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#72 added option to disable exception handling on idle client
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@danzuep
danzuep committed Aug 25, 2024
1 parent b5577df commit 9a0b34d
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Showing 3 changed files with 56 additions and 33 deletions.
3 changes: 2 additions & 1 deletion source/MailKitSimplified.Receiver/Abstractions/IMailFolderMonitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,7 @@ public interface IMailFolderMonitor
/// Idle client that monitors a mail folder for incoming messages.
/// </summary>
/// <param name="cancellationToken">Request cancellation token.</param>
Task IdleAsync(CancellationToken cancellationToken = default);
/// <param name="handleExceptions">Option to disable exception handling.</param>
Task IdleAsync(CancellationToken cancellationToken = default, bool handleExceptions = true);
}
}
4 changes: 2 additions & 2 deletions source/MailKitSimplified.Receiver/Models/FolderMonitorOptions.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -39,9 +39,9 @@ public class FolderMonitorOptions
public byte MaxRetries { get; set; } = 3;

/// <summary>
/// The length of time the message queues will idle for when empty.
/// The length of time the message queues will idle for when empty and retry time between attempts after an exception.
/// </summary>
public ushort EmptyQueueMaxDelayMs { get; set; } = 100;
public ushort EmptyQueueMaxDelayMs { get; set; } = 500;

public override string ToString() => $"MessageSummaryItems={MessageSummaryItems}, IgnoreExisting={IgnoreExistingMailOnConnect}, IdleMinutes={IdleMinutes}, MaxRetries={MaxRetries}.";
}
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82 changes: 52 additions & 30 deletions source/MailKitSimplified.Receiver/Services/MailFolderMonitor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -200,17 +200,16 @@ public IMailFolderMonitor OnMessageFlagsChanged(Action<IMessageSummary> messageF
return _completedTask;
});

public async Task IdleAsync(CancellationToken cancellationToken = default)
public async Task IdleAsync(CancellationToken cancellationToken = default, bool handleExceptions = true)
{
_logger.Log<MailFolderMonitor>($"{_imapReceiver} monitoring requested.", LogLevel.Trace);
_cancel = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
try
{
var tasks = new Task[]
var tasks = handleExceptions ? new Task[]
{
IdleStartAsync(_cancel.Token).ContinueWith(t =>
_logger.Log<MailFolderMonitor>(t.Exception?.GetBaseException(),
"Idle client failed."), TaskContinuationOptions.OnlyOnFaulted),
IdleStartAsync(_cancel.Token).ContinueWith((t) =>
OnIdleException(t, "Idle client failed."), TaskContinuationOptions.OnlyOnFaulted),
ProcessArrivalQueueAsync(_messageArrivalMethod, _cancel.Token).ContinueWith(t =>
_logger.Log<MailFolderMonitor>(t.Exception?.GetBaseException(),
"Arrival queue processing failed."), TaskContinuationOptions.OnlyOnFaulted),
Expand All @@ -220,21 +219,37 @@ public async Task IdleAsync(CancellationToken cancellationToken = default)
ProcessFlagChangeQueueAsync(_messageFlagsChangedMethod, _cancel.Token).ContinueWith(t =>
_logger.Log<MailFolderMonitor>(t.Exception?.GetBaseException(),
"Flag change queue processing failed."), TaskContinuationOptions.OnlyOnFaulted)
} : new Task[] {
IdleStartAsync(_cancel.Token),
ProcessDepartureQueueAsync(_messageArrivalMethod, _cancel.Token),
ProcessDepartureQueueAsync(_messageDepartureMethod, _cancel.Token),
ProcessFlagChangeQueueAsync(_messageFlagsChangedMethod, _cancel.Token)
};
await Task.WhenAll(tasks).ConfigureAwait(false);
_logger.Log<MailFolderMonitor>($"{_imapReceiver} monitoring complete.", LogLevel.Information);
}
catch (OperationCanceledException)
{
_logger.Log<MailFolderMonitor>($"{_imapReceiver} email monitoring cancelled.", LogLevel.Trace);
if (handleExceptions)
_logger.Log<MailFolderMonitor>($"{_imapReceiver} email monitoring cancelled.", LogLevel.Trace);
else
throw;
}
catch (Exception ex)
{
_logger.Log<MailFolderMonitor>(ex, $"{_imapReceiver} email monitoring failed.");
if (handleExceptions)
_logger.Log<MailFolderMonitor>(ex, $"{_imapReceiver} email monitoring failed.");
else
throw;
}

void OnIdleException(Task task, string message)
{
_logger.Log<MailFolderMonitor>(task.Exception?.GetBaseException(), message);
}
}

