no need to call GrpcEnvironment.Initialize() explicitly

src/csharp/Grpc.Core.Tests/ClientServerTest.cs

@@ -73,12 +73,6 @@ namespace Grpc.Core.Tests
         Server server;
         Channel channel;
 
-        [TestFixtureSetUp]
-        public void InitClass()
-        {
-            GrpcEnvironment.Initialize();
-        }
-
         [SetUp]
         public void Init()
         {

src/csharp/Grpc.Core.Tests/GrpcEnvironmentTest.cs

@@ -43,16 +43,17 @@ namespace Grpc.Core.Tests
         [Test]
         public void InitializeAndShutdownGrpcEnvironment()
         {
-            GrpcEnvironment.Initialize();
-            Assert.IsNotNull(GrpcEnvironment.ThreadPool.CompletionQueue);
+            var env = GrpcEnvironment.GetInstance();
+            Assert.IsNotNull(env.CompletionQueue);
             GrpcEnvironment.Shutdown();
         }
 
         [Test]
         public void SubsequentInvocations()
         {
-            GrpcEnvironment.Initialize();
-            GrpcEnvironment.Initialize();
+            var env1 = GrpcEnvironment.GetInstance();
+            var env2 = GrpcEnvironment.GetInstance();
+            Assert.IsTrue(object.ReferenceEquals(env1, env2));
             GrpcEnvironment.Shutdown();
             GrpcEnvironment.Shutdown();
         }
@@ -60,15 +61,13 @@ namespace Grpc.Core.Tests
         [Test]
         public void InitializeAfterShutdown()
         {
-            GrpcEnvironment.Initialize();
-            var tp1 = GrpcEnvironment.ThreadPool;
+            var env1 = GrpcEnvironment.GetInstance();
             GrpcEnvironment.Shutdown();
 
-            GrpcEnvironment.Initialize();
-            var tp2 = GrpcEnvironment.ThreadPool;
+            var env2 = GrpcEnvironment.GetInstance();
             GrpcEnvironment.Shutdown();
 
-            Assert.IsFalse(object.ReferenceEquals(tp1, tp2));
+            Assert.IsFalse(object.ReferenceEquals(env1, env2));
         }
     }
 }

src/csharp/Grpc.Core.Tests/PInvokeTest.cs

@@ -53,18 +53,6 @@ namespace Grpc.Core.Tests
         [DllImport("grpc_csharp_ext.dll")]
         static extern IntPtr grpcsharp_test_nop(IntPtr ptr);
 
-        [TestFixtureSetUp]
-        public void Init()
-        {
-            GrpcEnvironment.Initialize();
-        }
-
-        [TestFixtureTearDown]
-        public void Cleanup()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         /// <summary>
         /// (~1.26us .NET Windows)
         /// </summary>

src/csharp/Grpc.Core.Tests/ServerTest.cs

@@ -44,13 +44,10 @@ namespace Grpc.Core.Tests
         [Test]
         public void StartAndShutdownServer()
         {
-            GrpcEnvironment.Initialize();
-
             Server server = new Server();
             server.AddListeningPort("localhost", Server.PickUnusedPort);
             server.Start();
             server.ShutdownAsync().Wait();
-
             GrpcEnvironment.Shutdown();
         }
     }

