private static async Task <(int, ChangeFeedCrossFeedRangeState)> PartialDrainAsync(IAsyncEnumerable <TryCatch <ChangeFeedPage> > asyncEnumerable)
{
ChangeFeedCrossFeedRangeState state = default;
int totalCount = 0;
await foreach (TryCatch <ChangeFeedPage> monadicPage in asyncEnumerable)
{
monadicPage.ThrowIfFailed();
ChangeFeedPage page = monadicPage.Result;
state = page.State;
if (page.NotModified)
{
break;
}
totalCount += page.Documents.Count;
}
return(totalCount, state);
}
public override async Task <ResponseMessage> ReadNextAsync(CancellationToken cancellationToken = default)
{
cancellationToken.ThrowIfCancellationRequested();
TryCatch <CrossPartitionChangeFeedAsyncEnumerator> monadicEnumerator = await this.lazyMonadicEnumerator.GetValueAsync(cancellationToken);
if (monadicEnumerator.Failed)
{
Exception createException = monadicEnumerator.Exception;
CosmosException cosmosException = ExceptionToCosmosException.CreateFromException(createException);
return(new ResponseMessage(
cosmosException.StatusCode,
requestMessage: null,
headers: cosmosException.Headers,
cosmosException: cosmosException,
diagnostics: new CosmosDiagnosticsContextCore()));
}
CrossPartitionChangeFeedAsyncEnumerator enumerator = monadicEnumerator.Result;
if (!await enumerator.MoveNextAsync())
{
throw new InvalidOperationException("ChangeFeed enumerator should always have a next continuation");
}
if (enumerator.Current.Failed)
{
CosmosException cosmosException = ExceptionToCosmosException.CreateFromException(enumerator.Current.Exception);
if (!IsRetriableException(cosmosException))
{
this.hasMoreResults = false;
}
return(new ResponseMessage(
cosmosException.StatusCode,
requestMessage: null,
headers: cosmosException.Headers,
cosmosException: cosmosException,
diagnostics: new CosmosDiagnosticsContextCore()));
}
ChangeFeedPage changeFeedPage = enumerator.Current.Result;
ResponseMessage responseMessage;
if (changeFeedPage is ChangeFeedSuccessPage changeFeedSuccessPage)
{
responseMessage = new ResponseMessage(statusCode: System.Net.HttpStatusCode.OK)
{
Content = changeFeedSuccessPage.Content
};
}
else
{
responseMessage = new ResponseMessage(statusCode: System.Net.HttpStatusCode.NotModified);
}
CosmosElement innerContinuationToken = ((ChangeFeedStateContinuation)changeFeedPage.State).ContinuationToken;
string continuationToken;
if (this.changeFeedRequestOptions.EmitOldContinuationToken)
{
List <ChangeFeedContinuationToken> parsedChangeFeedTokens = new List <ChangeFeedContinuationToken>();
CosmosArray changeFeedTokens = (CosmosArray)innerContinuationToken;
foreach (CosmosElement changeFeedToken in changeFeedTokens)
{
parsedChangeFeedTokens.Add(ChangeFeedContinuationToken.MonadicConvertFromCosmosElement(changeFeedToken).Result);
}
List <CompositeContinuationToken> compositeContinuationTokens = new List <CompositeContinuationToken>();
foreach (ChangeFeedContinuationToken changeFeedContinuationToken in parsedChangeFeedTokens)
{
string token = changeFeedContinuationToken.State is ChangeFeedStateContinuation changeFeedStateContinuation ? ((CosmosString)changeFeedStateContinuation.ContinuationToken).Value : null;
Documents.Routing.Range <string> range = ((FeedRangeEpk)changeFeedContinuationToken.Range).Range;
CompositeContinuationToken compositeContinuationToken = new CompositeContinuationToken()
{
Range = range,
Token = token,
};
compositeContinuationTokens.Add(compositeContinuationToken);
}
FeedRangeCompositeContinuation feedRangeCompositeContinuationToken = new FeedRangeCompositeContinuation(
await this.documentContainer.GetResourceIdentifierAsync(cancellationToken),
FeedRangeEpk.FullRange,
compositeContinuationTokens);
continuationToken = feedRangeCompositeContinuationToken.ToString();
}
else
{
continuationToken = VersionedAndRidCheckedCompositeToken.ToCosmosElement(
new VersionedAndRidCheckedCompositeToken(
VersionedAndRidCheckedCompositeToken.Version.V2,
innerContinuationToken,
await this.documentContainer.GetResourceIdentifierAsync(cancellationToken))).ToString();
}
responseMessage.Headers.ContinuationToken = continuationToken;
responseMessage.Headers.RequestCharge = changeFeedPage.RequestCharge;
responseMessage.Headers.ActivityId = changeFeedPage.ActivityId;
return(responseMessage);
}
