Support V8 Inspector Integration for Node.js

Addresses #796

src/Microsoft.AspNetCore.NodeServices/HostingModels/OutOfProcessNodeInstance.cs

@@ -27,16 +27,6 @@ namespace Microsoft.AspNetCore.NodeServices.HostingModels
         protected readonly ILogger OutputLogger;
 
         private const string ConnectionEstablishedMessage = "[Microsoft.AspNetCore.NodeServices:Listening]";
-        private const string DebuggingStartedMessageFormat = @"-----
-*** Node.js debugging is enabled ***
-{0}
-
-To debug, run:
-   node-inspector{1}
-
-If you haven't yet installed node-inspector, you can do so as follows:
-   npm install -g node-inspector
------";
         private readonly TaskCompletionSource<object> _connectionIsReadySource = new TaskCompletionSource<object>();
         private bool _disposed;
         private readonly StringAsTempFile _entryPointScript;
@@ -215,8 +205,8 @@ If you haven't yet installed node-inspector, you can do so as follows:
         /// <param name="projectPath">The root path of the project. This is used when locating Node.js modules relative to the project root.</param>
         /// <param name="commandLineArguments">Command-line arguments to be passed to the Node.js process.</param>
         /// <param name="environmentVars">Environment variables to be set on the Node.js process.</param>
-        /// <param name="launchWithDebugging">If true, passes a flag to the Node.js process telling it to accept V8 debugger connections.</param>
+        /// <param name="launchWithDebugging">If true, passes a flag to the Node.js process telling it to accept V8 Inspector connections.</param>
-        /// <param name="debuggingPort">If debugging is enabled, the Node.js process should listen for V8 debugger connections on this port.</param>
+        /// <param name="debuggingPort">If debugging is enabled, the Node.js process should listen for V8 Inspector connections on this port.</param>
         /// <returns></returns>
         protected virtual ProcessStartInfo PrepareNodeProcessStartInfo(
             string entryPointFilename, string projectPath, string commandLineArguments,
@@ -226,7 +216,7 @@ If you haven't yet installed node-inspector, you can do so as follows:
             string debuggingArgs;
             if (launchWithDebugging)
             {
-                debuggingArgs = debuggingPort != default(int) ? $"--debug={debuggingPort} " : "--debug ";
+                debuggingArgs = debuggingPort != default(int) ? $"--inspect={debuggingPort} " : "--inspect ";
                 _nodeDebuggingPort = debuggingPort;
             }
             else
@@ -389,10 +379,13 @@ If you haven't yet installed node-inspector, you can do so as follows:
             {
                 if (evt.Data != null)
                 {
-                    if (IsDebuggerListeningMessage(evt.Data))
+                    if (IsDebuggerMessage(evt.Data))
                     {
-                        var debugPortArg = _nodeDebuggingPort.HasValue ? $" --debug-port={_nodeDebuggingPort.Value}" : string.Empty;
+                        OutputLogger.LogWarning(evt.Data);
-                        OutputLogger.LogWarning(string.Format(DebuggingStartedMessageFormat, evt.Data, debugPortArg));
+                    }
+                    else if (IsWarning(evt.Data))
+                    {
+                        OutputLogger.LogWarning(evt.Data);
                     }
                     else if (!initializationIsCompleted)
                     {
@@ -411,9 +404,17 @@ If you haven't yet installed node-inspector, you can do so as follows:
             _nodeProcess.BeginErrorReadLine();
         }
 