src/csharp/Grpc.Core/Calls.cs

@@ -58,7 +58,7 @@ namespace Grpc.Core
             where TResponse : class
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
-            asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
+            asyncCall.Initialize(call.Channel, call.Channel.CompletionQueue, call.Name);
             var asyncResult = asyncCall.UnaryCallAsync(req, call.Headers);
             RegisterCancellationCallback(asyncCall, token);
             return await asyncResult;
@@ -69,7 +69,7 @@ namespace Grpc.Core
             where TResponse : class
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
-            asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
+            asyncCall.Initialize(call.Channel, call.Channel.CompletionQueue, call.Name);
             asyncCall.StartServerStreamingCall(req, call.Headers);
             RegisterCancellationCallback(asyncCall, token);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
@@ -81,7 +81,7 @@ namespace Grpc.Core
             where TResponse : class
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
-            asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
+            asyncCall.Initialize(call.Channel, call.Channel.CompletionQueue, call.Name);
             var resultTask = asyncCall.ClientStreamingCallAsync(call.Headers);
             RegisterCancellationCallback(asyncCall, token);
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
@@ -93,7 +93,7 @@ namespace Grpc.Core
             where TResponse : class
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call.RequestMarshaller.Serializer, call.ResponseMarshaller.Deserializer);
-            asyncCall.Initialize(call.Channel, GetCompletionQueue(), call.Name);
+            asyncCall.Initialize(call.Channel, call.Channel.CompletionQueue, call.Name);
             asyncCall.StartDuplexStreamingCall(call.Headers);
             RegisterCancellationCallback(asyncCall, token);
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
@@ -108,13 +108,5 @@ namespace Grpc.Core
                 token.Register(() => asyncCall.Cancel());
             }
         }
-
-        /// <summary>
-        /// Gets shared completion queue used for async calls.
-        /// </summary>
-        private static CompletionQueueSafeHandle GetCompletionQueue()
-        {
-            return GrpcEnvironment.ThreadPool.CompletionQueue;
-        }
     }
 }

src/csharp/Grpc.Core/Channel.cs

@@ -42,8 +42,10 @@ namespace Grpc.Core
     /// </summary>
     public class Channel : IDisposable
     {
+        readonly GrpcEnvironment environment;
         readonly ChannelSafeHandle handle;
         readonly string target;
+        bool disposed;
 
         /// <summary>
         /// Creates a channel that connects to a specific host.
@@ -54,6 +56,7 @@ namespace Grpc.Core
         /// <param name="options">Channel options.</param>
         public Channel(string host, Credentials credentials = null, IEnumerable<ChannelOption> options = null)
         {
+            this.environment = GrpcEnvironment.GetInstance();
             using (ChannelArgsSafeHandle nativeChannelArgs = ChannelOptions.CreateChannelArgs(options))
             {
                 if (credentials != null)
@@ -105,10 +108,35 @@ namespace Grpc.Core
             }
         }
 
+        internal CompletionQueueSafeHandle CompletionQueue
+        {
+            get
+            {
+                return this.environment.CompletionQueue;
+            }
+        }
+
+        internal CompletionRegistry CompletionRegistry
+        {
+            get
+            {
+                return this.environment.CompletionRegistry;
+            }
+        }
+
+        internal GrpcEnvironment Environment
+        {
+            get
+            {
+                return this.environment;
+            }
+        }
+
         protected virtual void Dispose(bool disposing)
         {
-            if (handle != null && !handle.IsInvalid)
+            if (disposing && handle != null && !disposed)
             {
+                disposed = true;
                 handle.Dispose();
             }
         }

src/csharp/Grpc.Core/GrpcEnvironment.cs

@@ -33,7 +33,9 @@
 
 using System;
 using System.Runtime.InteropServices;
+using System.Threading.Tasks;
 using Grpc.Core.Internal;
+using Grpc.Core.Utils;
 
 namespace Grpc.Core
 {
@@ -51,20 +53,18 @@ namespace Grpc.Core
         static extern void grpcsharp_shutdown();
 
         static object staticLock = new object();
-        static volatile GrpcEnvironment instance;
+        static GrpcEnvironment instance;
 
         readonly GrpcThreadPool threadPool;
         readonly CompletionRegistry completionRegistry;
+        readonly DebugStats debugStats = new DebugStats();
         bool isClosed;
 
