balena-cli/lib/utils/helpers.ts

/*
Copyright 2016-2019 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 BalenaSdk = require('balena-sdk');
import Bluebird = require('bluebird');
import chalk from 'chalk';
import _ = require('lodash');
import os = require('os');
import visuals = require('resin-cli-visuals');
import * as ShellEscape from 'shell-escape';

import { InitializeEmitter, OperationState } from 'balena-device-init';

const balena = BalenaSdk.fromSharedOptions();

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(`${state.percentage}`, 3, '0');
	const result = `${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 balena.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 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),
		balena.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'],
			},
		},
	};

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

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

// A function to reliably execute a command
// in all supported operating systems, including
// different Windows environments like `cmd.exe`
// and `Cygwin`.
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;
		}
	};
}

/**
 * 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[] {
	let isWindowsCmdExeShell: boolean;
	if (detectShell) {
		isWindowsCmdExeShell =
			// neither bash nor sh (e.g. not MSYS, MSYS2, WSL)
			process.env.SHELL == null &&
			// Windows cmd.exe or PowerShell
			process.env.ComSpec != null &&
			process.env.ComSpec.endsWith('cmd.exe');
	} else {
		isWindowsCmdExeShell = process.platform === 'win32';
	}
	if (isWindowsCmdExeShell) {
		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));
	}
}