Fix node debugger protocol (#358)

* Use legacy debugger for Node 6.10

* Document which debugger protocol to use

* Making Node8 debugging work

README.md

@@ -229,7 +229,7 @@ $ sam local invoke -d 5858 <function logical id>
 $ sam local start-api -d 5858
 ```
 
-Note: If using `sam local start-api`, the local API Gateway will expose all of your lambda functions but, since you can specify a single debug port, you can only debug one function at a time. You will need to hit your api before Sam Local binds to the port allowing the debugger to connect.
+Note: If using `sam local start-api`, the local API Gateway will expose all of your Lambda functions but, since you can specify a single debug port, you can only debug one function at a time. You will need to hit your API before SAM Local binds to the port allowing the debugger to connect.
 
 Here is an example showing how to debug a NodeJS function with Microsoft Visual Studio Code:
 
@@ -249,13 +249,13 @@ In order to setup Visual Studio Code for debugging with AWS SAM Local, use the f
             "port": 5858,
             "localRoot": "${workspaceRoot}",
             "remoteRoot": "/var/task",
-            "protocol": "inspector"
+            "protocol": "legacy"
         }
     ]
 }
 ``` 
 
-Note: You must detach your debugger in order for the result to be sent back to AWS SAM Local.
+Note: Node.js versions **below** 7 (e.g. Node.js 4.3 and Node.js 6.10) use the `legacy` protocol, while Node.js versions including and above 7 (e.g. Node.js 8.10) use the `inspector` protocol. Be sure to specify the corresponding protocol in the `protocol` entry of your launch configuration.
 
 #### Debugging Python functions
 

runtime.go

@@ -496,8 +496,7 @@ func (r *Runtime) getDebugEntrypoint() (overrides []string) {
 		}
 		overrides = append(overrides, debuggerArgsArray...)
 		overrides = append(overrides,
-			"--inspect="+r.DebugPort,
-			"--debug-brk",
+			"--debug-brk="+r.DebugPort,
 			"--nolazy",
 			"--max-old-space-size=2547",
 			"--max-semi-space-size=150",
@@ -511,8 +510,9 @@ func (r *Runtime) getDebugEntrypoint() (overrides []string) {
 		}
 		overrides = append(overrides, debuggerArgsArray...)
 		overrides = append(overrides,
-			"--inspect="+r.DebugPort,
-			"--debug-brk",
+			// Node8 requires the host to be explicitly set in order to bind to localhost instead of 127.0.0.1
+			// https://github.com/nodejs/node/issues/11591#issuecomment-283110138
+			"--inspect-brk=0.0.0.0:"+r.DebugPort,
 			"--nolazy",
 			"--expose-gc",
 			"--max-semi-space-size=150",