protected override async Task OnEventSourceAvailable(EventPipeEventSource eventSource, Func <Task> stopSessionAsync, CancellationToken token)
{
_trigger = Settings.TriggerFactory.Create(Settings.TriggerSettings);
_pipeline = new TraceEventTriggerPipeline(eventSource, _trigger, _callback);
await _pipeline.RunAsync(token).ConfigureAwait(false);
}
public TraceEventTriggerPipeline(TraceEventSource eventSource, ITraceEventTrigger trigger, Action <TraceEvent> callback)
{
_callback = callback ?? throw new ArgumentNullException(nameof(callback));
_eventSource = eventSource ?? throw new ArgumentNullException(nameof(eventSource));
_trigger = trigger ?? throw new ArgumentNullException(nameof(trigger));
IReadOnlyDictionary <string, IReadOnlyCollection <string> > providerEventMapFromTrigger =
_trigger.GetProviderEventMap();
if (null == providerEventMapFromTrigger)
{
// Allow all events to be forwarded to the trigger
_eventSource.Dynamic.AddCallbackForProviderEvents(
null,
TraceEventCallback);
}
else
{
// Event providers should be compared case-insensitive whereas counter names should be compared case-sensative.
// Make a copy of the provided map and change the comparers as appropriate.
IDictionary <string, IEnumerable <string> > providerEventMap = providerEventMapFromTrigger.ToDictionary(
kvp => kvp.Key,
//Accept null or empty, both indicating that any event will be accepted.
kvp => (kvp.Value == null) ? null : (kvp.Value.Count == 0) ? null : kvp.Value.ToArray().AsEnumerable(),
StringComparer.OrdinalIgnoreCase);
// Only allow events described in the mapping to be forwarded to the trigger.
// If a provider has no events specified, then all events from that provider are forwarded.
_eventSource.Dynamic.AddCallbackForProviderEvents(
(string providerName, string eventName) =>
{
if (!providerEventMap.TryGetValue(providerName, out IEnumerable <string> eventNames))
{
return(EventFilterResponse.RejectProvider);
}
else if (null == eventNames)
{
return(EventFilterResponse.AcceptEvent);
}
else if (!eventNames.Contains(eventName, StringComparer.Ordinal))
{
return(EventFilterResponse.RejectEvent);
}
return(EventFilterResponse.AcceptEvent);
},
TraceEventCallback);
}
}
