balena-cli/lib/utils/helpers.ts

/*
Copyright 2016-2020 Balena

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import { InitializeEmitter, OperationState } from 'balena-device-init';
import * as BalenaSdk from 'balena-sdk';
import Bluebird = require('bluebird');
import _ = require('lodash');
import os = require('os');
import * as ShellEscape from 'shell-escape';

import { ExpectedError } from '../errors';
import { getBalenaSdk, getChalk, getVisuals } from './lazy';

export function getGroupDefaults(group: {
	options: Array<{ name: string; default?: string }>;
}): { [name: string]: string | number | undefined } {
	return _.chain(group)
		.get('options')
		.map(question => [question.name, question.default])
		.fromPairs()
		.value();
}

export function stateToString(state: OperationState) {
	const percentage = _.padStart(`${state.percentage}`, 3, '0');
	const chalk = getChalk();
	const result = `${chalk.blue(percentage + '%')} ${chalk.cyan(
		state.operation.command,
	)}`;

	switch (state.operation.command) {
		case 'copy':
			return `${result} ${state.operation.from.path} -> ${state.operation.to.path}`;
		case 'replace':
			return `${result} ${state.operation.file.path}, ${state.operation.copy} -> ${state.operation.replace}`;
		case 'run-script':
			return `${result} ${state.operation.script}`;
		default:
			throw new Error(`Unsupported operation: ${state.operation.command}`);
	}
}

/**
 * Execute a child process with admin / superuser privileges, prompting the user for
 * elevation as needed, and taking care of shell-escaping arguments in a suitable way
 * for Windows and Linux/Mac.
 *
 * @param command Unescaped array of command and args to be executed. If isCLIcmd is
 * true, the command should not include the 'node' or 'balena' components, for example:
 * ['internal', 'osinit', ...]. This function will add argv[0] and argv[1] as needed
 * (taking process.pkg into account -- CLI standalone zip package), and will also
 * shell-escape the arguments as needed, taking into account the differences between
 * bash/sh and the Windows cmd.exe in relation to escape characters.
 * @param msg Optional message for the user, before the password prompt
 * @param stderr Optional stream to which stderr should be piped
 * @param isCLIcmd (default: true) Whether the command array is a balena CLI command
 * (e.g. ['internal', 'osinit', ...]), in which case process.argv[0] and argv[1] are
 * added as necessary, depending on whether the CLI is running as a standalone zip
 * package (with Node built in).
 */
export async function sudo(
	command: string[],
	{
		stderr,
		msg,
		isCLIcmd,
	}: { stderr?: NodeJS.WritableStream; msg?: string; isCLIcmd?: boolean } = {},
) {
	const { executeWithPrivileges } = await import('./sudo');

	if (os.platform() !== 'win32') {
		console.log(
			msg ||
				'Admin privileges required: you may be asked for your computer password to continue.',
		);
	}
	if (isCLIcmd == null) {
		isCLIcmd = true;
	}
	await executeWithPrivileges(command, stderr, isCLIcmd);
}

export function runCommand(command: string): Bluebird<void> {
	const capitano = require('capitano');
	return Bluebird.fromCallback(resolver => capitano.run(command, resolver));
}

export async function getManifest(
	image: string,
	deviceType: string,
): Promise<BalenaSdk.DeviceType> {
	const init = await import('balena-device-init');
	const manifest = await init.getImageManifest(image);
	if (manifest != null) {
		return manifest;
	}
	return getBalenaSdk().models.device.getManifestBySlug(deviceType);
}

export const areDeviceTypesCompatible = (
	deviceTypeA: BalenaSdk.DeviceType,
	deviceTypeB: BalenaSdk.DeviceType,
) =>
	deviceTypeA.arch === deviceTypeB.arch &&
	!!deviceTypeA.isDependent === !!deviceTypeB.isDependent;

export async function osProgressHandler(step: InitializeEmitter) {
	step.on('stdout', process.stdout.write.bind(process.stdout));
	step.on('stderr', process.stderr.write.bind(process.stderr));

