public async Task <IStreamMetadata> GetAsync(
StreamId streamId,
CancellationToken cancellationToken)
{
try
{
var metadata = await containerProvider
.GetStreamContainer()
.ReadItemAsync <StreamMetadata>(
StreamMetadata.StreamMetadataId,
new PartitionKey(streamId.Value),
cancellationToken: cancellationToken)
.ConfigureAwait(false);
metadata.Resource.ETag = metadata.ETag;
return(metadata.Resource);
}
catch (CosmosException ex)
when(ex.StatusCode == HttpStatusCode.NotFound)
{
return(new StreamMetadata(
StreamMetadata.StreamMetadataId,
streamId.Value,
streamId,
StreamVersion.StartOfStream,
StreamState.New,
timeProvider.GetDateTime()));
}
}
public IStreamSubscription Create(
ConsumerGroup consumerGroup,
SubscriptionStartOptions startOptions,
ProcessEventsHandler eventsHandler)
{
var builder = containerProvider
.GetStreamContainer()
.GetChangeFeedProcessorBuilder <EventDocument>(
GetProcessorName(consumerGroup),
(c, ct) => eventsHandler(c.Where(ExcludeMetaDataChanges).ToArray(), ct))
.WithLeaseContainer(containerProvider.GetSubscriptionContainer())
.WithMaxItems(100)
.WithPollInterval(TimeSpan.FromMilliseconds(1000));
if (startOptions == SubscriptionStartOptions.FromBegining)
{
// Instruct processor to start from beginning.
// see https://docs.microsoft.com/en-us/azure/cosmos-db/change-feed-processor#reading-from-the-beginning
builder.WithStartTime(DateTime.MinValue.ToUniversalTime());
}
if (!string.IsNullOrEmpty(consumerGroup.Instance))
{
builder.WithInstanceName(consumerGroup.Instance);
}
return(new CosmosSubscriptionProcessor(
telemetry,
builder.Build(),
consumerGroup));
}
public async Task <IStreamMetadata> WriteAsync(
StreamBatch batch,
CancellationToken cancellationToken)
{
var pk = new PartitionKey(batch.Metadata.StreamId.Value);
var tx = containerProvider
.GetStreamContainer()
.CreateTransactionalBatch(pk);
tx.UpsertItem(
batch.Metadata,
new TransactionalBatchItemRequestOptions {
IfMatchEtag = batch.Metadata.ETag
});
foreach (var document in batch.Documents)
{
tx.CreateItem(
document,
new TransactionalBatchItemRequestOptions {
EnableContentResponseOnWrite = false
});
}
if (IsEmptyStream(batch.Metadata))
{
await containerProvider
.GetIndexContainer()
.UpsertItemAsync(
new StreamIndex
{
StreamId = batch.Metadata.StreamId.Value,
Timestamp = dateTimeProvider.GetDateTime(),
IsActive = true,
},
new PartitionKey(nameof(StreamIndex)),
new ItemRequestOptions {
EnableContentResponseOnWrite = false
},
cancellationToken)
.ConfigureAwait(false);
}
using var batchResponse = await tx
.ExecuteAsync(cancellationToken)
.ConfigureAwait(false);
EnsureSuccess(batchResponse, batch.Metadata);
return(GetMetadataFromResponse(batchResponse));
}