Synchronization-Thread with Server every 5 secs

Question

I have a server-client environment, where the client connects and synchronizes data with the server every 5 second.

For synchronizing I use a background thread on the client which works fine, but on one specific hardware the method GetNetworkAvailable throws out of memory exceptions occasionaly. The errors occur whitout logic, so I guess somethings just not good with this hardware. Anyways I'd like to get your opinion on my background - polling function.

private void SynchronizedWorker()
{
 bool initialization = true;
 int initializationTries = 0;
 // Sync loop
 while (!_shouldStop)
 {
 // Initialize locals
 int syncInterval = _syncInterval; // Reset Sync Interval to default
 SyncStatus syncStatus = SyncStatus; // Get current Status
 bool hasNetworkConnection = true; // Has Network connection
 try
 {
 //*******************************************
 // Check Network connection
 //*******************************************
 if (!NetworkInterface.GetIsNetworkAvailable())
 {
 hasNetworkConnection = false;
 _syncResetEvent.Set();
 syncStatus = SyncStatus.Offline;
 }
 else if (syncStatus == SyncStatus.Offline) // Is in offline - State, but Network available again recognize going online
 {
 _syncResetEvent.Set();
 hasNetworkConnection = IsServiceAvailable();
 // Sync-Status stays offline
 if (!hasNetworkConnection)
 {
 // Wait 1 minute, before retry
 syncInterval = 60000;
 }
 }
 //*******************************************
 // Proceed with Syncronisation
 //*******************************************
 if (hasNetworkConnection)
 {
 syncStatus = SyncStatus.Ok;
 // Try Initialization
 if (initialization)
 {
 try
 {
 // Sync initialization here...
 // ..............................
 ////////////////////////////////////
 }
 catch (Exception ex)
 {
 log.LogError(string.Format("Initialization Try {0}", initializationTries), ex);
 syncStatus = SyncStatus.InitializationFailed;
 }
 }
 // To many Init-Tries --> Stop
 if (initializationTries > 1)
 {
 // Proceed
 _syncResetEvent.Set();
 _syncStatus = syncStatus;
 break; // Stop Synch
 }
 // Debug
 var sw = System.Diagnostics.Stopwatch.StartNew();
 // Do Up/Download
 if (!initialization)
 {
 try
 {
 // Synchronisation with service here...
 // ..............................
 ////////////////////////////////////
 // Proceed
 _syncResetEvent.Set();
 }
 catch (Exception ex)
 {
 log.LogError("Download", ex);
 syncStatus = SyncStatus.SynchFailed;
 }
 }
 }
 // Set Sync status
 _syncStatus = syncStatus;
 }
 catch (Exception ex)
 {
 log.LogError("Sync-Worker", ex);
 _syncStatus = Core.Sync.SyncStatus.SynchFailed;
 // Proceed
 _syncResetEvent.Set();
 // Reset Force
 _syncForce = false;
 }
 finally
 {
 // Set Completed
 if (OnSyncCompleted != null)
 {
 OnSyncCompleted(downloaded, uploaded, executed);
 }
 // Always Wait for Interval
 DateTime sleepuntil = DateTime.Now.AddMilliseconds(syncInterval);
 while (sleepuntil > DateTime.Now && !_shouldStop && !_syncForce)
 {
 // Sleep
 Thread.Sleep(100);
 }
 }
 }
 // Stop
 _syncStatus = SyncStatus.Unknown;
 }

Answer 1

1. I would do the waiting for interval at the end also with an event - I find it cleaner. Something like this:

   AutoResetEvent _syncWaitEvent = new AutoResetEvent(false);
   ....
   // I assume there is a way for external callers to stop sync
   public void StopSync()
   {
    _syncForce= true;
    _syncWaitEvent.Set();
   }
   public void ForceSync()
   {
    _shouldStop = true;
    _syncWaitEvent.Set();
   }
   private void SynchronizedWorker()
   {
    ....
    // Sync loop
    while (!_shouldStop)
    {
    ....
    // wait for next interval or being woken up
    if (_syncWaitEvent.WaitOne(syncInterval))
    {
    // we have been signaled prior to the timeout expiring
    _syncForce = false;
    }
    }
   }
   

2. I would change syncInterval to a TimeSpan (WaitOne() expects one anyway and I don't like passing values around with implicit units. Just gets you in trouble some day)

3. It's not clear from your code what the _syncResetEvent() is used for. It's seems to be called in pretty much every case. You might want to revisit the name of it.

4. Add a log message in the if (initializationTries > 1) block to state that you are stopping sync because init failed too many times.