Add Tarantool debugging facilities

This patch introduces basic Tarantool debugging facilities into the
extension. Basically it is done using EmmyLuaDebugger [^1].

Set up the debugger using the following instructions.

* Insert debugger code in Tarantool application by pressing
  `Ctrl+Shift+P` (or `Cmd+Shift+P` on MacOS) and running `Tarantool:
  Insert debugger code` command.
* Start single Tarantool instance.
* Press `F5` or run `Debug: Start debugging` command by pressing
  `Ctrl+Shift+P` (or `Cmd+Shift+P` on MacOS).
* Choose `EmmyLua New Debugger` in the list. This debugging
  configuration would run automatically from now.
* Set up breakpoints & access the Tarantool instance through `Debug
  console` in the bottom panel.

These features are supported.

* Breakpoints.
* Step-by-step execution within the fiber.
* Multiple files support.
* Interacting with the local variables, console at the debug mode.

Needs EmmyLua/EmmyLuaDebugger#75 to be tested
on MacOS on arm64.

Closes #19

[^1] EmmyLua/EmmyLuaDebugger#75

Author: georgiy-belyanin

CHANGELOG.md

@@ -8,6 +8,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Support for debugging Tarantool code using
+  [EmmyLuaDebugger](https://github.com/EmmyLua/EmmyLuaDebugger).
+
 ## [0.2.0] - 28.05.2025
 
 ### Added

README.md

@@ -8,7 +8,7 @@
  <img src="https://avatars2.githubusercontent.com/u/2344919?v=2&s=100" align="right">
 </a>
 
-Tarantool VS Code Extension helps you to develop Tarantool applications in VS Code. It enhances your text editor with completions, suggestions, and snippets.
+Tarantool VS Code Extension helps you to develop Tarantool applications in VS Code. It enhances your text editor with completions, suggestions, snippets, and Lua debugger.
 
 ---
 
@@ -22,6 +22,7 @@ This extension offers the following features.
 * Cluster configuration schema validation for Tarantool 3.0+.
 * [tt cluster management utility](https://github.com/tarantool/tt) inside the command palette.
 * Other auxiliary commands, e.g. install Tarantool of a specific version right from VS Code.
+* Debugger for Tarantool apps, allowing breakpoints, step-by-step execution, viewing local variables and Lua code execution.
 
 ---
 
@@ -31,7 +32,6 @@ That's how you use this extension.
 
 * Install the extension from the VS Code marketplace.
 * Open a Tarantool project in VS Code.
-* Run `Tarantool: Initialize VS Code extension in existing app` command from the command palette (`Ctrl+Shift+P` or `Cmd+Shift+P` on macOS).
 
 You may statically type your Lua functions as follows.
 
@@ -54,6 +54,16 @@ local unnamed_user = { name = 'Unnamed' }
 
 For more examples, refer to [the examples folder](examples/) with tutorials on how to type your Lua code.
 
+## Using debugger
+
+Tarantool VS Code extension provides debugger facility for developing Tarantool applications. It is employs EmmyLuaDebugger that is a stop-the-world Lua debugger.
+
+* Insert debugger code in Tarantool application by pressing `Ctrl+Shift+P` (or `Cmd+Shift+P` on MacOS) and running `Tarantool: Insert debugger code` command.
+* Start single Tarantool instance.
+* Press `F5` or run `Debug: Start debugging` command by pressing `Ctrl+Shift+P` (or `Cmd+Shift+P` on MacOS).
+* Choose `EmmyLua New Debugger` in the list. This debugging configuration would run automatically from now.
+* Set up breakpoints & access the Tarantool instance through `Debug console` in the bottom panel.
+
 ## Contributing
 
 Feel free to open issues on feature requests, wrong type annotations and bugs. If you're dealing with a problem related to LSP we'd appreciate addressing a direct issue to [the used external Lua Language server](https://github.com/CppCXY/emmylua-analyzer-rust).

package.json

@@ -61,6 +61,10 @@
       {
         "command": "tarantool.install-ce",
         "title": "Tarantool: Install Tarantool Community Edition (tt)"
+      },
+      {
+        "command": "tarantool.debugger-code",
+        "title": "Tarantool: Insert debugger code"
       }
     ],
     "yamlValidation": [

src/extension.ts

@@ -115,6 +115,7 @@ export function activate(context: vscode.ExtensionContext) {
 		{ name: 'stat', cb: tt.stat },
 		{ name: 'restart', cb: tt.restart },
 		{ name: 'install-ce', cb: tt.installCe },
+		{ name: 'debugger-code', cb: utils.insertDebuggerCode },
 	];
 
 	commands.forEach((command) => {

src/utils.ts

@@ -1,4 +1,5 @@
 import * as vscode from 'vscode';
+import * as path from 'path';
 
 export function fetchWsFolder(opts?: { showWarning?: boolean }): vscode.WorkspaceFolder | null {
 	const file = vscode.window.activeTextEditor?.document.uri.fsPath;
@@ -21,3 +22,68 @@ export function fetchWsFolder(opts?: { showWarning?: boolean }): vscode.Workspac
 
 	return wsFolder;
 }
+
+const dllPathTemplate = '{dllPath}';
+const debuggerCodeSnippet = `-- Start of Tarantool debugger block. Remove after debugging.
+do
+    local old_cpath = package.cpath
+    package.cpath = package.cpath .. ";${dllPathTemplate}"
+    rawset(_G, 'tolua', false)
+    rawset(_G, 'xlua', false)
+    rawset(_G, 'emmyHelper', {})
+    local dbg = require('emmy_core')
+    local log = require('log')
+    _G.emmyHelperInit()
+    function init_debugger()
+        dbg.tcpListen('localhost', 9966)
+        dbg.waitIDE()
+    end
+    local ok, err = pcall(init_debugger)
+    if ok then
+        log.info('Set up Tarantool for debugging')
+    else
+        log.warn('Unable to start debugger: %s', err)
+    end
+    package.cpath  = old_cpath
+end
+-- End of Tarantool debugger block. Remove after debugging.
+`;
+
+export async function insertDebuggerCode() {
+    const activeEditor = vscode.window.activeTextEditor;
+    if (!activeEditor) {
+        vscode.window.showWarningMessage(`You should have an active text editor window to insert Tarantool debugger code. Consider opening a file`);
+        return;
+    }
+    const document = activeEditor.document;
+    if (document.languageId !== 'lua') {
+        vscode.window.showWarningMessage(`Tarantool Debugger code is supposed to be used within .lua files`);
+        return;
+    }
+
+    let dllPath = '';
+    const extensionPath = __dirname;
+    const isWindows = process.platform === 'win32';
+    const isMac = process.platform === 'darwin';
+    const isLinux = process.platform === 'linux';
+    if (isWindows) {
+        const arch = await vscode.window.showQuickPick(['x64', 'x86']);
+        if (!arch) {
+            return;
+        }
+        dllPath = path.join(extensionPath, `debugger/emmy/windows/${arch}/?.dll`);
+    } else if (isMac) {
+        const arch = await vscode.window.showQuickPick(['x64', 'arm64']);
+        if (!arch) {
+            return;
+        }
+        dllPath = path.join(extensionPath, `debugger/emmy/mac/${arch}/emmy_core.dylib`);
+    }
+    else if (isLinux) {
+        dllPath = path.join(extensionPath, `debugger/emmy/linux/emmy_core.so`);
+    }
+
+    const snippet = new vscode.SnippetString();
+    snippet.appendText(debuggerCodeSnippet.replace(dllPathTemplate, dllPath.replace(/\\/g, '/')));
+    activeEditor.insertSnippet(snippet);
+}