Make ServerCallContext.Peer lazy

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

@@ -76,7 +76,7 @@ namespace Grpc.Core.Internal
 
             Status status;
             Tuple<TResponse,WriteFlags> responseTuple = null;
-            var context = HandlerUtils.NewContext(newRpc, asyncCall.Peer, responseStream, asyncCall.CancellationToken);
+            var context = HandlerUtils.NewContext(newRpc, responseStream, asyncCall.CancellationToken);
             try
             {
                 GrpcPreconditions.CheckArgument(await requestStream.MoveNext().ConfigureAwait(false));
@@ -134,7 +134,7 @@ namespace Grpc.Core.Internal
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
 
             Status status;
-            var context = HandlerUtils.NewContext(newRpc, asyncCall.Peer, responseStream, asyncCall.CancellationToken);
+            var context = HandlerUtils.NewContext(newRpc, responseStream, asyncCall.CancellationToken);
             try
             {
                 GrpcPreconditions.CheckArgument(await requestStream.MoveNext().ConfigureAwait(false));
@@ -193,7 +193,7 @@ namespace Grpc.Core.Internal
 
             Status status;
             Tuple<TResponse,WriteFlags> responseTuple = null;
-            var context = HandlerUtils.NewContext(newRpc, asyncCall.Peer, responseStream, asyncCall.CancellationToken);
+            var context = HandlerUtils.NewContext(newRpc, responseStream, asyncCall.CancellationToken);
             try
             {
                 var response = await handler(requestStream, context).ConfigureAwait(false);
@@ -250,7 +250,7 @@ namespace Grpc.Core.Internal
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
 
             Status status;
-            var context = HandlerUtils.NewContext(newRpc, asyncCall.Peer, responseStream, asyncCall.CancellationToken);
+            var context = HandlerUtils.NewContext(newRpc, responseStream, asyncCall.CancellationToken);
             try
             {
                 await handler(requestStream, responseStream, context).ConfigureAwait(false);
@@ -324,13 +324,13 @@ namespace Grpc.Core.Internal
             return writeOptions != null ? writeOptions.Flags : default(WriteFlags);
         }
 
-        public static ServerCallContext NewContext<TRequest, TResponse>(ServerRpcNew newRpc, string peer, ServerResponseStream<TRequest, TResponse> serverResponseStream, CancellationToken cancellationToken)
+        public static ServerCallContext NewContext<TRequest, TResponse>(ServerRpcNew newRpc, ServerResponseStream<TRequest, TResponse> serverResponseStream, CancellationToken cancellationToken)
             where TRequest : class
             where TResponse : class
         {
             DateTime realtimeDeadline = newRpc.Deadline.ToClockType(ClockType.Realtime).ToDateTime();
 
-            return new ServerCallContext(newRpc.Call, newRpc.Method, newRpc.Host, peer, realtimeDeadline,
+            return new ServerCallContext(newRpc.Call, newRpc.Method, newRpc.Host, realtimeDeadline,
                 newRpc.RequestMetadata, cancellationToken, serverResponseStream.WriteResponseHeadersAsync, serverResponseStream);
         }
     }

src/csharp/Grpc.Core/ServerCallContext.cs

@@ -48,7 +48,6 @@ namespace Grpc.Core
         private readonly CallSafeHandle callHandle;
         private readonly string method;
         private readonly string host;
-        private readonly string peer;
         private readonly DateTime deadline;
         private readonly Metadata requestHeaders;
         private readonly CancellationToken cancellationToken;
@@ -58,13 +57,12 @@ namespace Grpc.Core
         private Func<Metadata, Task> writeHeadersFunc;
         private IHasWriteOptions writeOptionsHolder;
 
-        internal ServerCallContext(CallSafeHandle callHandle, string method, string host, string peer, DateTime deadline, Metadata requestHeaders, CancellationToken cancellationToken,
+        internal ServerCallContext(CallSafeHandle callHandle, string method, string host, DateTime deadline, Metadata requestHeaders, CancellationToken cancellationToken,
             Func<Metadata, Task> writeHeadersFunc, IHasWriteOptions writeOptionsHolder)
         {
             this.callHandle = callHandle;
             this.method = method;
             this.host = host;
-            this.peer = peer;
             this.deadline = deadline;
             this.requestHeaders = requestHeaders;
             this.cancellationToken = cancellationToken;
@@ -115,7 +113,10 @@ namespace Grpc.Core
         {
             get
             {
-                return this.peer;
+                // Getting the peer lazily is fine as the native call is guaranteed
+                // not to be disposed before user-supplied server side handler returns.
+                // Most users won't need to read this field anyway.
+                return this.callHandle.GetPeer();
             }
         }