private async Task IdleStartAsync(CancellationToken cancellationToken = default)
private async Task IdleStartAsync(CancellationToken cancellationToken = default, bool handleExceptions = true)
{
if (_messageArrivalMethod != null && _messageDepartureMethod != null)
{
Expand All @@ -260,15 +275,18 @@ private async Task IdleStartAsync(CancellationToken cancellationToken = default)
}
catch (OperationCanceledException)
{
_logger.Log<MailFolderMonitor>("Initial fetch or idle task in mail folder monitor was cancelled.", LogLevel.Debug);
_logger.Log<MailFolderMonitor>($"{_imapReceiver} Initial fetch or idle task in mail folder monitor was cancelled.", LogLevel.Debug);
}
catch (AuthenticationException ex)
{
_logger.Log<MailFolderMonitor>(ex, "Stopping mail folder monitor service.", LogLevel.Warning);
_logger.Log<MailFolderMonitor>(ex, $"{_imapReceiver} Stopping mail folder monitor service.", LogLevel.Warning);
}
catch (InvalidOperationException ex)
{
_logger.Log<MailFolderMonitor>(ex, "IMAP client not available.", LogLevel.Error);
if (handleExceptions)
_logger.Log<MailFolderMonitor>(ex, $"{_imapReceiver} IMAP client not available.", LogLevel.Error);
else
throw;
}
finally
{
Expand All @@ -279,7 +297,7 @@ private async Task IdleStartAsync(CancellationToken cancellationToken = default)

private void Disconnect(bool throwOnFirstException)
{
_logger.Log<MailFolderMonitor>("Disconnecting IMAP idle client...", LogLevel.Trace);
_logger.Log<MailFolderMonitor>($"{_imapReceiver} Disconnecting IMAP idle client...", LogLevel.Trace);
if (_mailFolder != null)
{
_mailFolder.MessageFlagsChanged += OnFlagsChanged;
Expand Down Expand Up @@ -339,15 +357,16 @@ private async ValueTask ReconnectAsync(CancellationToken cancellationToken = def

