private async Task Process(Tracked <IStream> trackedStream)
{
var s = trackedStream.Value;
if (s.Version == ExpectedVersion.NoStream)
{
trackedStream.Complete();
return;
}
if (trackedStream.Completed.IsCompleted)
{
return;
}
var version = _versions.GetOrAdd(s.Key, ExpectedVersion.EmptyStream);
var origVersion = version;
// read from latest snapshot
var snapshotVersion = s.SnapshotVersion;
if (version < snapshotVersion && _projection.Latest > s.SnapshotTimestamp)
{
version = snapshotVersion - 1;
}
if (s.Version <= ExpectedVersion.EmptyStream)
{
s.Version = 0;
}
if (version > s.Version)
{
_log?.Warn($"Stream {s.Key} update is version {s.Version}, behind projection version {version}", GetDetailedName());
}
if (version < s.Version)
{
var t = await _eventStore.ReadStream <IEvent>(s, version + 1)
.TakeWhile(_ => !_token.IsCancellationRequested)
.Select(e => _projection.When(e))
.ToList()
.Timeout(Configuration.Timeout)
.LastOrDefaultAsync();
version += t.Count;
await Task.WhenAll(t);
_log?.Debug($"{s.Key}@{s.Version} <- {version}", $"{Parents.Select(p => p.Name).Aggregate((a, n) => a + n)}->{Name}");
if (!_versions.TryUpdate(s.Key, version, origVersion))
{
throw new InvalidOperationException("Failed updating concurrent versions of projections");
}
}
trackedStream.Complete();
}
