micro.js

#!/usr/bin/env node

// Native
const http = require('http');
const path = require('path');
const {existsSync} = require('fs');

// Packages
const arg = require('arg');

// Utilities
const serve = require('../lib');
const handle = require('../lib/handler');
const {version} = require('../package');
const logError = require('../lib/error');
const parseEndpoint = require('../lib/parse-endpoint.js');

// Check if the user defined any options
const args = arg({
	'--listen': [parseEndpoint],
	'-l': '--listen',

	'--help': Boolean,

	'--version': Boolean,
	'-v': '--version',

	// Deprecated options
	'--port': Number,
	'-p': '--port',
	'--host': String,
	'-h': '--host',
	'--unix-socket': String,
	'-s': '--unix-socket'
});

// When `-h` or `--help` are used, print out
// the usage information
if (args['--help']) {
	console.error(`
  micro - Asynchronous HTTP microservices

  USAGE

      $ micro --help
      $ micro --version
      $ micro [-l listen_uri [-l ...]] [entry_point.js]

      By default micro will listen on 0.0.0.0:3000 and will look first
      for the "main" property in package.json and subsequently for index.js
      as the default entry_point.

      Specifying a single --listen argument will overwrite the default, not supplement it.

  OPTIONS

      --help                              shows this help message

      -v, --version                       displays the current version of micro

      -l, --listen listen_uri             specify a URI endpoint on which to listen (see below) -
                                          more than one may be specified to listen in multiple places

  ENDPOINTS

      Listen endpoints (specified by the --listen or -l options above) instruct micro
      to listen on one or more interfaces/ports, UNIX domain sockets, or Windows named pipes.

      For TCP (traditional host/port) endpoints:

          $ micro -l tcp://hostname:1234

      For UNIX domain socket endpoints:

          $ micro -l unix:/path/to/socket.sock

      For Windows named pipe endpoints:

          $ micro -l pipe:\\\\.\\pipe\\PipeName
`);
	process.exit(2);
}

// Print out the package's version when
// `--version` or `-v` are used
if (args['--version']) {
	console.log(version);
	process.exit();
}

if ((args['--port'] || args['--host']) && args['--unix-socket']) {
	logError(
		`Both host/port and socket provided. You can only use one.`,
		'invalid-port-socket'
	);
	process.exit(1);
}

let deprecatedEndpoint = null;

args['--listen'] = args['--listen'] || [];

if (args['--port']) {
	const {isNaN} = Number;
	const port = Number(args['--port']);
	if (isNaN(port) || (!isNaN(port) && (port < 1 || port >= Math.pow(2, 16)))) {
		logError(
			`Port option must be a number. Supplied: ${args['--port']}`,
			'invalid-server-port'
		);
		process.exit(1);
	}

	deprecatedEndpoint = [args['--port']];
}

if (args['--host']) {
	deprecatedEndpoint = deprecatedEndpoint || [];
	deprecatedEndpoint.push(args['--host']);
}

if (deprecatedEndpoint) {
	args['--listen'].push(deprecatedEndpoint);
}

if (args['--unix-socket']) {
	if (typeof args['--unix-socket'] === 'boolean') {
		logError(
			`Socket must be a string. A boolean was provided.`,
			'invalid-socket'
		);
	}
	args['--listen'].push(args['--unix-socket']);
}

if (args['--port'] || args['--host'] || args['--unix-socket']) {
	logError(
		'--port, --host, and --unix-socket are deprecated - see --help for information on the --listen flag',
		'deprecated-endpoint-flags'
	);
}

if (args['--listen'].length === 0) {
	// default endpoint
	args['--listen'].push([3000]);
}

let file = args._[0];

if (!file) {
	try {
		const packageJson = require(path.resolve(process.cwd(), 'package.json'));
		file = packageJson.main || 'index.js';
	} catch (err) {
		if (err.code !== 'MODULE_NOT_FOUND') {
			logError(
				`Could not read \`package.json\`: ${err.message}`,
				'invalid-package-json'
			);
			process.exit(1);
		}
	}
}

if (!file) {
	logError('Please supply a file!', 'path-missing');
	process.exit(1);
}

if (file[0] !== '/') {
	file = path.resolve(process.cwd(), file);
}

if (!existsSync(file)) {
	logError(
		`The file or directory "${path.basename(file)}" doesn't exist!`,
		'path-not-existent'
	);
	process.exit(1);
}

function registerShutdown(fn) {
	let run = false;

	const wrapper = () => {
		if (!run) {
			run = true;
			fn();
		}
	};

	process.on('SIGINT', wrapper);
	process.on('SIGTERM', wrapper);
	process.on('exit', wrapper);
}

function startEndpoint(module, endpoint) {
	const server = new http.Server(serve(module));

	server.on('error', err => {
		console.error('micro:', err.stack);
		process.exit(1);
	});

	server.listen(...endpoint, () => {
		const details = server.address();

		registerShutdown(() => server.close());

		// `micro` is designed to run only in production, so
		// this message is perfectly for prod
		if (typeof details === 'string') {
			console.log(`micro: Accepting connections on ${details}`);
		} else if (typeof details === 'object' && details.port) {
			console.log(`micro: Accepting connections on port ${details.port}`);
		} else {
			console.log('micro: Accepting connections');
		}
	});
}

async function start() {
	const loadedModule = await handle(file);

	for (const endpoint of args['--listen']) {
		startEndpoint(loadedModule, endpoint);
	}

	registerShutdown(() => console.log('micro: Gracefully shutting down. Please wait...'));
}

start();