IgniteAsyncStreamExtensions with System.Threading.Channels

IgniteAsyncStreamExtensions.cs

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Channels;
using Apache.Ignite.Core.Cache;
using Apache.Ignite.Core.Cache.Event;
using Apache.Ignite.Core.Cache.Query.Continuous;

namespace IgniteAsyncStreams
{
    public static class IgniteAsyncStreamExtensions
    {
        public static async IAsyncEnumerable<ICacheEntry<TK, TV>> QueryContinuousAsync<TK, TV>(
            this ICache<TK, TV> cache)
        {
            var queryListener = new AsyncContinuousQueryListener<TK, TV>();
            var continuousQuery = new ContinuousQuery<TK, TV>(queryListener);

            var handle = cache.QueryContinuous(continuousQuery);
            try
            {
                while (true)
                {
                    while (queryListener.Events.TryDequeue(out var entryEvent))
                    {
                        yield return entryEvent;
                    }

                    await queryListener.HasData.WaitAsync();
                }
            }
            finally
            {
                handle.Dispose();
                Console.WriteLine("Infinite loop exited");
            }
        }

        public static async IAsyncEnumerable<ICacheEntry<TK, TV>> QueryContinuousAsync2<TK, TV>(
            this ICache<TK, TV> cache)
        {
            var queryListener = new AsyncContinuousQueryChannelListener<TK, TV>();
            var continuousQuery = new ContinuousQuery<TK, TV>(queryListener);

            using (cache.QueryContinuous(continuousQuery))
            {
                while (true)
                {
                    yield return await queryListener.Reader.ReadAsync();
                }
            }
        }

        private class AsyncContinuousQueryListener<TK, TV> : ICacheEntryEventListener<TK, TV>
        {
            public readonly SemaphoreSlim HasData = new SemaphoreSlim(0, 1);

            public readonly ConcurrentQueue<ICacheEntryEvent<TK, TV>> Events
                = new ConcurrentQueue<ICacheEntryEvent<TK, TV>>();

            public void OnEvent(IEnumerable<ICacheEntryEvent<TK, TV>> events)
            {
                foreach (var entryEvent in events)
                {
                    Console.WriteLine("Received entry: " + entryEvent.Value);
                    Events.Enqueue(entryEvent);
                }

                HasData.Release();
            }
        }
    }

    public class AsyncContinuousQueryChannelListener<TK, TV> : ICacheEntryEventListener<TK, TV>
    {
        private readonly Channel<ICacheEntryEvent<TK, TV>> _channel =
            Channel.CreateUnbounded<ICacheEntryEvent<TK, TV>>();

        public ChannelReader<ICacheEntryEvent<TK, TV>> Reader => _channel.Reader;

        public void OnEvent(IEnumerable<ICacheEntryEvent<TK, TV>> evts)
        {
            foreach (var evt in evts)
            {
                var res = _channel.Writer.TryWrite(evt);
                if (!res)
                {
                    throw new Exception("Failed to write to channel");
                }
            }
        }
    }
}