	step.on('state', function(state) {
		if (state.operation.command === 'burn') {
			return;
		}
		console.log(exports.stateToString(state));
	});

	const visuals = getVisuals();
	const progressBars = {
		write: new visuals.Progress('Writing Device OS'),
		check: new visuals.Progress('Validating Device OS'),
	};

	step.on('burn', state => progressBars[state.type].update(state));

	await new Promise((resolve, reject) => {
		step.on('error', reject);
		step.on('end', resolve);
	});
}

export function getArchAndDeviceType(
	applicationName: string,
): Bluebird<{ arch: string; device_type: string }> {
	return Bluebird.join(
		getApplication(applicationName),
		getBalenaSdk().models.config.getDeviceTypes(),
		function(app, deviceTypes) {
			const config = _.find<BalenaSdk.DeviceType>(deviceTypes, {
				slug: app.device_type,
			});

			if (!config) {
				throw new Error('Could not read application information!');
			}

			return { device_type: app.device_type, arch: config.arch };
		},
	);
}

export function getApplication(applicationName: string) {
	// Check for an app of the form `user/application`, and send
	// that off to a special handler (before importing any modules)
	const match = applicationName.split('/');

	const extraOptions: BalenaSdk.PineOptionsFor<BalenaSdk.Application> = {
		$expand: {
			application_type: {
				$select: ['name', 'slug', 'supports_multicontainer', 'is_legacy'],
			},
		},
	};

	const balena = getBalenaSdk();
	if (match.length > 1) {
		return balena.models.application.getAppByOwner(
			match[1],
			match[0],
			extraOptions,
		);
	}

	return balena.models.application.get(applicationName, extraOptions);
}

/**
 * Choose between 'cmd.exe' and '/bin/sh' for running the given command string,
 * depending on the value of `os.platform()`.
 * When writing new code, consider whether it would be possible to avoid using a
 * shell at all, using the which() function in this module to obtain a program's
 * full path, executing the program directly and passing the arguments as an
 * array instead of a long string. Avoiding a shell has several benefits:
 *   - Avoids the need to shell-escape arguments, especially nested commands.
 *   - Bypasses the incompatibilities between cmd.exe and /bin/sh.
 *   - Reduces the security risks of lax input validation.
 * Code example avoiding a shell:
 *    const program = await which('ssh');
 *    const args = ['root@192.168.1.1', 'cat /etc/os-release'];
 *    const child = spawn(program, args);
 */
export function getSubShellCommand(command: string) {
	if (os.platform() === 'win32') {
		return {
			program: 'cmd.exe',
			args: ['/s', '/c', command],
		};
	} else {
		return {
			program: '/bin/sh',
			args: ['-c', command],
		};
	}
}

/**
 * Call `func`, and if func() throws an error or returns a promise that
 * eventually rejects, retry it `times` many times, each time printing a
 * log message including the given `label` and the error that led to
 * retrying. Wait delayMs before the first retry, multiplying the wait
 * by backoffScaler for each further attempt.
 * @param func: The function to call and, if needed, retry calling
 * @param times: How many times to retry calling func()
 * @param label: Label to include in the retry log message
 * @param delayMs: How long to wait before the first retry
 * @param backoffScaler: Multiplier to previous wait time
 * @param count: Used "internally" for the recursive calls
 */
export function retry<T>(
	func: () => T,
	times: number,
	label: string,
	delayMs = 1000,
	backoffScaler = 2,
	count = 0,
): Bluebird<T> {
	let promise = Bluebird.try(func);
	if (count < times) {
		promise = promise.catch((err: Error) => {
			const delay = backoffScaler ** count * delayMs;
			console.log(
				`Retrying "${label}" after ${(delay / 1000).toFixed(2)}s (${count +
					1} of ${times}) due to: ${err}`,
			);
			return Bluebird.delay(delay).then(() =>
				retry(func, times, label, delayMs, backoffScaler, count + 1),
			);
		});
	}
	return promise;
}

