[vscode] Use activated venv

tools/ide_plugins/vscode/.gitignore

@@ -0,0 +1 @@
+out/**

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"
@@ -31,10 +31,11 @@
   "devDependencies": {
     "@types/mocha": "^2.2.44",
     "@types/node": "^8.0.53",
+    "@vscode/python-extension": "^1.0.5",
     "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

@@ -11,9 +11,14 @@
 
 import * as vscode from 'vscode';
 import { LanguageClient, LanguageClientOptions, DidChangeConfigurationNotification } from 'vscode-languageclient';
+import { EnvironmentPath, PythonExtension } from '@vscode/python-extension'
+import { basename, dirname, join } from 'path';
+import { existsSync, statSync } from 'fs';
 
 let languageClient: LanguageClient;
 
+let outputChannel = vscode.window.createOutputChannel("pyre");
+
 namespace Configuration {
 
 	let configurationListener: vscode.Disposable;
@@ -33,12 +38,42 @@ namespace Configuration {
 
 export async function activate(_: vscode.ExtensionContext) {
 
-	let serverOptions = {
-		command: "pyre",
+	const pythonExtension = vscode.extensions.getExtension<PythonExtension>('ms-python.python');
+
+	if (!pythonExtension) {
+		outputChannel.appendLine("Python extension not found. Will use the default console environment.");
+		createLanguageClient('pyre');
+		return;
+	}
+
+	const activatedEnvPath = pythonExtension.exports.environments.getActiveEnvironmentPath();
+	const pyrePath = inferPyreCommand(activatedEnvPath);
+
+	let languageClient: LanguageClient | undefined;
+
+	if (pyrePath) {
+		languageClient = createLanguageClient(pyrePath);
+	}
+
+	pythonExtension.exports.environments.onDidChangeActiveEnvironmentPath((e) => {
+		languageClient?.stop();
+		languageClient = undefined;
+
+		const pyrePath = inferPyreCommand(e);
+		if (pyrePath) {
+			languageClient = createLanguageClient(pyrePath);
+		}
+	});
+}
+
+function createLanguageClient(pyrePath: string) : LanguageClient {
+
+	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
@@ -58,6 +93,29 @@ export async function activate(_: vscode.ExtensionContext) {
 		Configuration.initialize();
 	});
 	languageClient.start();
+
+	return languageClient;
+}
+
+function inferPyreCommand(envPath: EnvironmentPath) : string | undefined {
+	const path = envPath.path;
+	const stat = statSync(path)
+
+	const pyrePath = stat.isFile() && basename(path) === 'python'
+		? 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}`);
+	} else if (pyrePath) {
+		outputChannel.appendLine(`Environment: ${envPath.id} at ${envPath.path} does not contain a pyre executable at ${pyrePath}`);
+	} else {
+		outputChannel.appendLine(`Could not infer pyre path from python environment: ${envPath.id} at ${envPath.path}`);
+	}
+
+	return pyrePath;
 }
 
 export function deactivate() {