GrpcEnvironment.cs

#region Copyright notice and license

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//
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// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
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#endregion

using System;
using System.Runtime.InteropServices;
using System.Threading.Tasks;
using Grpc.Core.Internal;
using Grpc.Core.Logging;
using Grpc.Core.Utils;

namespace Grpc.Core
{
    /// <summary>
    /// Encapsulates initialization and shutdown of gRPC library.
    /// </summary>
    public class GrpcEnvironment
    {
        const int THREAD_POOL_SIZE = 4;

        [DllImport("grpc_csharp_ext.dll")]
        static extern void grpcsharp_init();

        [DllImport("grpc_csharp_ext.dll")]
        static extern void grpcsharp_shutdown();

        [DllImport("grpc_csharp_ext.dll")]
        static extern IntPtr grpcsharp_version_string();  // returns not-owned const char*

        static object staticLock = new object();
        static GrpcEnvironment instance;

        static ILogger logger = new ConsoleLogger();

        readonly GrpcThreadPool threadPool;
        readonly CompletionRegistry completionRegistry;
        readonly DebugStats debugStats = new DebugStats();
        bool isClosed;

        /// <summary>
        /// Returns an instance of initialized gRPC environment.
        /// Subsequent invocations return the same instance unless Shutdown has been called first.
        /// </summary>
        internal static GrpcEnvironment GetInstance()
        {
            lock (staticLock)
            {
                if (instance == null)
                {
                    instance = new GrpcEnvironment();
                }
                return instance;
            }
        }

        /// <summary>
        /// Shuts down the gRPC environment if it was initialized before.
        /// Blocks until the environment has been fully shutdown.
        /// </summary>
        public static void Shutdown()
        {
            lock (staticLock)
            {
                if (instance != null)
                {
                    instance.Close();
                    instance = null;
                }
            }
        }

        /// <summary>
        /// Gets application-wide logger used by gRPC.
        /// </summary>
        /// <value>The logger.</value>
        public static ILogger Logger
        {
            get
            {
                return logger;
            }
        }

        /// <summary>
        /// Sets the application-wide logger that should be used by gRPC.
        /// </summary>
        public static void SetLogger(ILogger customLogger)
        {
            Preconditions.CheckNotNull(customLogger, "customLogger");
            logger = customLogger;
        }

        /// <summary>
        /// Creates gRPC environment.
        /// </summary>
        private GrpcEnvironment()
        {
            NativeLogRedirector.Redirect();
            grpcsharp_init();
            completionRegistry = new CompletionRegistry(this);
            threadPool = new GrpcThreadPool(this, THREAD_POOL_SIZE);
            threadPool.Start();
            // TODO: use proper logging here
            Logger.Info("gRPC initialized.");
        }

        /// <summary>
        /// Gets the completion registry used by this gRPC environment.
        /// </summary>
        internal CompletionRegistry CompletionRegistry
        {
            get
            {
                return this.completionRegistry;
            }
        }

        /// <summary>
        /// Gets the completion queue used by this gRPC environment.
        /// </summary>
        internal CompletionQueueSafeHandle CompletionQueue
        {
            get
            {
                return this.threadPool.CompletionQueue;
            }
        }

        /// <summary>
        /// Gets the completion queue used by this gRPC environment.
        /// </summary>
        internal DebugStats DebugStats
        {
            get
            {
                return this.debugStats;
            }
        }

        /// <summary>
        /// Gets version of gRPC C core.
        /// </summary>
        internal static string GetCoreVersionString()
        {
            var ptr = grpcsharp_version_string();  // the pointer is not owned
            return Marshal.PtrToStringAnsi(ptr);
        }

        /// <summary>
        /// Shuts down this environment.
        /// </summary>
        private void Close()
        {
            if (isClosed)
            {
                throw new InvalidOperationException("Close has already been called");
            }
            threadPool.Stop();
            grpcsharp_shutdown();
            isClosed = true;

            debugStats.CheckOK();

            Logger.Info("gRPC shutdown.");
        }

        /// <summary>
        /// Shuts down this environment asynchronously.
        /// </summary>
        private Task CloseAsync()
        {
            return Task.Run(() =>
            {
                try
                {
                    Close();
                }
                catch (Exception e)
                {
                    Logger.Error(e, "Error occured while shutting down GrpcEnvironment.");
                }
            });
        }
    }
}