/**
 * Return a compare(a, b) function suitable for use as the argument for the
 * sort() method of an array. That function will use the given manuallySortedArray
 * as "sorting guidance":
 *   - If both a and b are found in the manuallySortedArray, the returned
 *     compare(a, b) function will follow that ordering.
 *   - If neither a nor b are found in the manuallySortedArray, the returned
 *     compare(a, b) function will compare a and b using the standard '<' and
 *     '>' Javascript operators.
 *   - If only a or only b are found in the manuallySortedArray, the returned
 *     compare(a, b) function will treat the element that was found as being
 *     "smaller than" the not-found element (i.e. found elements appear before
 *     not-found elements in sorted order).
 *
 * The equalityFunc(a, x) argument is a function used to compare the items
 * being sorted against the items in the manuallySortedArray. For example, if
 * equalityFunc was (a, x) => a.startsWith(x), where a is an item being sorted
 * and x is an item in the manuallySortedArray, then the manuallySortedArray
 * could contain prefix substrings to guide the sorting.
 *
 * @param manuallySortedArray A pre-sorted array to guide the sorting
 * @param equalityFunc An optional function used to compare the items being
 *   sorted against items in manuallySortedArray. It should return true if
 *   the two items compare equal, otherwise false. The arguments are the
 *   same as provided by the standard Javascript array.findIndex() method.
 */
export function getManualSortCompareFunction<T, U = T>(
	manuallySortedArray: U[],
	equalityFunc: (a: T, x: U, index: number, array: U[]) => boolean,
): (a: T, b: T) => number {
	return function(a: T, b: T): number {
		const indexA = manuallySortedArray.findIndex((x, index, array) =>
			equalityFunc(a, x, index, array),
		);
		const indexB = manuallySortedArray.findIndex((x, index, array) =>
			equalityFunc(b, x, index, array),
		);
		if (indexA >= 0 && indexB >= 0) {
			return indexA - indexB;
		} else if (indexA < 0 && indexB < 0) {
			return a < b ? -1 : a > b ? 1 : 0;
		} else {
			return indexA < 0 ? 1 : -1;
		}
	};
}

/**
 * Decide whether the current shell (that executed the CLI process) is a Windows
 * 'cmd.exe' shell, including PowerShell, by checking a few environment
 * variables.
 */
export function isWindowsComExeShell() {
	return (
		// neither bash nor sh (e.g. not MSYS, MSYS2, Cygwin, WSL)
		process.env.SHELL == null &&
		// Windows cmd.exe or PowerShell
		process.env.ComSpec != null &&
		process.env.ComSpec.endsWith('cmd.exe')
	);
}

/**
 * Shell argument escaping compatible with sh, bash and Windows cmd.exe.
 * @param arg Arguments to be escaped
 * @param detectShell Whether to use the SHELL and ComSpec environment
 * variables to determine the shell type (sh / bash / cmd.exe). This may be
 * useful to detect MSYS / MSYS2, which use bash on Windows. However, if the
 * purpose is to use child_process.spawn(..., {shell: true}) and related
 * functions, set this to false because child_process.spawn() always uses
 * env.ComSpec (cmd.exe) on Windows, even when running on MSYS / MSYS2.
 */
export function shellEscape(args: string[], detectShell = false): string[] {
	const isCmdExe = detectShell
		? isWindowsComExeShell()
		: process.platform === 'win32';
	if (isCmdExe) {
		return args.map(v => windowsCmdExeEscapeArg(v));
	} else {
		const shellEscapeFunc: typeof ShellEscape = require('shell-escape');
		return args.map(v => shellEscapeFunc([v]));
	}
}

