HazelcastClientSingleton

HazelcastClientSingleton.cs

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

using System;
using System.Threading.Tasks;
using Hazelcast;
using Microsoft.Extensions.Options;

namespace WebApi31
{
    public class HazelcastClientSingleton : IDisposable
    {
        private readonly IOptions<HazelcastOptions> _options;
        private readonly object _mutex = new object();
        private ValueTask<IHazelcastClient> _starting;
        private bool _started;
        private IHazelcastClient _client;

        public HazelcastClientSingleton(IOptions<HazelcastOptions> options)
        {
            _options = options;
        }

        public ValueTask<IHazelcastClient> GetOrStartNewClientAsync()
        {
            lock (_mutex)
            {
                if (_client != null) return new ValueTask<IHazelcastClient>(_client);

                if (_started) return _starting;

                _starting = StartClientNewAsync();
                _started = true;
                return _starting;
            }
        }

        private async ValueTask<IHazelcastClient> StartClientNewAsync()
        {
            return _client = await HazelcastClientFactory.StartNewClientAsync(_options.Value);
        }

        public void Dispose()
        {
            // unfortunately the container which disposes the singleton does not do async
            _client?.DisposeAsync().GetAwaiter().GetResult();
        }
    }
}