public async Task RunAsync()
{
Task backgroundService = null;
CancellationTokenSource cts = null;
bool isFirstTime = true;
try
{
while (!_ApplicationLifetimeManager.GracefulTerminationCancellationToken.IsCancellationRequested)
{
bool featureToggleValue = _FeatureToggle.IsEnabled;
if (featureToggleValue && (backgroundService is null))
{
if (!isFirstTime)
{
_Logger.LogDebug(
$"Starting background service {_TypeHelper.NameOf(_BackgroundService.GetType())} due to configuration changes");
}
cts = new CancellationTokenSource();
backgroundService = RunBackgroundService(cts.Token);
isFirstTime = false;
}
else if (!featureToggleValue && !(backgroundService is null))
{
cts.Cancel();
await backgroundService;
backgroundService = null;
cts.Dispose();
cts = null;
_Logger.LogDebug(
$"Stopped background service {_TypeHelper.NameOf(_BackgroundService.GetType())} due to configuration changes");
}
// toggle status
await Task.Delay(10000, _ApplicationLifetimeManager.GracefulTerminationCancellationToken);
}
if (backgroundService != null)
{
cts.Cancel();
await backgroundService;
_Logger.LogDebug(
$"Starting background service {_TypeHelper.NameOf(_BackgroundService.GetType())} due to application termination");
}
}
finally
{
cts?.Dispose();
}
}
public static void ServiceStopped(this ILogger logger, IBackgroundService service, TimeSpan elapsed)
{
_serviceStopped(
logger,
service.GetType().GetDisplayName(),
(long)elapsed.TotalMilliseconds);
}
public static void ServiceStopFailed(this ILogger logger, IBackgroundService service, TimeSpan elapsed, Exception exception)
{
_serviceStopFailed(
logger,
service.GetType().GetDisplayName(),
(long)elapsed.TotalMilliseconds,
exception: exception);
}
public async Task Execute(CancellationToken cancellationToken)
{
int restartCount = 0;
while (true)
{
try
{
if (restartCount > 0)
{
_Logger.LogDebug($"restart-attempt #{restartCount} for background service {_TypeHelper.NameOf(_DecoratedService.GetType())}");
}
await _DecoratedService.Execute(cancellationToken);
if (restartCount > 0)
{
_Logger.LogDebug($"background service {_TypeHelper.NameOf(_DecoratedService.GetType())} terminated normally");
}
return;
}
catch (TaskCanceledException)
{
throw;
}
catch (Exception ex)
{
_Logger.LogException(ex);
restartCount++;
TimeSpan restartDelay = GetRestartDelay(restartCount);
_Logger.LogVerbose(
$"background service {_TypeHelper.NameOf(_DecoratedService.GetType())} terminated due to an exception, restarting it in {restartDelay.Humanize()}");
await Task.Delay(restartDelay, cancellationToken).NotNull();
}
}
}
public static void ServiceStopping(this ILogger logger, IBackgroundService service)
{
_serviceStopping(logger, service.GetType().GetDisplayName());
}
