public KafkaBackedDb(IChangeTrackingDataStore dataStore, KafkaConsumer <TValue> kafkaConsumer)
{
_dataStore = dataStore;
_dataStore.GetChanges <Offset>().Subscribe(offset => Console.WriteLine(offset));
var offsetKey = $"{typeof(TValue).Name}.offset";
var currentOffset = _dataStore.Get <long>(offsetKey).Result;
kafkaConsumer.SeekToOffset(currentOffset);
kafkaConsumer.Start();
kafkaConsumer.Subscription
.ObserveOn(TaskPoolScheduler.Default)
.SubscribeOn(TaskPoolScheduler.Default)
.Subscribe(async message =>
{
var value = message.Value;
var currentValue = await _dataStore.Get <TValue>(message.Key);
if (!(currentValue is null))
{
value.UpdateObject(currentValue);
}
await _dataStore.Set(value, message.Key);
await _dataStore.Set(message.Offset.Value, offsetKey);
});
}
public IObservable <TValue> GetChanges() => _dataStore.GetChanges <TValue>();
public IObservable <T> GetChanges <T>() => _fast.GetChanges <T>().Merge(_slow.GetChanges <T>()).Distinct();