feat: change to restart timer

alejandropb36 · May 11, 2023 · 76870b4 · 76870b4
1 parent 8d935e1
commit 76870b4
Showing 1 changed file with 43 additions and 39 deletions.
diff --git a/src/SimpleCronWorkerService/CronWorkerService.cs b/src/SimpleCronWorkerService/CronWorkerService.cs
@@ -9,7 +9,7 @@ namespace SimpleCronWorkerService
 {
     public abstract class CronWorkerService : BackgroundService
     {
-        private Timer? _timer;
+        private Timer _timer;
 
         private readonly CronExpression _cronExpression;
 
@@ -24,59 +24,63 @@ public CronWorkerService(ICronWorkerServiceSettings settings)
                 : CronExpression.Parse(settings.CronExpression);
 
             _timeZone = settings.TimeZone ?? TimeZoneInfo.Utc;
+
+            _timer = new Timer
+            {
+                AutoReset = false
+            };
         }
 
         protected override async Task ExecuteAsync(CancellationToken cancellationToken)
         {
-            try
+            await RestartTimer(cancellationToken);
+
+            _timer.Elapsed += async (sender, args) =>
             {
-                var next = _cronExpression.GetNextOccurrence(DateTimeOffset.Now, _timeZone);
-                if (!next.HasValue)
+                _timer.Stop();
+
+                if (!cancellationToken.IsCancellationRequested)
                 {
-                    return;
-                }
+                    var doWorkTask = DoWork(cancellationToken);
 
-                var delay = GetDelay(next.Value);
+                    var restartTimerTask = RestartTimer(cancellationToken);
 
-                // If it is a value greater than the MaxValue of Int,
-                // we have to wait for this difference to decrease.
-                // I wait for the same amount as MaxValue minus one minute and
-                // then validate again if it could be a valid value for the Timer.
-                while (delay.TotalMilliseconds > int.MaxValue)
-                {
-                    await Task.Delay(DelayMaxValueMilliseconds, cancellationToken);
-                    delay = GetDelay(next.Value);
+                    await doWorkTask;
+                    await restartTimerTask;
                 }
+            };
 
-                if (delay.TotalMilliseconds <= 0 )
-                {
-                    await ExecuteAsync(cancellationToken);
-                    return;
-                }
+            await Task.CompletedTask;
+        }
 
-                _timer = new Timer(delay.TotalMilliseconds);
-                _timer.Elapsed += async (sender, args) =>
-                {
-                    _timer.Dispose();
-                    _timer = null;
-
-                    if (!cancellationToken.IsCancellationRequested)
-                    {
-                        var doWorkTask = DoWork(cancellationToken);
-                        var executeTask = ExecuteAsync(cancellationToken);
-
-                        await doWorkTask;
-                        await executeTask;
-                    }
-                };
-                _timer.Start();
+        private async Task RestartTimer(CancellationToken cancellationToken)
+        {
+            var next = _cronExpression.GetNextOccurrence(DateTimeOffset.Now, _timeZone);
+            if (!next.HasValue)
+            {
+                return;
             }
-            catch (OperationCanceledException)
+
+            var delay = GetDelay(next.Value);
+
+            // If it is a value greater than the MaxValue of Int,
+            // we have to wait for this difference to decrease.
+            // I wait for the same amount as MaxValue minus one minute and
+            // then validate again if it could be a valid value for the Timer.
+            while (delay.TotalMilliseconds > int.MaxValue)
             {
-                Console.WriteLine("CronWorkerService was cancelled");
+                await Task.Delay(DelayMaxValueMilliseconds, cancellationToken);
+                delay = GetDelay(next.Value);
             }
 
-            await Task.CompletedTask;
+            if (delay.TotalMilliseconds <= 0)
+            {
+                await RestartTimer(cancellationToken);
+                return;
+            }
+
+            _timer.Interval = delay.TotalMilliseconds;
+            _timer.Start();
         }
 
         private TimeSpan GetDelay(DateTimeOffset nextValue) => nextValue - DateTimeOffset.Now;