Add support to restart Language Server

Signed-off-by: Siddharth Sharma <[email protected]>

README.md

@@ -27,13 +27,14 @@ by the extension, except pull diagnostics and commands.
 
 See `pyang` documentation corresponding to installation for expected features.
 
-See: [Programmatic Language Features][programmatic], [Language Server Extension Guide][lseg]
+See: [Programmatic Language Features][programmatic],
+     [Language Server Extension Guide][lseg]
 
 ## Requirements
 
 The extension requires a `pyang` version installation that supports LSP. At the
-time of writing, only a work in progress `pyang` supports `--lsp` argument,
-which is used to execute it as an LSP server.
+time of writing, only a work in progress `pyang` supports `--lsp --no-env-path`
+arguments, which are used to execute it as an LSP server.
 
 ## Extension Settings
 
@@ -52,22 +53,34 @@ This extension contributes the following settings:
 * `pyang.debug.server.port`
   > LSP Server Port, when LSP is used via TCP socket.
 
+## Extension Commands
+
+This extension contributes the following commands:
+
+* `pyang.client.restart`
+  > `pyang: Restart Language Server` restarts the language client and in turn
+  reinstantiates the language server. When `pyang.debug.server.enable` is set,
+  it merely reinitiates the TCP connection and hence TCP server should already
+  be initiated.
+
 ## Known Issues
 
 Missing `pyang` or older installations that do not meet requirements are not
 handled gracefully.
 
-Change of configuration requires reload of editor for application.
+Change of some settings e.g., CLI arguments, requires reload of manual reload of
+the editor. `pyang: Restart Language Server` command reuses the settings from
+the last startup.
 
 For issues pertaining to the language server, please refer to documentation for
 `pyang`.
 
-## Unknown Issues
+## Release Notes
 
-The extension has only been verified with VS Code, hence issues may exist with
-other VS Code compatible editors/IDE.
+### 0.2.0
 
-## Release Notes
+* Added support for older VS Code >= 1.65.0
+* Added command `pyang: Restart Language Server`
 
 ### 0.1.0
 

package.json

@@ -1,7 +1,7 @@
 {
     "name": "pyang",
     "displayName": "pyang",
-    "version": "0.1.0",
+    "version": "0.2.0",
     "publisher": "sid-sharma",
     "description": "YANG Language Support using pyang",
     "author": {
@@ -15,10 +15,13 @@
     ],
     "pricing": "Free",
     "engines": {
-        "vscode": "^1.88.0"
+        "vscode": "^1.65.0"
     },
     "license": "MIT",
-    "activationEvents": [],
+    "activationEvents": [
+        "onLanguage:yang",
+        "onCommand:pyang.client.restart"
+    ],
     "main": "./dist/extension",
     "contributes": {
         "languages": [
@@ -41,6 +44,13 @@
                 "path": "./syntaxes/yang.tmLanguage.json"
             }
         ],
+        "commands": [
+            {
+                "command": "pyang.client.restart",
+                "title": "Restart Language Server",
+                "category": "pyang"
+            }
+        ],
         "configuration": {
             "type": "object",
             "title": "pyang",

src/extension.ts

@@ -12,24 +12,40 @@ import {
 } from 'vscode-languageclient/node';
 
 let client: LanguageClient;
+const restartCmd = 'pyang.client.restart'
 const config = vscode.workspace.getConfiguration('pyang');
 const debug = config.get<boolean>('debug.server.enable', false)
-const debug_host = config.get<string>('debug.server.host', "127.0.0.1")
-const debug_port = config.get<number>('debug.server.port', 2087)
-const extra_args = config.get<string>('cli.args', '')
+const debugHost = config.get<string>('debug.server.host', "127.0.0.1")
+const debugPort = config.get<number>('debug.server.port', 2087)
+const extraArgs = config.get<string>('cli.args', '')
 
 export function activate(context: vscode.ExtensionContext) {
-    let clientOptions: LanguageClientOptions = {
+    const clientOptions: LanguageClientOptions = {
         documentSelector: ['yang'],
+        synchronize: {
+            fileEvents: vscode.workspace.createFileSystemWatcher('**/*.yang')
+        }
     };
     const clientId = { id: 'pyang', name: 'pyang Language Server' };
     client = debug
         ? getSocketLanguageClient(clientId, clientOptions)
-        : getStdioLanguageClient(clientId, clientOptions, context);
+        : getStdioLanguageClient(clientId, clientOptions);
+
     client.start();
-    vscode.window.showInformationMessage(debug
-        ? 'pyang: LSP socket mode'
-        : 'pyang: LSP stdio mode');
+
+    client.onReady().then(() => {
+        vscode.window.showInformationMessage(debug
+            ? 'pyang: LSP socket mode'
+            : 'pyang: LSP stdio mode');
+
+    });
+
+    const restartCmdHandler = async () => {
+        await client.stop();
+        client.start();
+    };
+
+    context.subscriptions.push(vscode.commands.registerCommand(restartCmd, restartCmdHandler));
 }
 
 export function deactivate(): Thenable<void> | undefined {
@@ -42,14 +58,13 @@ export function deactivate(): Thenable<void> | undefined {
 function getStdioLanguageClient(
     clientId: { id: string, name: string },
     clientOptions: LanguageClientOptions,
-    context: vscode.ExtensionContext
 ): LanguageClient {
     const lsp_command = 'pyang';
     let lsp_args = [
         '--lsp',
         '--no-env-path',
     ];
-    lsp_args = lsp_args.concat(extra_args.split(' '))
+    lsp_args = lsp_args.concat(extraArgs.split(' '))
     const serverOptions: ServerOptions = {
         run: {
             command: lsp_command,
@@ -73,13 +88,13 @@ function getSocketLanguageClient(
     clientId: { id: string, name: string },
     clientOptions: LanguageClientOptions,
 ): LanguageClient {
-    let connectionInfo = {
-        port: debug_port,
-        host: debug_host
+    const connectionInfo = {
+        port: debugPort,
+        host: debugHost
     };
-    let serverOptions: ServerOptions = () => {
-        let socket = net.connect(connectionInfo);
-        let result: StreamInfo = {
+    const serverOptions: ServerOptions = () => {
+        const socket = net.connect(connectionInfo);
+        const result: StreamInfo = {
             writer: socket,
             reader: socket
         };

test/yang/test-d.yang

@@ -1,2 +1,3 @@
 module test-d {
+  namespace "urn:test-c";
 }