/// <summary>
/// This action runs in the background and uploads the items in the local queue
/// to an azure queue
/// </summary>
private void UploadItems()
{
var batch = new AnalyticsItemList();
while (true)
{
try
{
AnalyticsItem item;
if (this.localQueue.TryDequeue(out item))
{
batch.Add(item);
if (batch.Count >= BatchSize)
{
SaveBatch(batch);
}
}
else
{
SaveBatch(batch);
// not a lot of items in the queue. sleep for one second
Thread.Sleep(1000);
}
// update counter to indicate currentq ueue length
Counter.SetValue(CounterNames.AnalyticsLocalQueueLength, this.localQueue.Count);
}
catch (ThreadAbortException)
{
break;
}
catch (Exception ex)
{
// never exit
Log.Error(ex, "Error saving analytics batch");
}
}
}
/// <summary>
/// Parse a list of items form an Xml String
/// </summary>
/// <param name="str">
/// the input string
/// </param>
/// <returns>
/// a list of items
/// </returns>
public static AnalyticsItemList Deserialize(string str)
{
try
{
var serializerSettings = new JsonSerializerSettings
{
NullValueHandling = NullValueHandling.Ignore
};
return(JsonConvert.DeserializeObject <AnalyticsItemList>(str, serializerSettings));
}
catch (Exception e)
{
Log.Verbose("Original String:{0}; Error: {1}", str, e);
//Don't do anything this is expected until all the systems will migrate to json
}
// Backward compatability to xml
var list = new AnalyticsItemList();
try
{
XElement document = XElement.Parse(str);
foreach (XElement node in document.Elements())
{
AnalyticsItem item = AnalyticsItem.Parse(node);
if (item != null)
{
list.Add(item);
}
}
}
catch (Exception e)
{
// log and ignore the invalid message
Log.Error(e, "Original String:{0}", str);
}
return(list);
}
/// <summary>
/// Saves a batch to the local azure queue
/// </summary>
/// <param name="batch">
/// a lits of items to be logged
/// </param>
private void SaveBatch(AnalyticsItemList batch)
{
try
{
if (batch == null)
{
Log.Error("AnalyticsClient.SaveBatch() called with null batch parameter.");
return;
}
if (batch.Count == 0)
{
return;
}
Counter.SetValue(CounterNames.AnalyticsAzureBatchSize, batch.Count);
// Enqueue to azure Queue
string message = batch.ToJsonString();
Task enqueueTask = queue.EnqueueAsync(new CloudQueueMessage(message));
Counter.Increment(CounterNames.AnalyticsLocalQueuePerSec);
enqueueTask.ContinueWith(
contTask =>
{
if (contTask.Exception != null && contTask.Exception.InnerException is StorageException)
{
EnqueueOperationOperationRateLogger.Failure(EventCode.AnalyticsClientStorageError, contTask.Exception.InnerException, "Error enqueuing item to azure queue");
}
else if (contTask.Exception != null)
{
Log.Error(EventCode.AnalyticsClientUnexpectedError, contTask.Exception, "Error enqueuing item to azure queue");
}
else
{
EnqueueOperationOperationRateLogger.Success();
}
},
TaskContinuationOptions.ExecuteSynchronously);
Counter.SetValue(CounterNames.AnalyticsAzureQueuePendingWrites, queue.PendingWrites);
// if too many pending writers. Start throtling
int wait = 0;
bool warningSent = false;
bool errorSent = false;
const int SleepTime = 100;
while (queue.PendingWrites > MaxPendingWriters)
{
wait++;
int totalSleepMilliseconds = wait * SleepTime;
// Send warning after 10 seconds of waiting
if (totalSleepMilliseconds > 10000 && !warningSent)
{
Log.Warn(
"The maximum # of pending async writes exceeds the maximum. Value={0}, waiting for {1} milliseconds",
queue.PendingWrites,
totalSleepMilliseconds);
warningSent = true;
}
// Send Error after the timeout of azure send operation passed
if (totalSleepMilliseconds >= AzureQueueWaitTimeout.TotalMilliseconds * 2 && !errorSent)
{
Log.Error(
"The maximum # of pending async writes exceeds the maximum. Value={0}, waiting for {1} milliseconds",
queue.PendingWrites,
totalSleepMilliseconds);
errorSent = true;
}
Thread.Sleep(SleepTime);
}
// clear batch
batch.Clear();
}
catch (Exception e)
{
Log.Error("Error in Analytics.Client.SaveBatch() " + e);
}
}