public static void Explain(this UnobservedException runnable, TextWriter writer)
{
writer.WriteLine(@"
- Async void methods will crash the process if an exception is thrown
- `Task`-returning methods are better since unhandled exceptions trigger the `TaskScheduler.UnobservedTaskException`
- Be ware that only when the finalizers are run the unobserved exception is thrown
");
}
private void onUnobservedException(Exception e)
{
if (Debugger.IsAttached)
{
Debugger.Break();
}
var eventArgs = new UnobservedTaskExceptionEventArgs(new AggregateException(e));
UnobservedException?.Invoke(this, eventArgs);
if (!eventArgs.Observed)
{
Environment.FailFast("Unobserved exception in Dbus handling", e);
}
}
public static void Explain(this UnobservedException runnable, TextWriter writer)
{
writer.WriteLine(@"
- Only when the finalizers are run the unobserved exception is thrown
");
}
private async Task ExecuteOnceAsync(CancellationToken token)
{
var taskFactory = new TaskFactory(TaskScheduler.Current);
// Cached since this will be referenced quite frequently in this method
var referenceTime = DateTime.Now;
// Determine which tasks will never run again and remove them from the database
var removeList = _scheduledTasks.Where(x => x.Value.WillNeverRunAgain).ToList();
// We must ensure that our database is updated -- to remove tasks that will never run again
using (DevryDbContext context = new DevryDbContext())
{
foreach (var pair in removeList)
{
Models.Reminder reminder = await context.Reminders.FindAsync(pair.Key);
if (reminder == null)
{
_logger.LogWarning($"Unable to locate reminder with Id: {pair.Key}");
continue;
}
else
{
_logger.LogInformation($"Reminder: '{reminder.Name}' with Id '{reminder.Id}' is being cleaned up. --Determined to never run again");
context.Reminders.Remove(reminder);
_scheduledTasks.Remove(pair.Key);
}
}
// Save changes (if applicable)
await context.SaveChangesAsync();
}
var tasksThatShouldRun = _scheduledTasks.Values.Where(x => x.ShouldRun(referenceTime));
foreach (var task in tasksThatShouldRun)
{
task.Increment();
await taskFactory.StartNew(
async() =>
{
try
{
await task.Task.ExecuteAsync(token);
}
catch (Exception ex)
{
var args = new UnobservedTaskExceptionEventArgs(ex as AggregateException ?? new AggregateException(ex));
UnobservedException?.Invoke(this, args);
if (!args.Observed)
{
throw;
}
}
},
token);
}
}
