public async Task <long> Handle(GetMaximumSequenceNumberCommand request, CancellationToken cancellationToken)
{
var number = await _sequenceNumberRepository
.GetMaximumSequenceNumberAsync()
.ConfigureAwait(false);
return(number.Value);
}
public async Task <ICabinetReader?> GetNextUnacknowledgedAsync(ActorId recipient, params DomainOrigin[] domains)
{
ArgumentNullException.ThrowIfNull(recipient, nameof(recipient));
ArgumentNullException.ThrowIfNull(domains, nameof(domains));
if (domains.Length == 0)
{
domains = Enum.GetValues <DomainOrigin>();
}
var entryLookups = domains
.Where(domain => domain != DomainOrigin.Unknown)
.Select(domain =>
{
var asLinq = _repositoryContainer
.Catalog
.GetItemLinqQueryable <CosmosCatalogEntry>();
var partitionKey = string.Join('_', recipient.Value, domain);
var query =
from catalogEntry in asLinq
where catalogEntry.PartitionKey == partitionKey
orderby catalogEntry.NextSequenceNumber
select catalogEntry;
var task = query
.Take(1)
.AsCosmosIteratorAsync()
.FirstOrDefaultAsync();
return(new { domain, task });
});
var smallestDomain = DomainOrigin.Unknown;
CosmosCatalogEntry?smallestEntry = null;
foreach (var entryLookup in entryLookups.ToList())
{
var catalogEntry = await entryLookup.task.ConfigureAwait(false);
if (catalogEntry == null)
{
continue;
}
if (smallestEntry == null || smallestEntry.NextSequenceNumber > catalogEntry.NextSequenceNumber)
{
smallestEntry = catalogEntry;
smallestDomain = entryLookup.domain;
}
}
var maximumSequenceNumber = await _sequenceNumberRepository
.GetMaximumSequenceNumberAsync()
.ConfigureAwait(false);
if (smallestEntry == null || smallestEntry.NextSequenceNumber > maximumSequenceNumber.Value)
{
return(null);
}
var cabinetKey = new CabinetKey(
recipient,
smallestDomain,
new ContentType(smallestEntry.ContentType));
var cabinetReader = await GetCabinetReaderAsync(cabinetKey).ConfigureAwait(false);
if (cabinetReader.CanPeek)
{
var nextItem = cabinetReader.Peek();
if (nextItem.SequenceNumber.Value == smallestEntry.NextSequenceNumber)
{
return(cabinetReader);
}
}
// If SaveAsync fails to insert DataAvailable, for example due to crash/timeout,
// there will be a catalog entry pointing to a non-existent item.
await DeleteOldCatalogEntryAsync(smallestEntry).ConfigureAwait(false);
return(null);
}
