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; }