         /// <summary>
-        /// Makes sure GRPC environment is initialized. Subsequent invocations don't have any
-        /// effect unless you call Shutdown first.
-        /// Although normal use cases assume you will call this just once in your application's
-        /// lifetime (and call Shutdown once you're done), for the sake of easier testing it's
-        /// allowed to initialize the environment again after it has been successfully shutdown.
+        /// Returns an instance of initialized gRPC environment.
+        /// Subsequent invocations return the same instance unless Shutdown has been called first.
         /// </summary>
-        public static void Initialize()
+        internal static GrpcEnvironment GetInstance()
         {
             lock (staticLock)
             {
@@ -72,12 +72,13 @@ namespace Grpc.Core
                 {
                     instance = new GrpcEnvironment();
                 }
+                return instance;
             }
         }
 
         /// <summary>
-        /// Shuts down the GRPC environment if it was initialized before.
-        /// Repeated invocations have no effect.
+        /// Shuts down the gRPC environment if it was initialized before.
+        /// Blocks until the environment has been fully shutdown.
         /// </summary>
         public static void Shutdown()
         {
@@ -87,50 +88,55 @@ namespace Grpc.Core
                 {
                     instance.Close();
                     instance = null;
-
-                    CheckDebugStats();
                 }
             }
         }
 
-        internal static GrpcThreadPool ThreadPool
+        /// <summary>
+        /// Creates gRPC environment.
+        /// </summary>
+        private GrpcEnvironment()
         {
-            get
+            GrpcLog.RedirectNativeLogs(Console.Error);
+            grpcsharp_init();
+            completionRegistry = new CompletionRegistry(this);
+            threadPool = new GrpcThreadPool(this, THREAD_POOL_SIZE);
+            threadPool.Start();
+            // TODO: use proper logging here
+            Console.WriteLine("GRPC initialized.");
+        }
+
+        /// <summary>
+        /// Gets the completion registry used by this gRPC environment.
+        /// </summary>
+        internal CompletionRegistry CompletionRegistry
         {
-                var inst = instance;
-                if (inst == null)
+            get
             {
-                    throw new InvalidOperationException("GRPC environment not initialized");
-                }
-                return inst.threadPool;
+                return this.completionRegistry;
             }
         }
 
-        internal static CompletionRegistry CompletionRegistry
+        /// <summary>
+        /// Gets the completion queue used by this gRPC environment.
+        /// </summary>
+        internal CompletionQueueSafeHandle CompletionQueue
         {
             get
             {
-                var inst = instance;
-                if (inst == null)
-                {
-                    throw new InvalidOperationException("GRPC environment not initialized");
-                }
-                return inst.completionRegistry;
+                return this.threadPool.CompletionQueue;
             }
         }
 
         /// <summary>
-        /// Creates gRPC environment.
+        /// Gets the completion queue used by this gRPC environment.
         /// </summary>
-        private GrpcEnvironment()
+        internal DebugStats DebugStats
         {
-            GrpcLog.RedirectNativeLogs(Console.Error);
-            grpcsharp_init();
-            completionRegistry = new CompletionRegistry();
-            threadPool = new GrpcThreadPool(THREAD_POOL_SIZE);
-            threadPool.Start();
-            // TODO: use proper logging here
-            Console.WriteLine("GRPC initialized.");
+            get
+            {
+                return this.debugStats;
+            }
         }
 
         /// <summary>
@@ -146,32 +152,28 @@ namespace Grpc.Core
             grpcsharp_shutdown();
             isClosed = true;
 
+            debugStats.CheckOK();
+
             // TODO: use proper logging here
             Console.WriteLine("GRPC shutdown.");
         }
 
-        private static void CheckDebugStats()
+        /// <summary>
+        /// Shuts down this environment asynchronously.
+        /// </summary>
+        private Task CloseAsync()
         {
-            var remainingClientCalls = DebugStats.ActiveClientCalls.Count;
-            if (remainingClientCalls != 0)
+            return Task.Run(() =>
             {
-                DebugWarning(string.Format("Detected {0} client calls that weren't disposed properly.", remainingClientCalls));
-            }
-            var remainingServerCalls = DebugStats.ActiveServerCalls.Count;
-            if (remainingServerCalls != 0)
+                try
                 {
-                DebugWarning(string.Format("Detected {0} server calls that weren't disposed properly.", remainingServerCalls));
+                    Close();
                 }
-            var pendingBatchCompletions = DebugStats.PendingBatchCompletions.Count;
-            if (pendingBatchCompletions != 0)
+                catch (Exception e)
                 {
-                DebugWarning(string.Format("Detected {0} pending batch completions.", pendingBatchCompletions));
-            }
+                    Console.WriteLine("Error occured while shutting down GrpcEnvironment: " + e);
                 }
-
-        private static void DebugWarning(string message)
-        {
-            throw new Exception("Shutdown check: " + message);
+            });
         }
     }
 }

