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);
FeedRangeState <ChangeFeedState> feedRangeState = new FeedRangeState <ChangeFeedState>(feedRangeEpk, state);
changeFeedTokensV2.Add(ChangeFeedFeedRangeStateSerializer.ToCosmosElement(feedRangeState));
}
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 <ChangeFeedCrossFeedRangeState> monadicChangeFeedCrossFeedRangeState = changeFeedStartFrom.Accept(ChangeFeedStateFromToChangeFeedCrossFeedRangeState.Singleton);
if (monadicChangeFeedCrossFeedRangeState.Failed)
{
return(TryCatch <CrossPartitionChangeFeedAsyncEnumerator> .FromException(
new MalformedChangeFeedContinuationTokenException(
message: $"Could not convert to {nameof(ChangeFeedCrossFeedRangeState)}.",
innerException: monadicChangeFeedCrossFeedRangeState.Exception)));
}
CrossPartitionChangeFeedAsyncEnumerator enumerator = CrossPartitionChangeFeedAsyncEnumerator.Create(
documentContainer,
changeFeedRequestOptions,
new CrossFeedRangeState <ChangeFeedState>(monadicChangeFeedCrossFeedRangeState.Result.FeedRangeStates),
cancellationToken: default);
TryCatch <CrossPartitionChangeFeedAsyncEnumerator> monadicEnumerator = TryCatch <CrossPartitionChangeFeedAsyncEnumerator> .FromResult(enumerator);
return(monadicEnumerator);
});
this.hasMoreResults = true;
}