/**
 * Escape a string argument to be passed through the Windows cmd.exe shell.
 * cmd.exe escaping has some peculiarities, like using the caret character
 * instead of a backslash for reserved / metacharacters. Reference:
 * https://blogs.msdn.microsoft.com/twistylittlepassagesallalike/2011/04/23/everyone-quotes-command-line-arguments-the-wrong-way/
 */
function windowsCmdExeEscapeArg(arg: string): string {
	// if it is already double quoted, remove the double quotes
	if (arg.length > 1 && arg.startsWith('"') && arg.endsWith('"')) {
		arg = arg.slice(1, -1);
	}
	// escape cmd.exe metacharacters with the '^' (caret) character
	arg = arg.replace(/[()%!^<>&|]/g, '^$&');
	// duplicate internal double quotes, and double quote overall
	return `"${arg.replace(/["]/g, '""')}"`;
}

/**
 * Workaround a window system bug which causes multiple rapid DNS lookups
 * to fail for mDNS.
 *
 * It introduces a simple pause, and should be used between operations that
 * trigger mDNS resolutions.
 *
 * Windows bug: https://support.microsoft.com/en-gb/help/4057932/getaddrinfo-failed-with-wsahost-not-found-11001-error
 */
export async function workaroundWindowsDnsIssue(ipOrHostname: string) {
	// 300ms seemed to be the smallest delay that worked reliably but may
	// vary between systems.
	const delay = 500;
	if (process.platform === 'win32' && ipOrHostname.includes('.local')) {
		await new Promise(r => setTimeout(r, delay));
	}
}

/**
 * Error handling wrapper around the npm `which` package:
 * "Like the unix which utility. Finds the first instance of a specified
 * executable in the PATH environment variable. Does not cache the results,
 * so hash -r is not needed when the PATH changes."
 *
 * @param program Basename of a program, for example 'ssh'
 * @param rejectOnMissing If the program cannot be found, reject the promise
 * with an ExpectedError instead of fulfilling it with an empty string.
 * @returns The program's full path, e.g. 'C:\WINDOWS\System32\OpenSSH\ssh.EXE'
 */
export async function which(
	program: string,
	rejectOnMissing = true,
): Promise<string> {
	const whichMod = await import('which');
	let programPath: string;
	try {
		programPath = await whichMod(program);
	} catch (err) {
		if (err.code === 'ENOENT') {
			if (rejectOnMissing) {
				throw new ExpectedError(
					`'${program}' program not found. Is it installed?`,
				);
			} else {
				return '';
			}
		}
		throw err;
	}
	return programPath;
}

export interface ProxyConfig {
	host: string;
	port: string;
	username?: string;
	password?: string;
	proxyAuth?: string;
}

/**
 * Check whether a proxy has been configured (whether global-tunnel-ng or
 * global-agent) and if so, return a ProxyConfig object.
 */
export function getProxyConfig(): ProxyConfig | undefined {
	const tunnelNgConfig: any = (global as any).PROXY_CONFIG;
	// global-tunnel-ng
	if (tunnelNgConfig) {
		let username: string | undefined;
		let password: string | undefined;
		const proxyAuth: string = tunnelNgConfig.proxyAuth;
		if (proxyAuth) {
			const i = proxyAuth.lastIndexOf(':');
			if (i > 0) {
				username = proxyAuth.substring(0, i);
				password = proxyAuth.substring(i + 1);
			}
		}
		return {
			host: tunnelNgConfig.host,
			port: `${tunnelNgConfig.port}`,
			username,
			password,
			proxyAuth: tunnelNgConfig.proxyAuth,
		};
		// global-agent, or no proxy config
	} else {
		const proxyUrl = process.env.HTTPS_PROXY || process.env.HTTP_PROXY;
		if (proxyUrl) {
			const { URL } = require('url') as typeof import('url');
			let url: URL;
			try {
				url = new URL(proxyUrl);
			} catch (_e) {
				return;
			}
			return {
				host: url.hostname,
				port: url.port,
				username: url.username,
				password: url.password,
				proxyAuth:
					url.username && url.password
						? `${url.username}:${url.password}`
						: undefined,
			};
		}
	}
}