src/csharp/Grpc.Core/Internal/AsyncCall.cs

@@ -47,6 +47,8 @@ namespace Grpc.Core.Internal
     /// </summary>
     internal class AsyncCall<TRequest, TResponse> : AsyncCallBase<TRequest, TResponse>
     {
+        Channel channel;
+
         // Completion of a pending unary response if not null.
         TaskCompletionSource<TResponse> unaryResponseTcs;
 
@@ -61,8 +63,9 @@ namespace Grpc.Core.Internal
 
         public void Initialize(Channel channel, CompletionQueueSafeHandle cq, string methodName)
         {
-            var call = CallSafeHandle.Create(channel.Handle, cq, methodName, channel.Target, Timespec.InfFuture);
-            DebugStats.ActiveClientCalls.Increment();
+            this.channel = channel;
+            var call = CallSafeHandle.Create(channel.Handle, channel.CompletionRegistry, cq, methodName, channel.Target, Timespec.InfFuture);
+            channel.Environment.DebugStats.ActiveClientCalls.Increment();
             InitializeInternal(call);
         }
 
@@ -277,7 +280,7 @@ namespace Grpc.Core.Internal
 
         protected override void OnReleaseResources()
         {
-            DebugStats.ActiveClientCalls.Decrement();
+            channel.Environment.DebugStats.ActiveClientCalls.Decrement();
         }
 
         /// <summary>

src/csharp/Grpc.Core/Internal/AsyncCallServer.cs

@@ -48,14 +48,17 @@ namespace Grpc.Core.Internal
     internal class AsyncCallServer<TRequest, TResponse> : AsyncCallBase<TResponse, TRequest>
     {
         readonly TaskCompletionSource<object> finishedServersideTcs = new TaskCompletionSource<object>();
+        readonly GrpcEnvironment environment;
 
-        public AsyncCallServer(Func<TResponse, byte[]> serializer, Func<byte[], TRequest> deserializer) : base(serializer, deserializer)
+        public AsyncCallServer(Func<TResponse, byte[]> serializer, Func<byte[], TRequest> deserializer, GrpcEnvironment environment) : base(serializer, deserializer)
         {
+            this.environment = Preconditions.CheckNotNull(environment);
         }
 
         public void Initialize(CallSafeHandle call)
         {
-            DebugStats.ActiveServerCalls.Increment();
+            call.SetCompletionRegistry(environment.CompletionRegistry);
+            environment.DebugStats.ActiveServerCalls.Increment();
             InitializeInternal(call);
         }
 
@@ -114,7 +117,7 @@ namespace Grpc.Core.Internal
 
         protected override void OnReleaseResources()
         {
-            DebugStats.ActiveServerCalls.Decrement();
+            environment.DebugStats.ActiveServerCalls.Decrement();
         }
 
         /// <summary>

src/csharp/Grpc.Core/Internal/CallSafeHandle.cs

@@ -43,6 +43,7 @@ namespace Grpc.Core.Internal
     internal class CallSafeHandle : SafeHandleZeroIsInvalid
     {
         const uint GRPC_WRITE_BUFFER_HINT = 1;
+        CompletionRegistry completionRegistry;
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern CallSafeHandle grpcsharp_channel_create_call(ChannelSafeHandle channel, CompletionQueueSafeHandle cq, string method, string host, Timespec deadline);
@@ -97,15 +98,22 @@ namespace Grpc.Core.Internal
         {
         }
 
