/// <summary>
/// Stops active trace:
/// - Cancels BG polling loop
/// - Closes DB reader
/// - Unregisters trace
/// - Closes DB connection
/// </summary>
/// <param name="cancel"></param>
/// <returns></returns>
public async Task StopTraceSessionAsync(CancellationToken cancel)
{
Log.Debug("Stopping trace session");
// cancel active readers
_readerCancel.Cancel();
try
{
await _traceReader.CloseDbReaderAsync(cancel);
}
catch
{
Log.Warn("Cannot close DB reader");
}
cancel.ThrowIfCancellationRequested();
try
{
await _traceReader.UnregisterTraceAsync(cancel);
}
catch
{
Log.Warn("Cannot unregister DB trace");
}
Log.Debug("Terminating connection");
_connection.Close();
_connection = null;
_traceReader = null;
Log.Debug("Trace stopped");
}
/// <summary>
/// - Connects to DB
/// - Registers events
/// - Opens DB reader
/// - Starts trace reader BG polling event
/// </summary>
public async Task StartTraceSessionAsync(ServerConnection connection, Dictionary <EventClassType, List <EventColumnType> > registeredEvents, CancellationToken cancel)
{
Log.Info("Starting trace session");
try
{
_connection = await new DbConnection().GetNewConnectionAsync(connection, cancel);
}
catch
{
Log.Warn("Error opening connection");
throw;
}
cancel.ThrowIfCancellationRequested();
try
{
_traceReader = new TraceReader(_connection);
await _traceReader.RegisterTraceAsync(registeredEvents, cancel);
}
catch
{
Log.Warn("Could not register trace/events. Closing connection.");
_connection.Dispose();
_connection = null;
_traceReader = null;
throw;
}
cancel.ThrowIfCancellationRequested();
try
{
await _traceReader.OpenDbReaderAsync(cancel);
}
catch
{
Log.Warn("Could not open DB reader");
await _traceReader.UnregisterTraceAsync(cancel);
_connection.Dispose();
_connection = null;
_traceReader = null;
throw;
}
cancel.ThrowIfCancellationRequested();
try
{
Log.Debug("Starting BG thread");
_readerCancel = new CancellationTokenSource();
// start background thread (without "await", to keep it running)
var progress = new Progress <Tuple <ProfilerEventStatus, ProfilerEvent> >(p => OnEvent?.Invoke(p.Item1, p.Item2));
var _ = _traceReader.BackgroundPollingThreadAsync(_readerCancel.Token, progress);
}
catch (Exception ex)
{
Log.Error("Error starting BG worker", ex);
throw;
}
}