/// <summary>
/// Observes single connector. Creates asynchronous loop.
/// </summary>
/// <param name="connector">Connector to observe.</param>
/// <param name="token">Cancellation token passed to connector.</param>
/// <remarks>See https://blogs.msdn.microsoft.com/benwilli/2016/06/30/asynchronous-infinite-loops-instead-of-timers/ for look idea description.</remarks>
/// <returns>Not used.</returns>
private async Task StartObserveSingle(ObservationConnector connector, CancellationToken token)
{
while (connector.Running)
{
try
{
if (DateTime.Now - connector.LastPoll > connector.Interval)
{
log.Log(LogLevel.Trace, "Observation of {@connector} started.", connector);
connector.LastPoll = DateTime.Now;
await connector.Connector.QueryStatus(token);
if (connector.Running)
{
this.StatusQueried?.Invoke(this, connector.Connector);
}
log.Log(LogLevel.Trace, "Observation of {@connector} ended.", connector);
}
var remainingOfInterval = connector.Interval - (DateTime.Now - connector.LastPoll);
if (remainingOfInterval.TotalMilliseconds > 0 && connector.Running)
{
int milisecondsToWait = remainingOfInterval.TotalMilliseconds < int.MaxValue ? (int)remainingOfInterval.TotalMilliseconds : int.MaxValue;
await Task.Delay(milisecondsToWait, token);
}
}
catch (Exception e)
{
log.Error(e, "Exception occurred when observing connector {connector}", new { Interval = connector.Interval, Name = connector.Connector.ConnectorConfiguration.Name, CurrentStatus = connector.Connector.CurrentStatus });
}
}
log.Log(LogLevel.Debug, "Exiting observation loop for {@connector}.", connector);
}
public void Observe(Connector connector, int interval = DefaultPollInterval)
{
if (connector == null)
{
return;
}
if (this.observedConnectors.Any(s => s.Connector.Equals(connector)))
{
// connector is already being observed
log.Warn("Connector {connector} is already being observed, skip adding.", new { Interval = interval, Name = connector.ConnectorConfiguration.Name, CurrentStatus = connector.CurrentStatus });
return;
}
var observationConnector = new ObservationConnector(connector, interval);
this.observedConnectors.Add(observationConnector);
log.Log(LogLevel.Debug, "Observation connector {@connector} added.", observationConnector);
}
