public override TryCatch <CrossPartitionState <ChangeFeedState> > Visit(ChangeFeedStartFromContinuation startFromContinuation)
{
string continuationToken = startFromContinuation.Continuation;
TryCatch <CosmosArray> monadicCosmosArray = CosmosArray.Monadic.Parse(continuationToken);
if (monadicCosmosArray.Failed)
{
return(TryCatch <CrossPartitionState <ChangeFeedState> > .FromException(
new MalformedChangeFeedContinuationTokenException(
message : $"Array expected for change feed continuation token: {continuationToken}.",
innerException : monadicCosmosArray.Exception)));
}
CosmosArray cosmosArray = monadicCosmosArray.Result;
if (cosmosArray.Count == 0)
{
return(TryCatch <CrossPartitionState <ChangeFeedState> > .FromException(
new MalformedChangeFeedContinuationTokenException(
message : $"non empty array expected for change feed continuation token: {continuationToken}.")));
}
List <(FeedRangeInternal, ChangeFeedState)> rangeAndStates = new List <(FeedRangeInternal, ChangeFeedState)>();
foreach (CosmosElement arrayItem in cosmosArray)
{
TryCatch <ChangeFeedContinuationToken> monadicChangeFeedContinuationToken = ChangeFeedContinuationToken.MonadicConvertFromCosmosElement(arrayItem);
if (monadicChangeFeedContinuationToken.Failed)
{
return(TryCatch <CrossPartitionState <ChangeFeedState> > .FromException(
new MalformedChangeFeedContinuationTokenException(
message : $"Failed to parse change feed continuation token: {continuationToken}.",
innerException : monadicChangeFeedContinuationToken.Exception)));
}
ChangeFeedContinuationToken changeFeedContinuationToken = monadicChangeFeedContinuationToken.Result;
rangeAndStates.Add((changeFeedContinuationToken.Range, changeFeedContinuationToken.State));
}
CrossPartitionState <ChangeFeedState> crossPartitionState = new CrossPartitionState <ChangeFeedState>(rangeAndStates);
return(TryCatch <CrossPartitionState <ChangeFeedState> > .FromResult(crossPartitionState));
}
public ChangeFeedIteratorCore(
IDocumentContainer documentContainer,
ChangeFeedRequestOptions changeFeedRequestOptions,
ChangeFeedStartFrom changeFeedStartFrom)
{
if (changeFeedStartFrom == null)
{
throw new ArgumentNullException(nameof(changeFeedStartFrom));
}
this.documentContainer = documentContainer ?? throw new ArgumentNullException(nameof(documentContainer));
this.changeFeedRequestOptions = changeFeedRequestOptions ?? new ChangeFeedRequestOptions();
this.lazyMonadicEnumerator = new AsyncLazy <TryCatch <CrossPartitionChangeFeedAsyncEnumerator> >(
valueFactory: async(cancellationToken) =>
{
if (changeFeedStartFrom is ChangeFeedStartFromContinuation startFromContinuation)
{
TryCatch <CosmosElement> monadicParsedToken = CosmosElement.Monadic.Parse(startFromContinuation.Continuation);
if (monadicParsedToken.Failed)
{
return(TryCatch <CrossPartitionChangeFeedAsyncEnumerator> .FromException(
new MalformedChangeFeedContinuationTokenException(
message: $"Failed to parse continuation token: {startFromContinuation.Continuation}.",
innerException: monadicParsedToken.Exception)));
}
TryCatch <VersionedAndRidCheckedCompositeToken> monadicVersionedToken = VersionedAndRidCheckedCompositeToken
.MonadicCreateFromCosmosElement(monadicParsedToken.Result);
if (monadicVersionedToken.Failed)
{
return(TryCatch <CrossPartitionChangeFeedAsyncEnumerator> .FromException(
new MalformedChangeFeedContinuationTokenException(
message: $"Failed to parse continuation token: {startFromContinuation.Continuation}.",
innerException: monadicVersionedToken.Exception)));
}
VersionedAndRidCheckedCompositeToken versionedAndRidCheckedCompositeToken = monadicVersionedToken.Result;
