Example #1
0
        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;
        }