Find Windows executable (#284)

Author: chrmarti

common/src/dev-container-cli.ts

@@ -4,6 +4,7 @@ import path from 'path';
 import {env} from 'process';
 import {promisify} from 'util';
 import {ExecFunction} from './exec';
+import {findWindowsExecutable} from './windows';
 
 const cliVersion = "0"; // Use 'latest' to get latest CLI version, or pin to specific version e.g. '0.14.1' if required
 
@@ -27,7 +28,8 @@ function getSpecCliInfo() {
 
 async function isCliInstalled(exec: ExecFunction): Promise<boolean> {
   try {
-    const {exitCode} = await exec(getSpecCliInfo().command, ['--help'], {
+    const command = await findWindowsExecutable(getSpecCliInfo().command);
+    const {exitCode} = await exec(command, ['--help'], {
       silent: true,
     });
     return exitCode === 0;
@@ -121,7 +123,7 @@ async function runSpecCliJsonCommand<T>(options: {
     err: data => options.log(data),
     env: options.env ? {...process.env, ...options.env} : process.env,
   };
-  const command = getSpecCliInfo().command;
+  const command = await findWindowsExecutable(getSpecCliInfo().command);
   console.log(`About to run ${command} ${options.args.join(' ')}`); // TODO - take an output arg to allow GH to use core.info
   await spawn(command, options.args, spawnOptions);
 
@@ -138,7 +140,7 @@ async function runSpecCliNonJsonCommand(options: {
     err: data => options.log(data),
     env: options.env ? {...process.env, ...options.env} : process.env,
   };
-  const command = getSpecCliInfo().command;
+  const command = await findWindowsExecutable(getSpecCliInfo().command);
   console.log(`About to run ${command} ${options.args.join(' ')}`); // TODO - take an output arg to allow GH to use core.info
   const result = await spawn(command, options.args, spawnOptions);
   return result.code

common/src/windows.ts

@@ -0,0 +1,86 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as path from 'path';
+import * as fs from 'fs';
+
+// From Dev Containers CLI
+export async function findWindowsExecutable(command: string): Promise<string> {
+	if (process.platform !== 'win32') {
+		return command;
+	}
+
+	// If we have an absolute path then we take it.
+	if (path.isAbsolute(command)) {
+		return await findWindowsExecutableWithExtension(command) || command;
+	}
+	const cwd = process.cwd();
+	if (/[/\\]/.test(command)) {
+		// We have a directory and the directory is relative (see above). Make the path absolute
+		// to the current working directory.
+		const fullPath = path.join(cwd, command);
+		return await findWindowsExecutableWithExtension(fullPath) || fullPath;
+	}
+	let pathValue: string | undefined = undefined;
+	let paths: string[] | undefined = undefined;
+	const env = process.env;
+	// Path can be named in many different ways and for the execution it doesn't matter
+	for (let key of Object.keys(env)) {
+		if (key.toLowerCase() === 'path') {
+			const value = env[key];
+			if (typeof value === 'string') {
+				pathValue = value;
+				paths = value.split(path.delimiter)
+					.filter(Boolean);
+			}
+			break;
+		}
+	}
+	// No PATH environment. Bail out.
+	if (paths === void 0 || paths.length === 0) {
+		const err = new Error(`No PATH to look up executable '${command}'.`);
+		(err as any).code = 'ENOENT';
+		throw err;
+	}
+	// We have a simple file name. We get the path variable from the env
+	// and try to find the executable on the path.
+	for (let pathEntry of paths) {
+		// The path entry is absolute.
+		let fullPath: string;
+		if (path.isAbsolute(pathEntry)) {
+			fullPath = path.join(pathEntry, command);
+		} else {
+			fullPath = path.join(cwd, pathEntry, command);
+		}
+		const withExtension = await findWindowsExecutableWithExtension(fullPath);
+		if (withExtension) {
+			return withExtension;
+		}
+	}
+	// Not found in PATH. Bail out.
+	const err = new Error(`Exectuable '${command}' not found on PATH '${pathValue}'.`);
+	(err as any).code = 'ENOENT';
+	throw err;
+}
+
+const pathext = process.env.PATHEXT;
+const executableExtensions = pathext ? pathext.toLowerCase().split(';') : ['.com', '.exe', '.bat', '.cmd'];
+
+async function findWindowsExecutableWithExtension(fullPath: string) {
+	if (executableExtensions.indexOf(path.extname(fullPath)) !== -1) {
+		return await isFile(fullPath) ? fullPath : undefined;
+	}
+	for (const ext of executableExtensions) {
+		const withExtension = fullPath + ext;
+		if (await isFile(withExtension)) {
+			return withExtension;
+		}
+	}
+	return undefined;
+}
+
+function isFile(filepath: string): Promise<boolean> {
+	return new Promise(r => fs.stat(filepath, (err, stat) => r(!err && stat.isFile())));
+}