async ValueTask LogDelayAsync(Exception exception, string exceptionType)
{
bool isBackoff = attemptCount > 0;
var backoff = isBackoff ? $", backing off for {_folderMonitorOptions.EmptyQueueMaxDelayMs}ms" : string.Empty;
var message = $"{exceptionType} during connection attempt #{++attemptCount}{backoff}. {_imapReceiver}.";
bool isBackoff = attemptCount > 0 && attemptCount < _folderMonitorOptions.MaxRetries;
var backoffDelay = _folderMonitorOptions.EmptyQueueMaxDelayMs ^ attemptCount;
var backoff = isBackoff ? $", backing off for {backoffDelay}ms" : string.Empty;
var message = $"{_imapReceiver} {exceptionType} during connection attempt #{++attemptCount}{backoff}.";
if (attemptCount < _folderMonitorOptions.MaxRetries)
_logger.Log<MailFolderMonitor>(message, LogLevel.Information);
else
_logger.Log<MailFolderMonitor>(exception, message, LogLevel.Error);
throw exception; // TODO fix this, it changes the stacktrace parameter
if (isBackoff)
await Task.Delay(_folderMonitorOptions.EmptyQueueMaxDelayMs, cancellationToken).ConfigureAwait(false);
await Task.Delay(backoffDelay, cancellationToken).ConfigureAwait(false);
}
}
}
Expand Down Expand Up @@ -377,7 +396,7 @@ private async ValueTask WaitForNewMessagesAsync(CancellationToken cancellationTo
}
catch (OperationCanceledException) // includes TaskCanceledException
{
_logger.Log<MailFolderMonitor>($"Mail folder idle wait task cancelled. {_imapReceiver}.", LogLevel.Trace);
_logger.Log<MailFolderMonitor>($"{_imapReceiver} Mail folder idle wait task cancelled.", LogLevel.Trace);
_cancel.Cancel(false);
break;
}
Expand All @@ -396,27 +415,27 @@ private async ValueTask WaitForNewMessagesAsync(CancellationToken cancellationTo
}
catch (ImapCommandException)
{
_logger.Log<MailFolderMonitor>("IMAP command exception, rechecking server connection.");
_logger.Log<MailFolderMonitor>($"{_imapReceiver} IMAP command exception, rechecking server connection.");
}
catch (IOException)
{
_logger.Log<MailFolderMonitor>("IMAP I/O exception, reconnecting.");
_logger.Log<MailFolderMonitor>($"{_imapReceiver} IMAP I/O exception, reconnecting.");
}
catch (SocketException)
{
_logger.Log<MailFolderMonitor>("IMAP socket exception, reconnecting.");
_logger.Log<MailFolderMonitor>($"{_imapReceiver} IMAP socket exception, reconnecting.");
}
catch (ServiceNotConnectedException)
{
_logger.Log<MailFolderMonitor>("IMAP service not connected, reconnecting.");
_logger.Log<MailFolderMonitor>($"{_imapReceiver} IMAP service not connected, reconnecting.");
}
catch (ServiceNotAuthenticatedException)
{
_logger.Log<MailFolderMonitor>("IMAP service not authenticated, authenticating.");
_logger.Log<MailFolderMonitor>($"{_imapReceiver} IMAP service not authenticated, authenticating.");
}
catch (InvalidOperationException ex)
{
_logger.Log<MailFolderMonitor>(ex, $"IMAP client is being accessed by multiple threads. {_imapReceiver}.");
_logger.Log<MailFolderMonitor>(ex, $"{_imapReceiver} IMAP client is being accessed by multiple threads.");
_cancel.Cancel(false);
break;
}
Expand Down Expand Up @@ -476,14 +495,15 @@ private async Task ProcessArrivalQueueAsync(Func<IMessageSummary, Task> messageA
}
catch (OperationCanceledException)
{
_logger.Log<MailFolderMonitor>("Arrival queue cancelled.", LogLevel.Trace);
_logger.Log<MailFolderMonitor>($"{_imapReceiver} Arrival queue cancelled.", LogLevel.Trace);
break;
}
catch (Exception ex)
{
if (messageSummary != null)
_arrivalQueue.Enqueue(messageSummary);
_logger.Log<MailFolderMonitor>(ex, $"Error occurred processing arrival queue item during attempt #{retryCount}, backing off for {_folderMonitorOptions.EmptyQueueMaxDelayMs}ms. {_imapReceiver} #{messageSummary?.UniqueId}.", LogLevel.Warning);
var backoff = _folderMonitorOptions.EmptyQueueMaxDelayMs ^ retryCount;
_logger.Log<MailFolderMonitor>(ex, $"{_imapReceiver} Error occurred processing arrival queue item ({messageSummary?.UniqueId}) during attempt #{retryCount}, backing off for {backoff}ms.", LogLevel.Warning);
await Task.Delay(_folderMonitorOptions.EmptyQueueMaxDelayMs, cancellationToken).ConfigureAwait(false);
}
}
Expand All @@ -510,14 +530,15 @@ private async Task ProcessDepartureQueueAsync(Func<IMessageSummary, Task> messag
}
catch (OperationCanceledException)
{
_logger.Log<MailFolderMonitor>("Departure queue cancelled.", LogLevel.Trace);
_logger.Log<MailFolderMonitor>($"{_imapReceiver} Departure queue cancelled.", LogLevel.Trace);
break;
}
catch (Exception ex)
{
if (messageSummary != null)
_departureQueue.Enqueue(messageSummary);
_logger.Log<MailFolderMonitor>(ex, $"Error occurred processing departure queue item during attempt #{retryCount}, backing off for {_folderMonitorOptions.EmptyQueueMaxDelayMs}ms. {_imapReceiver} #{messageSummary?.UniqueId}.", LogLevel.Warning);
var backoff = _folderMonitorOptions.EmptyQueueMaxDelayMs ^ retryCount;
_logger.Log<MailFolderMonitor>(ex, $"{_imapReceiver} Error occurred processing departure queue item ({messageSummary?.UniqueId}) during attempt #{retryCount}, backing off for {backoff}ms.", LogLevel.Warning);
await Task.Delay(_folderMonitorOptions.EmptyQueueMaxDelayMs, cancellationToken).ConfigureAwait(false);
}
}
Expand Down Expand Up @@ -551,14 +572,15 @@ private async Task ProcessFlagChangeQueueAsync(Func<IMessageSummary, Task> messa
}
catch (OperationCanceledException)
{
_logger.Log<MailFolderMonitor>("Flag change queue cancelled.", LogLevel.Trace);
_logger.Log<MailFolderMonitor>($"{_imapReceiver} Flag change queue cancelled.", LogLevel.Trace);
break;
}
catch (Exception ex)
{
if (messageSummary != null)
_flagChangeQueue.Enqueue(messageSummary);
_logger.Log<MailFolderMonitor>(ex, $"Error occurred processing flag change queue item during attempt #{retryCount}, backing off for {_folderMonitorOptions.EmptyQueueMaxDelayMs}ms. {_imapReceiver} #{messageSummary?.UniqueId}.", LogLevel.Warning);
var backoff = _folderMonitorOptions.EmptyQueueMaxDelayMs ^ retryCount;
_logger.Log<MailFolderMonitor>(ex, $"{_imapReceiver} Error occurred processing flag change queue item ({messageSummary?.UniqueId}) during attempt #{retryCount}, backing off for {backoff}ms.", LogLevel.Warning);
await Task.Delay(_folderMonitorOptions.EmptyQueueMaxDelayMs, cancellationToken).ConfigureAwait(false);
}
}
Expand Down

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