Debugger.md

How to debug lwnode

lwnode provides preliminary debugging capabilities via VS code. This document shows you how to debug a hello.js.

We assume lwnode is checked out in the lwnode directory in the following code example.

1. Setup VS Code for lwnode

1.1. Install Escargot Debug plugin

$ git clone https://github.com/Samsung/escargot-vscode-extension.git
$ cd escargot-vs-code-extension
$ npm install
$ npm install -g vsce
$ npm run compile
$ vsce package

// escargot-vscode-extension.vsix is created

1.2. Install escargot-vscode-extension.vsix

$ cd lwnode
$ code .

Install the plugin as follows:

• Type ctrl+shrt+p and type Extensions: Install from VSIX...
• Select escargot-vs-code-extension.vsix

1.3. Add the following debug configuration to .vscode/launch.json

$ cd lwnode
$ vi .vscode/launch.json

// .vscode/launch.json
{
    "version": "0.2.0",
    "configurations": [
        // Your existing targets may appear here.
        // Add the following target to your launch.json
        {
            "name": "Debug: lwnode",
            "type": "escargot",
            "request": "attach",
            "address": "localhost",
            "port": 6501,
            "localRoot": "${workspaceRoot}",
            "debugLog": 4
        }
    ]
}

2. Compile lwnode with debugger support

Compile lwnode with a debugger option.

$ cd lwnode
$ ./configure --debug --escargot-debugger
$ ninja -C out/linux/Debug lwnode

3. Run debugger with VS Code

3.1. Start a debug server on a new terminal

// Open a new terminal
$ cd lwnode
$ out/linux/Debug/lwnode --start-debug-server ./hello.js

A sample of hello.js is given below.

// hello.js
let sum = 0;
for (let i = 0; i < 10; i++) {
  sum += 1;
}

lwnode will wait for a connection from VS code.

3.2. Open hello.js in VS Code and run debugger

$ cd lwnode
$ code .

On VS Code, run as follows:

• Open hello.js in VS Code
• Select Run and Debug (ctrl+shift+D) on the left panel
• Set target to Debug: lwnode found on the top
• Select Run -> Start Debugging (F5) on the menu

Known Issues:

• The debugger by default stops at every *.js file loaded before loading hello.js. This behaviour is expected to be fixed in the next version. (i.e., the console.log() function will call many subsequence JS functions calls.)
• To add a break point, wait until hello.js is loaded in VS code, and add a break point.