我一直在关注Service Fabric中的有状态服务.我一直在挖掘这些例子,特别是WordCount.他们有一个RunAsync方法,在WordCountService中看起来像这样:
protected override async Task RunAsync(CancellationToken cancellationToken)
{
IReliableQueue<string> inputQueue = await this.StateManager.GetOrAddAsync<IReliableQueue<string>>("inputQueue");
while (true)
{
cancellationToken.ThrowIfCancellationRequested();
try
{
using (ITransaction tx = this.StateManager.CreateTransaction())
{
ConditionalValue<string> dequeuReply = await inputQueue.TryDequeueAsync(tx);
if (dequeuReply.HasValue)
{
//... {more example code here }
}
await Task.Delay(TimeSpan.FromMilliseconds(100), cancellationToken);
}
catch (TimeoutException)
{
//Service Fabric uses timeouts on collection operations to prevent deadlocks.
//If this exception is thrown, it means that this transaction was waiting the default
//amount of time (4 seconds) but was unable to acquire the lock. In this case we simply
//retry after a random backoff interval. You can also control the timeout via a parameter
//on the collection operation.
Thread.Sleep(TimeSpan.FromSeconds(new Random().Next(100, 300)));
continue;
}
catch (Exception exception)
{
//For sample code only: simply trace the exception.
ServiceEventSource.Current.MessageEvent(exception.ToString());
}
}
}
本质上,在此示例中,服务每隔100毫秒轮询一次ReliableQueue消息.没有民意调查,有没有办法做到这一点?当消息成功添加到ReliableQueue时,我们可以订阅事件或触发的事件吗?
最佳答案 不,目前没有可用于ReliableQueue的活动.您必须轮询新项目.