Design review: Change AddNodeServices to take an Action<NodeServicesOptions> like other aspects of MVC DI config

src/Microsoft.AspNetCore.NodeServices/Configuration/NodeServicesFactory.cs

@@ -0,0 +1,43 @@
+using System;
+using Microsoft.AspNetCore.NodeServices.HostingModels;
+
+namespace Microsoft.AspNetCore.NodeServices
+{
+    public static class NodeServicesFactory
+    {
+        public static INodeServices CreateNodeServices(NodeServicesOptions options)
+        {
+            if (options == null)
+            {
+                throw new ArgumentNullException(nameof (options));
+            }
+            
+            return new NodeServicesImpl(() => CreateNodeInstance(options));
+        }
+
+        private static INodeInstance CreateNodeInstance(NodeServicesOptions options)
+        {
+            if (options.NodeInstanceFactory != null)
+            {
+                // If you've explicitly supplied an INodeInstance factory, we'll use that. This is useful for
+                // custom INodeInstance implementations.
+                return options.NodeInstanceFactory();
+            }
+            else
+            {
+                switch (options.HostingModel)
+                {
+                    case NodeHostingModel.Http:
+                        return new HttpNodeInstance(options.ProjectPath, options.WatchFileExtensions, options.NodeInstanceOutputLogger, 
+                            options.EnvironmentVariables, options.LaunchWithDebugging, options.DebuggingPort, /* port */ 0);
+                    case NodeHostingModel.Socket:
+                        var pipeName = "pni-" + Guid.NewGuid().ToString("D"); // Arbitrary non-clashing string
+                        return new SocketNodeInstance(options.ProjectPath, options.WatchFileExtensions, pipeName, options.NodeInstanceOutputLogger,
+                            options.EnvironmentVariables, options.LaunchWithDebugging, options.DebuggingPort);
+                    default:
+                        throw new ArgumentException("Unknown hosting model: " + options.HostingModel);
+                }
+            }
+        }
+    }
+}