-        public static CallSafeHandle Create(ChannelSafeHandle channel, CompletionQueueSafeHandle cq, string method, string host, Timespec deadline)
+        public static CallSafeHandle Create(ChannelSafeHandle channel, CompletionRegistry registry, CompletionQueueSafeHandle cq, string method, string host, Timespec deadline)
         {
-            return grpcsharp_channel_create_call(channel, cq, method, host, deadline);
+            var result = grpcsharp_channel_create_call(channel, cq, method, host, deadline);
+            result.SetCompletionRegistry(registry);
+            return result;
+        }
+
+        public void SetCompletionRegistry(CompletionRegistry completionRegistry)
+        {
+            this.completionRegistry = completionRegistry;
         }
 
         public void StartUnary(byte[] payload, BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, callback);
             grpcsharp_call_start_unary(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray)
                 .CheckOk();
         }
@@ -119,56 +127,56 @@ namespace Grpc.Core.Internal
         public void StartClientStreaming(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, callback);
             grpcsharp_call_start_client_streaming(this, ctx, metadataArray).CheckOk();
         }
 
         public void StartServerStreaming(byte[] payload, BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, callback);
             grpcsharp_call_start_server_streaming(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray).CheckOk();
         }
 
         public void StartDuplexStreaming(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, callback);
             grpcsharp_call_start_duplex_streaming(this, ctx, metadataArray).CheckOk();
         }
 
         public void StartSendMessage(byte[] payload, BatchCompletionDelegate callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, callback);
             grpcsharp_call_send_message(this, ctx, payload, new UIntPtr((ulong)payload.Length)).CheckOk();
         }
 
         public void StartSendCloseFromClient(BatchCompletionDelegate callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, callback);
             grpcsharp_call_send_close_from_client(this, ctx).CheckOk();
         }
 
         public void StartSendStatusFromServer(Status status, BatchCompletionDelegate callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, callback);
             grpcsharp_call_send_status_from_server(this, ctx, status.StatusCode, status.Detail).CheckOk();
         }
 
         public void StartReceiveMessage(BatchCompletionDelegate callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, callback);
             grpcsharp_call_recv_message(this, ctx).CheckOk();
         }
 
         public void StartServerSide(BatchCompletionDelegate callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, callback);
             grpcsharp_call_start_serverside(this, ctx).CheckOk();
         }
 

src/csharp/Grpc.Core/Internal/CompletionRegistry.cs

@@ -45,11 +45,17 @@ namespace Grpc.Core.Internal
 
     internal class CompletionRegistry
     {
+        readonly GrpcEnvironment environment;
         readonly ConcurrentDictionary<IntPtr, OpCompletionDelegate> dict = new ConcurrentDictionary<IntPtr, OpCompletionDelegate>();
 
+        public CompletionRegistry(GrpcEnvironment environment)
+        {
+            this.environment = environment;
+        }
+
         public void Register(IntPtr key, OpCompletionDelegate callback)
         {
-            DebugStats.PendingBatchCompletions.Increment();
+            environment.DebugStats.PendingBatchCompletions.Increment();
             Preconditions.CheckState(dict.TryAdd(key, callback));
         }
 
@@ -63,7 +69,7 @@ namespace Grpc.Core.Internal
         {
             OpCompletionDelegate value;
             Preconditions.CheckState(dict.TryRemove(key, out value));
-            DebugStats.PendingBatchCompletions.Decrement();
+            environment.DebugStats.PendingBatchCompletions.Decrement();
             return value;
         }
 

src/csharp/Grpc.Core/Internal/DebugStats.cs

@@ -36,12 +36,39 @@ using System.Threading;
 
 namespace Grpc.Core.Internal
 {
-    internal static class DebugStats
+    internal class DebugStats
     {
-        public static readonly AtomicCounter ActiveClientCalls = new AtomicCounter();
+        public readonly AtomicCounter ActiveClientCalls = new AtomicCounter();
 
