static void Main(string[] args)
{
// there settings should be in app settings
var exceptionBehavior = DequeueExceptionBehavior.ThrowAfterProcessSuccessMessages;
bool byPassIfError = true;
TimeSpan outOfMessageDelay = TimeSpan.FromSeconds(30);
Console.WriteLine("batch fetching, please wait...");
Console.WriteLine("------------------------------");
var cleanMessages = new List <IFetchedMessage>();
while (true)
{
var canBeOutOfMessages = false;
try
{
// make sure that we cleaned up store
cleanMessages = new List <IFetchedMessage>();
var messages = _messageQueue.DequeueList(QUEUE_NAME, 10, _token);
canBeOutOfMessages = messages.Any(x => x.DequeueResultStatus != DequeueResultStatus.Success);
var firstErrorMessage = messages.FirstOrDefault(x => x.DequeueResultStatus == DequeueResultStatus.Exception);
if (firstErrorMessage != null && exceptionBehavior == DequeueExceptionBehavior.ThrowImmediately)
{
throw firstErrorMessage.DequeueException;
}
else
{
//transaction store
cleanMessages = messages.Where(x => x.DequeueResultStatus == DequeueResultStatus.Success).ToList();
// product store
var batchProducts = new List <ProductMessage>();
// parse
foreach (var item in cleanMessages)
{
if (item.Result is ProductMessage prod)
{
batchProducts.Add(prod);
}
else
{
// invaild message (which did not match any type)
throw new Exception("Invaild message");
}
}
#region This block should be in transaction
// demo bulk import
if (batchProducts.Any())
{
_fakeDatabase.AddRange(batchProducts);
}
// commit
foreach (var msg in cleanMessages)
{
msg?.Commit();
msg.Dispose();
}
Console.WriteLine($"Total records in DB: { _fakeDatabase.Count}");
#endregion
// ThrowFailureMessage
if (firstErrorMessage != null && exceptionBehavior == DequeueExceptionBehavior.ThrowAfterProcessSuccessMessages)
{
throw firstErrorMessage.DequeueException;
}
}
Console.WriteLine("-------O-K-------");
}
catch (Exception ex)
{
foreach (var msg in cleanMessages)
{
try
{
if (byPassIfError)
{
msg?.Commit();
}
else
{
msg?.Abort();
}
msg?.Dispose();
}
catch { }
}
if (!byPassIfError)
{
Console.WriteLine($"{ex.Message}\nConsumer will be stopped !!!");
break;
}
}
// if has error or timeout then wait a bit
if (canBeOutOfMessages)
{
Thread.Sleep(outOfMessageDelay);
}
Thread.Sleep(5);
}
Console.WriteLine("stopped");
Console.ReadKey();
}