Enable debug in development (OpenLiberty#310)

* Enable debug for Liberty LS and Jakarta LS in dev environment

* Add instructions for attaching debugger in VSCode

DEVELOPING.md

@@ -30,8 +30,8 @@ Ensure you have [Node.js and npm](https://docs.npmjs.com/downloading-and-install
      - Navigate to the Extensions activity bar, or use the shortcut `Ctrl`-`Shift`-`X`
      - Click the `...` dropdown menu and select `Install from VSIX` and choose the generated `liberty-tools-vscode-xxx.vsix` file
 
-Step 5 downloads the JARs for Liberty Config Language Server and Eclipse LSP4Jakarta that are consumed by the VS Code client.
-If you would like a different version of the language servers other than what is available to download, the following instructions explain how to build these JARs locally. Then rerun steps 6 and 7.
+> Step 5 downloads the JARs for Liberty Config Language Server and Eclipse LSP4Jakarta that are consumed by the VS Code client.
+If you would like a different version of the language servers other than what is available to download, the following instructions explain how to build these JARs locally.
 
 ## Language Servers
 
@@ -53,6 +53,17 @@ For more information on building Liberty Config Language Server, see the project
 
 For more information on building Eclipse LSP4Jakarta, see the project documentation on [GitHub](https://github.com/eclipse/lsp4jakarta/blob/main/docs/BUILDING.md). Note that there are [prerequisites](https://github.com/eclipse/lsp4jakarta/blob/main/docs/BUILDING.md#prerequisites) to building this project locally.
 
+### Debugging Language Servers
+When running the extension with locally built language servers, a debugger can be attached to the language server process.
+The debug ports are as follows:
+
+- Liberty-LemminX: `1054`
+- Liberty Language Server: `8002`
+- Jakarta LS: `8003`
+
+
+With the `liberty-language-server` project opened in VSCode, run `Debug attach liberty-ls` or `Debug attach liberty-lemminx` to attach the respective debugger to the running extension.
+
 ## Localization
 
 ### package.json

src/util/javaServerStarter.ts

@@ -21,10 +21,11 @@ import { workspace } from 'vscode';
 import { Executable, ExecutableOptions } from 'vscode-languageclient/node';
 import { RequirementsData } from './requirements';
 import * as glob from 'glob';
-import {LIBERTY_LS_JAR} from '../extension'
+import {JAKARTA_LS_JAR, LIBERTY_LS_JAR} from '../extension'
 
-// const DEBUG = startedInDebugMode();
-const LIBERTY_LS_DEBUG_PORT = 1064;
+const DEBUG = startedInDebugMode();
+const LIBERTY_LS_DEBUG_PORT = 8002;
+const JAKARTA_LS_DEBUG_PORT = 8003;
 
 // Referenced:
 // https://github.com/redhat-developer/vscode-microprofile/blob/master/src/languageServer/javaServerStarter.ts
@@ -42,19 +43,15 @@ export function prepareExecutable(jarName: string, requirements: RequirementsDat
 function prepareParams(jarName: string): string[] {
   const params: string[] = [];
 
-    // TODO: debug doesn't work yet
-//   if (DEBUG) {
-//     if (process.env.SUSPEND_SERVER === 'true') {
-//       params.push(`-agentlib:jdwp=transport=dt_socket,server=y,address=${DEBUG_PORT}`);
-//     } else {
-//       params.push(`-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=${DEBUG_PORT},quiet=y`);
-//     }
-//   }
-
-  // uncomment to debug the Liberty Config Language Server
-  // if (jarName === LIBERTY_LS_JAR) {
-  //   params.push(`-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=${LIBERTY_LS_DEBUG_PORT}`);
-  // }
+  // will only add debug args when run in development, not when run as an extension
+  if (DEBUG) {
+    if (jarName === LIBERTY_LS_JAR) {
+      params.push(`-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=${LIBERTY_LS_DEBUG_PORT},quiet=y`);
+    }
+    else if (jarName === JAKARTA_LS_JAR) {
+      params.push(`-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=${JAKARTA_LS_DEBUG_PORT},quiet=y`);
+    } 
+  }
 
   const jarHome = path.resolve(__dirname, "../jars");
   params.push('-jar');