-        public static readonly AtomicCounter ActiveServerCalls = new AtomicCounter();
+        public readonly AtomicCounter ActiveServerCalls = new AtomicCounter();
 
-        public static readonly AtomicCounter PendingBatchCompletions = new AtomicCounter();
+        public readonly AtomicCounter PendingBatchCompletions = new AtomicCounter();
+
+        /// <summary>
+        /// Checks the debug stats and take action for any inconsistency found.
+        /// </summary>
+        public void CheckOK()
+        {
+            var remainingClientCalls = ActiveClientCalls.Count;
+            if (remainingClientCalls != 0)
+            {                
+                DebugWarning(string.Format("Detected {0} client calls that weren't disposed properly.", remainingClientCalls));
+            }
+            var remainingServerCalls = ActiveServerCalls.Count;
+            if (remainingServerCalls != 0)
+            {
+                DebugWarning(string.Format("Detected {0} server calls that weren't disposed properly.", remainingServerCalls));
+            }
+            var pendingBatchCompletions = PendingBatchCompletions.Count;
+            if (pendingBatchCompletions != 0)
+            {
+                DebugWarning(string.Format("Detected {0} pending batch completions.", pendingBatchCompletions));
+            }
+        }
+
+        private void DebugWarning(string message)
+        {
+            throw new Exception("Shutdown check: " + message);
+        }
     }
 }

src/csharp/Grpc.Core/Internal/GrpcThreadPool.cs

@@ -45,14 +45,16 @@ namespace Grpc.Core.Internal
     /// </summary>
     internal class GrpcThreadPool
     {
+        readonly GrpcEnvironment environment;
         readonly object myLock = new object();
         readonly List<Thread> threads = new List<Thread>();
         readonly int poolSize;
 
         CompletionQueueSafeHandle cq;
 
-        public GrpcThreadPool(int poolSize)
+        public GrpcThreadPool(GrpcEnvironment environment, int poolSize)
         {
+            this.environment = environment;
             this.poolSize = poolSize;
         }
 
@@ -80,7 +82,7 @@ namespace Grpc.Core.Internal
             {
                 cq.Shutdown();
 
-                Console.WriteLine("Waiting for GPRC threads to finish.");
+                Console.WriteLine("Waiting for GRPC threads to finish.");
                 foreach (var thread in threads)
                 {
                     thread.Join();
@@ -122,7 +124,7 @@ namespace Grpc.Core.Internal
                     IntPtr tag = ev.tag;
                     try
                     {
-                        var callback = GrpcEnvironment.CompletionRegistry.Extract(tag);
+                        var callback = environment.CompletionRegistry.Extract(tag);
                         callback(success);
                     }
                     catch (Exception e)

src/csharp/Grpc.Core/Internal/ServerCallHandler.cs

@@ -42,7 +42,7 @@ namespace Grpc.Core.Internal
 {
     internal interface IServerCallHandler
     {
-        Task HandleCall(string methodName, CallSafeHandle call, CompletionQueueSafeHandle cq);
+        Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment);
     }
 
     internal class UnaryServerCallHandler<TRequest, TResponse> : IServerCallHandler
@@ -58,11 +58,12 @@ namespace Grpc.Core.Internal
             this.handler = handler;
         }
 
-        public async Task HandleCall(string methodName, CallSafeHandle call, CompletionQueueSafeHandle cq)
+        public async Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment)
         {
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
-                method.RequestMarshaller.Deserializer);
+                method.RequestMarshaller.Deserializer,
+                environment);
 
             asyncCall.Initialize(call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -110,11 +111,12 @@ namespace Grpc.Core.Internal
             this.handler = handler;
         }
 
-        public async Task HandleCall(string methodName, CallSafeHandle call, CompletionQueueSafeHandle cq)
+        public async Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment)
         {
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
-                method.RequestMarshaller.Deserializer);
+                method.RequestMarshaller.Deserializer,
+                environment);
 
             asyncCall.Initialize(call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -163,11 +165,12 @@ namespace Grpc.Core.Internal
             this.handler = handler;
         }
 
