A few external server/docker improvements (#255)

* Fix lockup when external server not present on startup

* Clean up restart command

Disposing checks if the server actually needs stopping.
Using dispose prevents trying to stop the connection when the underlying
socket is already gone. VSCode sends a shutdown command and marks the
client as `Stopping`. But Aquiring the connection never resolves or errors
resulting in the language server never actually restarting

* Offer users to try connecting again for external clients

Co-authored-by: Fred Snyder <[email protected]>

src/extension.ts

@@ -89,19 +89,11 @@ export function activate(context: vscode.ExtensionContext) {
 		context.subscriptions.push(disposableClient);
 	};
 
-	var restartLanguageServer = function (): Promise<void> {
-		return new Promise((resolve) => {
-			if (languageClient) {
-				languageClient.stop().then(() => {
-					disposableClient.dispose();
-					startLanguageServer();
-					resolve();
-				});
-			} else {
-				startLanguageServer();
-				resolve();
-			}
-		});
+	var restartLanguageServer = function (): void {
+		if (disposableClient) {
+			disposableClient.dispose();
+		}
+		startLanguageServer();
 	};
 
 	// Open URL command (used internally for browsing documentation pages)
@@ -115,9 +107,8 @@ export function activate(context: vscode.ExtensionContext) {
 
 	// Restart command
 	var disposableRestart = vscode.commands.registerCommand('solargraph.restart', () => {
-		restartLanguageServer().then(() => {
-			vscode.window.showInformationMessage('Solargraph server restarted.');
-		});
+		restartLanguageServer();
+		vscode.window.showInformationMessage('Solargraph server restarted.');
 	});
 	context.subscriptions.push(disposableRestart);
 

src/language-client.ts

@@ -100,12 +100,43 @@ export function makeLanguageClient(configuration: solargraph.Configuration): Lan
 				});
 			};
 		} else {
-			return () => {
-				return new Promise((resolve) => {
+			var getSocket = function(): Promise<net.Socket> {
+				return new Promise((resolve, reject) => {
 					let socket: net.Socket = net.createConnection({ host: vscode.workspace.getConfiguration('solargraph').externalServer.host, port: parseInt(vscode.workspace.getConfiguration('solargraph').externalServer.port) });
-					resolve({
-						reader: socket,
-						writer: socket
+					let errorHandler = function(err: Error) {
+						reject(err);
+					};
+					socket.addListener('connect', () => {
+						socket.removeListener('error', errorHandler);
+						resolve(socket);
+					});
+					socket.addListener('error', errorHandler);
+				});
+			};
+			var getSocketOrNotifyUser = function(): Promise<net.Socket> {
+				return new Promise((resolve, reject) => {
+					getSocket().then((socket) => {
+						resolve(socket);
+					}).catch((err) => {
+						vscode.window.showWarningMessage('Failed to connect to the external language client: ' + err.message, 'Try again').then((item) => {
+							if(item === 'Try again') {
+								resolve(getSocketOrNotifyUser());
+							} else {
+								reject(err);
+							}
+						});
+					});
+				});
+			};
+			return () => {
+				return new Promise((resolve, reject) => {
+					getSocketOrNotifyUser().then((socket) => {
+						resolve({
+							reader: socket,
+							writer: socket
+						});
+					}).catch((err) => {
+						reject(err);
 					});
 				});
 			};