Use the python extension venv (#820)

Summary:
Fixes #6
Fixes #645
Fixes #183

If [the VsCode Python extension](https://marketplace.visualstudio.com/items?itemName=ms-python.python) is installed, use the Python interpreter that is selected in the extension to start the pyre language server. Also, subscribe to environment switches and restart the pyre language server with the new environments.

If the extension is not present, we retain the original behaviour of the extension.

This is very useful for people that may have multiple environments installed but is more useful for people that use the VsCode SSH extension and cannot benefit from [this workaround](#6 (comment)).

Pull Request resolved: #820

Test Plan: I ran the extension locally and it seems to be picking up the interpreter path.

Reviewed By: stroxler, inseokhwang

Differential Revision: D56205532

Pulled By: kinto0

fbshipit-source-id: dc0c00f5a41d37c5cb7d9f85a60ac0ba9230456a

tools/ide_plugins/vscode/.gitignore

@@ -0,0 +1,3 @@
+**/out
+**/.vscode-test
+*.vsix

tools/ide_plugins/vscode/package.json

@@ -1,6 +1,6 @@
 {
   "name": "pyre-vscode",
-  "version": "0.0.1",
+  "version": "0.0.2",
   "publisher": "fb-pyre-check",
   "engines": {
     "vscode": "^1.15.0"
@@ -26,15 +26,18 @@
     "lint": "tslint --force -p ."
   },
   "dependencies": {
-    "vscode-languageclient": "^3.5.0"
+    "@vscode/python-extension": "^1.0.5",
+    "vscode-languageclient": "^3.5.0",
+    "which": "^4.0.0"
   },
   "devDependencies": {
     "@types/mocha": "^2.2.44",
     "@types/node": "^8.0.53",
+    "@types/which": "^3.0.4",
     "cson": "^4.1.0",
     "tslint": "^5.8.0",
     "tslint-microsoft-contrib": "^5.0.1",
-    "typescript": "^2.6.1",
+    "typescript": "^3.7",
     "vscode": "^1.1.7"
   }
 }

tools/ide_plugins/vscode/src/main.ts

@@ -11,34 +11,60 @@
 
 import * as vscode from 'vscode';
 import { LanguageClient, LanguageClientOptions, DidChangeConfigurationNotification } from 'vscode-languageclient';
+import { EnvironmentPath, PVSC_EXTENSION_ID, PythonExtension } from '@vscode/python-extension'
+import { dirname, join } from 'path';
+import { existsSync, statSync } from 'fs';
+import which from 'which';
 
-let languageClient: LanguageClient;
+type LanguageClientState = {
+	languageClient: LanguageClient,
+	configListener: Promise<vscode.Disposable>
+}
 
-namespace Configuration {
+// Extension state
+let state : LanguageClientState | undefined;
+let envListener: vscode.Disposable | undefined;
 
-	let configurationListener: vscode.Disposable;
+let outputChannel = vscode.window.createOutputChannel("pyre");
 
-	export function initialize() {
-		configurationListener = vscode.workspace.onDidChangeConfiguration(() => {
-			languageClient.sendNotification(DidChangeConfigurationNotification.type, { settings: null });
-		});
+export async function activate(_: vscode.ExtensionContext) {
+
+	const pythonExtension = vscode.extensions.getExtension<PythonExtension>(PVSC_EXTENSION_ID);
+
+	if (!pythonExtension) {
+		outputChannel.appendLine("Python extension not found. Will use the default console environment.");
+		state = createLanguageClient('pyre');
+		outputChannel.appendLine("Done");
+		return;
 	}
 
-	export function dispose() {
-		if (configurationListener) {
-			configurationListener.dispose();
-		}
+	const activatedEnvPath = pythonExtension.exports.environments.getActiveEnvironmentPath();
+	const pyrePath = await findPyreCommand(activatedEnvPath);
+
+	if (pyrePath) {
+		state = createLanguageClient(pyrePath);
 	}
+
+	envListener = pythonExtension.exports.environments.onDidChangeActiveEnvironmentPath(async (e) => {
+		state?.languageClient?.stop();
+		state?.configListener.then((listener) => listener.dispose());
+		state = undefined;
+
+		const pyrePath = await findPyreCommand(e);
+		if (pyrePath) {
+			state = createLanguageClient(pyrePath);
+		}
+	});
 }
 
-export async function activate(_: vscode.ExtensionContext) {
+function createLanguageClient(pyrePath: string) : LanguageClientState {
 
-	let serverOptions = {
-		command: "pyre",
+	const serverOptions = {
+		command: pyrePath,
 		args: ["persistent"]
 	};
 
-	let clientOptions: LanguageClientOptions = {
+	const clientOptions: LanguageClientOptions = {
 		documentSelector: [{scheme: 'file', language: 'python'}],
 		synchronize: {
 			// Notify the server about file changes to '.clientrc files contain in the workspace
@@ -54,12 +80,51 @@ export async function activate(_: vscode.ExtensionContext) {
 	)
 
 	languageClient.registerProposedFeatures();
-	languageClient.onReady().then(() => {
-		Configuration.initialize();
+
+	const configListener = languageClient.onReady().then(() => {
+		return vscode.workspace.onDidChangeConfiguration(() => {
+			languageClient.sendNotification(DidChangeConfigurationNotification.type, { settings: null });
+		});
 	});
+
 	languageClient.start();
+
+	return {languageClient, configListener};
+}
+
+async function findPyreCommand(envPath: EnvironmentPath) : Promise<string | undefined> {
+
+	if (envPath.id === 'DEFAULT_PYTHON') {
+		outputChannel.appendLine(`Using the default python environment`);
+		return 'pyre';
+	}
+
+	const path = envPath.path;
+	const stat = statSync(path)
+
+	const pyrePath = stat.isFile()
+		? join(dirname(envPath.path), 'pyre')
+		: stat.isDirectory()
+			? join(path, 'bin', 'pyre')
+			: undefined;
+
+	if (pyrePath && existsSync(pyrePath) && statSync(pyrePath).isFile()) {
+		outputChannel.appendLine(`Using pyre path: ${pyrePath} from python environment: ${envPath.id} at ${envPath.path}`);
+		return pyrePath;
+	}
+
+	const pyreFromPathEnvVariable = await which('pyre', { nothrow: true });
+	if (pyreFromPathEnvVariable != null) {
+		outputChannel.appendLine(`Using pyre path: ${pyreFromPathEnvVariable} from PATH`);
+		return pyreFromPathEnvVariable;
+	}
+
+	outputChannel.appendLine(`Could not find pyre path from python environment: ${envPath.id} at ${envPath.path}`);
+	return undefined;
 }
 
 export function deactivate() {
-	Configuration.dispose();
+	state?.languageClient.stop();
+	state?.configListener.then((listener) => listener.dispose());
+	envListener?.dispose();
 }

tools/ide_plugins/vscode/tsconfig.json

@@ -12,7 +12,8 @@
         "noImplicitAny": false,
         "noImplicitReturns": true,
         "noUnusedLocals": true,
-        "noUnusedParameters": true
+        "noUnusedParameters": true,
+        "esModuleInterop": true
     },
     "exclude": [
         "node_modules",