSource.Listeners.Clear();
traceSource.Listeners.AddRange(newListenerCollection);
}
else
{
// There was no config, so clear whatever we have.
traceSource.Switch.Level = traceSource.DefaultLevel;
traceSource.Listeners.Clear();
traceSource.Attributes.Clear();
}
bool HasSourceSwitchTypeChanged()
{
string sourceTypeName = sourceElement.SwitchType;
Type currentType = traceSource.Switch.GetType();
if (string.IsNullOrEmpty(sourceTypeName))
{
// SourceSwitch is the default switch type.
return(currentType != typeof(SourceSwitch));
}
if (sourceTypeName == currentType.FullName)
{
return(false);
}
// Since there can be more than one valid AssemblyQualifiedName for a given Type this
// check can return true for some cases which can cause a minor side effect of a new
// Switch being created instead of just being refreshed.
return(sourceElement.SwitchType != currentType.AssemblyQualifiedName);
}
}
void CreateSwitch(string typeName, string name)
{
if (!string.IsNullOrEmpty(typeName))
{
traceSource.Switch = (SourceSwitch)TraceUtils.GetRuntimeObject(typeName, typeof(SourceSwitch), name);
}
else
{
traceSource.Switch = new SourceSwitch(name, traceSource.DefaultLevel.ToString());
}
}
}