-        private static bool IsDebuggerListeningMessage(string message)
+        private static bool IsDebuggerMessage(string message)
         {
-            return message.StartsWith("Debugger listening ", StringComparison.OrdinalIgnoreCase);
+            return message.StartsWith("Debugger attached", StringComparison.OrdinalIgnoreCase) ||
+                message.StartsWith("Debugger listening ", StringComparison.OrdinalIgnoreCase) ||
+                message.StartsWith("To start debugging", StringComparison.OrdinalIgnoreCase) ||
+                message.Contains("chrome-devtools:");
+        }
+
+        private static bool IsWarning(string message)
+        {
+            return message.StartsWith("Warning:", StringComparison.OrdinalIgnoreCase);
         }
 
         private FileSystemWatcher BeginFileWatcher(string rootDir)

src/Microsoft.AspNetCore.SpaServices/README.md

@@ -788,14 +788,14 @@ Caveats:
 
 ## Debugging your JavaScript/TypeScript code when it runs on the server
 
-When you're using NodeServices or the server-side prerendering feature included in the project templates in this repo, your JavaScript/TypeScript code will execute on the server in a background instance of Node.js. You can enable debugging on that Node.js instance. Here's how to do it.
+When you're using NodeServices or the server-side prerendering feature included in the project templates in this repo, your JavaScript/TypeScript code will execute on the server in a background instance of Node.js. You can enable debugging via [V8 Inspector Integration](https://nodejs.org/api/debugger.html#debugger_v8_inspector_integration_for_node_js) on that Node.js instance. Here's how to do it.
 
 First, in your `Startup.cs` file, in the `ConfigureServices` method, add the following:
 
 ```
 services.AddNodeServices(options => {
     options.LaunchWithDebugging = true;
-    options.DebuggingPort = 5858;
+    options.DebuggingPort = 9229;
 });
 ```
 
@@ -803,21 +803,20 @@ Now, run your application from that command line (e.g., `dotnet run`). Then in a
 
 In the console, you should see all the normal trace messages appear, plus among them will be:
 
-      -----
+```
-      *** Node.js debugging is enabled ***
+warn: Microsoft.AspNetCore.NodeServices[0]
-      Debugger listening on port 5858
+      Debugger listening on port 9229.
+warn: Microsoft.AspNetCore.NodeServices[0]
+      Warning: This is an experimental feature and could change at any time.
+warn: Microsoft.AspNetCore.NodeServices[0]
+      To start debugging, open the following URL in Chrome:
+warn: Microsoft.AspNetCore.NodeServices[0]
+          chrome-devtools://devtools/bundled/inspector.html?experiments=true&v8only=true&ws=127.0.0.1:9229/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+```
 
-      To debug, run:
+As per instructions open the URL in Chrome. Alternatively you can go to the `Sources` tab of the Dev Tools (at http://localhost:5000) and connect to the Node instance under `Threads` in the right sidebar.
-         node-inspector
-      
-      If you haven't yet installed node-inspector, you can do so as follows:
-         npm install -g node-inspector
-      -----
 
-In some other command line window, follow those instructions (i.e., install `node-inspector` as it describes, then run `node-inspector`). Then you can open a browser at `http://127.0.0.1:8080/?port=5858` and you'll see the debugger UI.
+By expanding the `webpack://` entry in the sidebar, you'll be able to find your original source code (it's using source maps), and then set breakpoints in it. When you re-run your app in another browser window, your breakpoints will be hit, then you can debug the server-side execution just like you'd debug client-side execution. It looks like this:
 
-By expanding the `webpack://` entry in the sidebar, you'll be able to find your original TypeScript code (it's using source maps), and then set breakpoints in it. When you re-run your app in another browser window, your breakpoints will be hit, then you can debug the server-side execution just like you'd debug client-side execution. It looks like this:
+![screenshot from 2017-03-25 13-33-26](https://cloud.githubusercontent.com/assets/1596280/24324604/ab888a7e-115f-11e7-89d1-1586acf5e35c.png)
 
-![screen shot 2016-07-26 at 18 56 12](https://cloud.githubusercontent.com/assets/1101362/17149317/a6f7d00c-5362-11e6-969c-4c3a9bbc33f7.png)
-
-(Note: although this looks like Chrome's native debugger for client-side code, it is actually a JavaScript-powered debugger UI that's connected to the server-side runtime)