if (versionedAndRidCheckedCompositeToken.VersionNumber == VersionedAndRidCheckedCompositeToken.Version.V1)
{
// Need to migrate continuation token
if (!(versionedAndRidCheckedCompositeToken.ContinuationToken is CosmosArray cosmosArray))
{
return(TryCatch <CrossPartitionChangeFeedAsyncEnumerator> .FromException(
new MalformedChangeFeedContinuationTokenException(
message: $"Failed to parse get array continuation token: {startFromContinuation.Continuation}.")));
}
List <CosmosElement> changeFeedTokensV2 = new List <CosmosElement>();
foreach (CosmosElement arrayItem in cosmosArray)
{
if (!(arrayItem is CosmosObject cosmosObject))
{
return(TryCatch <CrossPartitionChangeFeedAsyncEnumerator> .FromException(
new MalformedChangeFeedContinuationTokenException(
message: $"Failed to parse get object in composite continuation: {startFromContinuation.Continuation}.")));
}
if (!cosmosObject.TryGetValue("min", out CosmosString min))
{
return(TryCatch <CrossPartitionChangeFeedAsyncEnumerator> .FromException(
new MalformedChangeFeedContinuationTokenException(
message: $"Failed to parse start of range: {cosmosObject}.")));
}
if (!cosmosObject.TryGetValue("max", out CosmosString max))
{
return(TryCatch <CrossPartitionChangeFeedAsyncEnumerator> .FromException(
new MalformedChangeFeedContinuationTokenException(
message: $"Failed to parse end of range: {cosmosObject}.")));
}
if (!cosmosObject.TryGetValue("token", out CosmosElement token))
{
return(TryCatch <CrossPartitionChangeFeedAsyncEnumerator> .FromException(
new MalformedChangeFeedContinuationTokenException(
message: $"Failed to parse token: {cosmosObject}.")));
}
FeedRangeEpk feedRangeEpk = new FeedRangeEpk(new Documents.Routing.Range <string>(
min: min.Value,
max: max.Value,
isMinInclusive: true,
isMaxInclusive: false));
ChangeFeedState state = token is CosmosNull ? ChangeFeedState.Beginning() : ChangeFeedStateContinuation.Continuation(token);
ChangeFeedContinuationToken changeFeedContinuationToken = new ChangeFeedContinuationToken(feedRangeEpk, state);
changeFeedTokensV2.Add(ChangeFeedContinuationToken.ToCosmosElement(changeFeedContinuationToken));
}
CosmosArray changeFeedTokensArrayV2 = CosmosArray.Create(changeFeedTokensV2);
versionedAndRidCheckedCompositeToken = new VersionedAndRidCheckedCompositeToken(
VersionedAndRidCheckedCompositeToken.Version.V2,
changeFeedTokensArrayV2,
versionedAndRidCheckedCompositeToken.Rid);
}
if (versionedAndRidCheckedCompositeToken.VersionNumber != VersionedAndRidCheckedCompositeToken.Version.V2)
{
return(TryCatch <CrossPartitionChangeFeedAsyncEnumerator> .FromException(
new MalformedChangeFeedContinuationTokenException(
message: $"Wrong version number: {versionedAndRidCheckedCompositeToken.VersionNumber}.")));
}
string collectionRid = await documentContainer.GetResourceIdentifierAsync(cancellationToken);
if (versionedAndRidCheckedCompositeToken.Rid != collectionRid)
{
return(TryCatch <CrossPartitionChangeFeedAsyncEnumerator> .FromException(
new MalformedChangeFeedContinuationTokenException(
message: $"rids mismatched. Expected: {collectionRid} but got {versionedAndRidCheckedCompositeToken.Rid}.")));
}
changeFeedStartFrom = ChangeFeedStartFrom.ContinuationToken(versionedAndRidCheckedCompositeToken.ContinuationToken.ToString());
}
TryCatch <CrossPartitionChangeFeedAsyncEnumerator> monadicEnumerator = CrossPartitionChangeFeedAsyncEnumerator.MonadicCreate(
documentContainer,
changeFeedRequestOptions,
changeFeedStartFrom,
cancellationToken: default);
return(monadicEnumerator);
});
this.hasMoreResults = true;
}
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);
}