-        public async Task HandleCall(string methodName, CallSafeHandle call, CompletionQueueSafeHandle cq)
+        public async Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment)
         {
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
-                method.RequestMarshaller.Deserializer);
+                method.RequestMarshaller.Deserializer,
+                environment);
 
             asyncCall.Initialize(call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -219,11 +222,12 @@ namespace Grpc.Core.Internal
             this.handler = handler;
         }
 
-        public async Task HandleCall(string methodName, CallSafeHandle call, CompletionQueueSafeHandle cq)
+        public async Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment)
         {
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
-                method.RequestMarshaller.Deserializer);
+                method.RequestMarshaller.Deserializer,
+                environment);
 
             asyncCall.Initialize(call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -255,11 +259,11 @@ namespace Grpc.Core.Internal
 
     internal class NoSuchMethodCallHandler : IServerCallHandler
     {
-        public async Task HandleCall(string methodName, CallSafeHandle call, CompletionQueueSafeHandle cq)
+        public async Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment)
         {
             // We don't care about the payload type here.
             var asyncCall = new AsyncCallServer<byte[], byte[]>(
-                (payload) => payload, (payload) => payload);
+                (payload) => payload, (payload) => payload, environment);
             
             asyncCall.Initialize(call);
             var finishedTask = asyncCall.ServerSideCallAsync();

src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs

@@ -92,18 +92,18 @@ namespace Grpc.Core.Internal
             grpcsharp_server_start(this);
         }
     
-        public void ShutdownAndNotify(CompletionQueueSafeHandle cq, BatchCompletionDelegate callback)
+        public void ShutdownAndNotify(BatchCompletionDelegate callback, GrpcEnvironment environment)
         {
             var ctx = BatchContextSafeHandle.Create();
-            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
-            grpcsharp_server_shutdown_and_notify_callback(this, cq, ctx);
+            environment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_server_shutdown_and_notify_callback(this, environment.CompletionQueue, ctx);
         }
 
-        public void RequestCall(CompletionQueueSafeHandle cq, BatchCompletionDelegate callback)
+        public void RequestCall(BatchCompletionDelegate callback, GrpcEnvironment environment)
         {
             var ctx = BatchContextSafeHandle.Create();
-            GrpcEnvironment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
-            grpcsharp_server_request_call(this, cq, ctx).CheckOk();
+            environment.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+            grpcsharp_server_request_call(this, environment.CompletionQueue, ctx).CheckOk();
         }
 
         protected override bool ReleaseHandle()

src/csharp/Grpc.Core/Server.cs

@@ -52,6 +52,7 @@ namespace Grpc.Core
         /// </summary>
         public const int PickUnusedPort = 0;
 
+        readonly GrpcEnvironment environment;
         readonly ServerSafeHandle handle;
         readonly object myLock = new object();
 
@@ -67,9 +68,10 @@ namespace Grpc.Core
         /// <param name="options">Channel options.</param>
         public Server(IEnumerable<ChannelOption> options = null)
         {
+            this.environment = GrpcEnvironment.GetInstance();
             using (var channelArgs = ChannelOptions.CreateChannelArgs(options))
             {
-                this.handle = ServerSafeHandle.NewServer(GetCompletionQueue(), channelArgs);
+                this.handle = ServerSafeHandle.NewServer(environment.CompletionQueue, channelArgs);
             }
         }
 
@@ -144,7 +146,7 @@ namespace Grpc.Core
                 shutdownRequested = true;
             }
 
-            handle.ShutdownAndNotify(GetCompletionQueue(), HandleServerShutdown);
+            handle.ShutdownAndNotify(HandleServerShutdown, environment);
             await shutdownTcs.Task;
             handle.Dispose();
         }
@@ -173,7 +175,7 @@ namespace Grpc.Core
                 shutdownRequested = true;
             }
 
