private async void WaitForReplicationFromServerAsync(string url, AsyncCountdownEvent countDown, Etag etag, BlockingCollection<Exception> errors)
{
try
{
while (countDown.Active)
{
var etags = await GetReplicatedEtagsFor(url);
var replicated = etag.CompareTo(etags.DocumentEtag) <= 0 || etag.CompareTo(etags.AttachmentEtag) <= 0;
if (!replicated)
{
if (countDown.Active)
{
#if NET45
await Task.Delay(100);
#else
await TaskEx.Delay(100);
#endif
}
continue;
}
countDown.Signal();
return;
}
}
catch (Exception ex)
{
errors.Add(ex);
countDown.Signal();
}
}
/// <summary>
/// Represents an replication operation to all destination servers of an item specified by ETag
/// </summary>
/// <param name="etag">ETag of an replicated item</param>
/// <param name="timeout">Optional timeout</param>
/// <param name="database">The database from which to check, if null, the default database for the document store connection string</param>
/// <param name="replicas">The min number of replicas that must have the value before we can return (or the number of destinations, if higher)</param>
/// <returns>Task which will have the number of nodes that the caught up to the specified etag</returns>
public async Task<int> WaitAsync(Etag etag = null, TimeSpan? timeout = null, string database = null, int replicas = 2)
{
etag = etag ?? documentStore.LastEtagHolder.GetLastWrittenEtag();
if (etag == Etag.Empty)
return replicas; // if the etag is empty, nothing to do
var asyncDatabaseCommands = documentStore.AsyncDatabaseCommands;
if (database != null)
asyncDatabaseCommands = asyncDatabaseCommands.ForDatabase(database);
asyncDatabaseCommands.ForceReadFromMaster();
var doc = await asyncDatabaseCommands.GetAsync("Raven/Replication/Destinations");
if (doc == null)
return -1;
var replicationDocument = doc.DataAsJson.JsonDeserialization<ReplicationDocument>();
if (replicationDocument == null)
return -1;
var destinationsToCheck = replicationDocument.Destinations
.Where(
x => x.Disabled == false && x.IgnoredClient == false)
.Select(x => x.ClientVisibleUrl ?? x.Url)
.ToList();
if (destinationsToCheck.Count == 0)
return 0;
int toCheck = Math.Min(replicas, destinationsToCheck.Count);
var countDown = new AsyncCountdownEvent(toCheck);
var errors = new BlockingCollection<Exception>();
foreach (var url in destinationsToCheck)
{
WaitForReplicationFromServerAsync(url, countDown, etag, errors);
}
if (await countDown.WaitAsync().WaitWithTimeout(timeout) == false)
{
throw new TimeoutException(
string.Format("Confirmed that the specified etag {0} was replicated to {1} of {2} servers, during {3}", etag,
(toCheck - countDown.Count),
toCheck,
timeout));
}
if (errors.Count > 0 && countDown.Count > 0)
throw new AggregateException(errors);
return countDown.Count;
}
