[Code] Use different connect direction for ctags langserver (#38659)

x-pack/plugins/code/server/lsp/ctags_launcher.ts

@@ -4,43 +4,50 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
+import getPort from 'get-port';
+import { spawn } from 'child_process';
 import { ServerOptions } from '../server_options';
 import { LoggerFactory } from '../utils/log_factory';
-import { ILanguageServerLauncher } from './language_server_launcher';
 import { LanguageServerProxy } from './proxy';
+import { Logger } from '../log';
 import { RequestExpander } from './request_expander';
+import { AbstractLauncher } from './abstract_launcher';
 
-export class CtagsLauncher implements ILanguageServerLauncher {
+const CTAGS_LANG_DETACH_PORT = 2092;
+export class CtagsLauncher extends AbstractLauncher {
   private isRunning: boolean = false;
   constructor(
     readonly targetHost: string,
     readonly options: ServerOptions,
     readonly loggerFactory: LoggerFactory
-  ) {}
+  ) {
+    super('ctags', targetHost, options, loggerFactory);
+  }
   public get running(): boolean {
     return this.isRunning;
   }
 
-  public async launch(builtinWorkspace: boolean, maxWorkspace: number, installationPath: string) {
-    const port = 2092;
-
-    const log = this.loggerFactory.getLogger(['code', `ctags@${this.targetHost}:${port}`]);
-    const proxy = new LanguageServerProxy(port, this.targetHost, log, this.options.lsp);
-
-    log.info('Detach mode, expected ctags langserver launch externally');
-    proxy.onConnected(() => {
-      this.isRunning = true;
-    });
-    proxy.onDisconnected(() => {
-      this.isRunning = false;
-      if (!proxy.isClosed) {
-        log.warn('ctags language server disconnected, reconnecting');
-        setTimeout(() => proxy.connect(), 1000);
-      }
-    });
-
-    proxy.listen();
-    await proxy.connect();
+  createExpander(
+    proxy: LanguageServerProxy,
+    builtinWorkspace: boolean,
+    maxWorkspace: number
+  ): RequestExpander {
     return new RequestExpander(proxy, builtinWorkspace, maxWorkspace, this.options);
   }
+
+  startConnect(proxy: LanguageServerProxy) {
+    proxy.awaitServerConnection();
+  }
+
+  async getPort(): Promise<number> {
+    if (!this.options.lsp.detach) {
+      return await getPort();
+    }
+    return CTAGS_LANG_DETACH_PORT;
+  }
+
+  async spawnProcess(installationPath: string, port: number, log: Logger) {
+    // TODO(pcxu): add spawn command here for ctags langserver
+    return spawn('');
+  }
 }