-            handle.ShutdownAndNotify(GetCompletionQueue(), HandleServerShutdown);
+            handle.ShutdownAndNotify(HandleServerShutdown, environment);
             handle.CancelAllCalls();
             await shutdownTcs.Task;
             handle.Dispose();
@@ -208,7 +210,7 @@ namespace Grpc.Core
             {
                 if (!shutdownRequested)
                 {
-                    handle.RequestCall(GetCompletionQueue(), HandleNewServerRpc);
+                    handle.RequestCall(HandleNewServerRpc, environment);
                 }
             }
         }
@@ -225,7 +227,7 @@ namespace Grpc.Core
                 {
                     callHandler = new NoSuchMethodCallHandler();
                 }
-                await callHandler.HandleCall(method, call, GetCompletionQueue());
+                await callHandler.HandleCall(method, call, environment);
             }
             catch (Exception e)
             {
@@ -259,10 +261,5 @@ namespace Grpc.Core
         {
             shutdownTcs.SetResult(null);
         }
-
-        private static CompletionQueueSafeHandle GetCompletionQueue()
-        {
-            return GrpcEnvironment.ThreadPool.CompletionQueue;
-        }
     }
 }

src/csharp/Grpc.Examples.MathClient/MathClient.cs

@@ -39,8 +39,6 @@ namespace math
     {
         public static void Main(string[] args)
         {
-            GrpcEnvironment.Initialize();
-
             using (Channel channel = new Channel("127.0.0.1", 23456))
             {
                 Math.IMathClient stub = new Math.MathClient(channel);

src/csharp/Grpc.Examples.MathServer/MathServer.cs

@@ -42,8 +42,6 @@ namespace math
         {
             string host = "0.0.0.0";
 
-            GrpcEnvironment.Initialize();
-
             Server server = new Server();
             server.AddServiceDefinition(Math.BindService(new MathServiceImpl()));
             int port = server.AddListeningPort(host, 23456);

src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs

@@ -54,8 +54,6 @@ namespace math.Tests
         [TestFixtureSetUp]
         public void Init()
         {
-            GrpcEnvironment.Initialize();
-
             server = new Server();
             server.AddServiceDefinition(Math.BindService(new MathServiceImpl()));
             int port = server.AddListeningPort(host, Server.PickUnusedPort);
@@ -75,7 +73,6 @@ namespace math.Tests
         public void Cleanup()
         {
             channel.Dispose();
-
             server.ShutdownAsync().Wait();
             GrpcEnvironment.Shutdown();
         }

src/csharp/Grpc.IntegrationTesting/InteropClient.cs

@@ -102,8 +102,6 @@ namespace Grpc.IntegrationTesting
 
         private void Run()
         {
-            GrpcEnvironment.Initialize();
-
             Credentials credentials = null;
             if (options.useTls)
             {
@@ -135,7 +133,6 @@ namespace Grpc.IntegrationTesting
                 TestService.ITestServiceClient client = new TestService.TestServiceClient(channel, stubConfig);
                 RunTestCase(options.testCase, client);
             }
-
             GrpcEnvironment.Shutdown();
         }
 

src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs

@@ -55,8 +55,6 @@ namespace Grpc.IntegrationTesting
         [TestFixtureSetUp]
         public void Init()
         {
-            GrpcEnvironment.Initialize();
-
             server = new Server();
             server.AddServiceDefinition(TestService.BindService(new TestServiceImpl()));
             int port = server.AddListeningPort(host, Server.PickUnusedPort, TestCredentials.CreateTestServerCredentials());
@@ -74,7 +72,6 @@ namespace Grpc.IntegrationTesting
         public void Cleanup()
         {
             channel.Dispose();
-
             server.ShutdownAsync().Wait();
             GrpcEnvironment.Shutdown();
         }

src/csharp/Grpc.IntegrationTesting/InteropServer.cs

@@ -88,8 +88,6 @@ namespace Grpc.IntegrationTesting
 
         private void Run()
         {
-            GrpcEnvironment.Initialize();
-
             var server = new Server();
             server.AddServiceDefinition(TestService.BindService(new TestServiceImpl()));