Enhance logging in recurring tasks: add error handling and logger support to prevent crashes in scheduled timers.

Author: sfmskywalker

src/modules/Elsa.Common/Multitenancy/EventHandlers/TenantTaskManager.cs

@@ -118,7 +118,12 @@ private async Task StartRecurringTasksAsync(ITenantScope tenantScope, ITaskExecu
                 {
                     logger.LogInformation(e, "Recurring task {TaskType} was cancelled", task.GetType().Name);
                 }
-            });
+                catch (Exception e)
+                {
+                    // Log but don't rethrow - recurring tasks should not crash the host
+                    logger.LogError(e, "Recurring task {TaskType} failed with an error", task.GetType().Name);
+                }
+            }, logger);
 
             _scheduledTimers.Add(timer);
             await task.StartAsync(cancellationToken);

src/modules/Elsa.Common/RecurringTasks/CronSchedule.cs

@@ -1,11 +1,12 @@
 using Cronos;
+using Microsoft.Extensions.Logging;
 
 namespace Elsa.Common.RecurringTasks;
 
 public class CronSchedule(ISystemClock systemClock, CronExpression expression) : ISchedule
 {
-    public ScheduledTimer CreateTimer(Func<Task> action)
+    public ScheduledTimer CreateTimer(Func<Task> action, ILogger? logger = null)
     {
-        return new ScheduledTimer(action, () => expression.GetNextOccurrence(systemClock.UtcNow.DateTime)!.Value - systemClock.UtcNow.DateTime);
+        return new ScheduledTimer(action, () => expression.GetNextOccurrence(systemClock.UtcNow.DateTime)!.Value - systemClock.UtcNow.DateTime, logger);
     }
 }

src/modules/Elsa.Common/RecurringTasks/ISchedule.cs

@@ -1,6 +1,8 @@
+using Microsoft.Extensions.Logging;
+
 namespace Elsa.Common.RecurringTasks;
 
 public interface ISchedule
 {
-    ScheduledTimer CreateTimer(Func<Task> action);
+    ScheduledTimer CreateTimer(Func<Task> action, ILogger? logger = null);
 }

src/modules/Elsa.Common/RecurringTasks/IntervalSchedule.cs

@@ -1,9 +1,11 @@
+using Microsoft.Extensions.Logging;
+
 namespace Elsa.Common.RecurringTasks;
 
 public class IntervalSchedule(TimeSpan interval) : ISchedule
 {
-    public ScheduledTimer CreateTimer(Func<Task> action)
+    public ScheduledTimer CreateTimer(Func<Task> action, ILogger? logger = null)
     {
-        return new ScheduledTimer(action, () => interval);
+        return new ScheduledTimer(action, () => interval, logger);
     }
 }

src/modules/Elsa.Common/RecurringTasks/ScheduledTimer.cs

@@ -1,22 +1,45 @@
+using Microsoft.Extensions.Logging;
+
 namespace Elsa.Common.RecurringTasks;
 
 public class ScheduledTimer : IDisposable, IAsyncDisposable
 {
     private readonly Func<Task> _action;
     private readonly Func<TimeSpan> _interval;
     private readonly Timer _timer;
+    private readonly ILogger? _logger;
 
-    public ScheduledTimer(Func<Task> action, Func<TimeSpan> interval)
+    public ScheduledTimer(Func<Task> action, Func<TimeSpan> interval, ILogger? logger = null)
     {
         _action = action;
         _interval = interval;
+        _logger = logger;
         _timer = new Timer(Callback, null, interval(), Timeout.InfiniteTimeSpan);
     }
 
     private async void Callback(object? state)
     {
-        await _action();
-        _timer.Change(_interval(), Timeout.InfiniteTimeSpan);
+        try
+        {
+            await _action();
+        }
+        catch (Exception e)
+        {
+            // Swallow exception to prevent async void from crashing the process.
+            // Log unhandled exceptions here as a safeguard; calling code may have its own exception handling.
+            _logger?.LogError(e, "Unhandled exception in scheduled timer action");
+        }
+        finally
+        {
+            try
+            {
+                _timer.Change(_interval(), Timeout.InfiniteTimeSpan);
+            }
+            catch (ObjectDisposedException)
+            {
+                // Timer was disposed, ignore.
+            }
+        }
     }
 
     public void Dispose()