// @ts-check const os = require('os'); const throng = require('throng'); const dotenv = require('dotenv'); const express = require('express'); const http = require('http'); const redis = require('redis'); const pg = require('pg'); const log = require('npmlog'); const url = require('url'); const uuid = require('uuid'); const fs = require('fs'); const WebSocket = require('ws'); const env = process.env.NODE_ENV || 'development'; const alwaysRequireAuth = process.env.LIMITED_FEDERATION_MODE === 'true' || process.env.WHITELIST_MODE === 'true' || process.env.AUTHORIZED_FETCH === 'true'; dotenv.config({ path: env === 'production' ? '.env.production' : '.env', }); log.level = process.env.LOG_LEVEL || 'verbose'; /** * @param {string} dbUrl * @return {Object.} */ const dbUrlToConfig = (dbUrl) => { if (!dbUrl) { return {}; } const params = url.parse(dbUrl, true); const config = {}; if (params.auth) { [config.user, config.password] = params.auth.split(':'); } if (params.hostname) { config.host = params.hostname; } if (params.port) { config.port = params.port; } if (params.pathname) { config.database = params.pathname.split('/')[1]; } const ssl = params.query && params.query.ssl; if (ssl && ssl === 'true' || ssl === '1') { config.ssl = true; } return config; }; /** * @param {Object.} defaultConfig * @param {string} redisUrl */ const redisUrlToClient = async (defaultConfig, redisUrl) => { const config = defaultConfig; let client; if (!redisUrl) { client = redis.createClient(config); } else if (redisUrl.startsWith('unix://')) { client = redis.createClient(Object.assign(config, { socket: { path: redisUrl.slice(7), }, })); } else { client = redis.createClient(Object.assign(config, { url: redisUrl, })); } client.on('error', (err) => log.error('Redis Client Error!', err)); await client.connect(); return client; }; const numWorkers = +process.env.STREAMING_CLUSTER_NUM || (env === 'development' ? 1 : Math.max(os.cpus().length - 1, 1)); /** * @param {string} json * @return {Object.|null} */ const parseJSON = (json) => { try { return JSON.parse(json); } catch (err) { log.error(err); return null; } }; const startMaster = () => { if (!process.env.SOCKET && process.env.PORT && isNaN(+process.env.PORT)) { log.warn('UNIX domain socket is now supported by using SOCKET. Please migrate from PORT hack.'); } log.warn(`Starting streaming API server master with ${numWorkers} workers`); }; const startWorker = async (workerId) => { log.warn(`Starting worker ${workerId}`); const pgConfigs = { development: { user: process.env.DB_USER || pg.defaults.user, password: process.env.DB_PASS || pg.defaults.password, database: process.env.DB_NAME || 'mastodon_development', host: process.env.DB_HOST || pg.defaults.host, port: process.env.DB_PORT || pg.defaults.port, max: 10, }, production: { user: process.env.DB_USER || 'mastodon', password: process.env.DB_PASS || '', database: process.env.DB_NAME || 'mastodon_production', host: process.env.DB_HOST || 'localhost', port: process.env.DB_PORT || 5432, max: 10, }, }; if (!!process.env.DB_SSLMODE && process.env.DB_SSLMODE !== 'disable') { pgConfigs.development.ssl = true; pgConfigs.production.ssl = true; } const app = express(); app.set('trusted proxy', process.env.TRUSTED_PROXY_IP || 'loopback,uniquelocal'); const pgPool = new pg.Pool(Object.assign(pgConfigs[env], dbUrlToConfig(process.env.DATABASE_URL))); const server = http.createServer(app); const redisNamespace = process.env.REDIS_NAMESPACE || null; const redisParams = { socket: { host: process.env.REDIS_HOST || '127.0.0.1', port: process.env.REDIS_PORT || 6379, }, database: process.env.REDIS_DB || 0, password: process.env.REDIS_PASSWORD || undefined, }; if (redisNamespace) { redisParams.namespace = redisNamespace; } const redisPrefix = redisNamespace ? `${redisNamespace}:` : ''; const redisSubscribeClient = await redisUrlToClient(redisParams, process.env.REDIS_URL); const redisClient = await redisUrlToClient(redisParams, process.env.REDIS_URL); /** * @param {string[]} channels * @return {function(): void} */ const subscriptionHeartbeat = channels => { const interval = 6 * 60; const tellSubscribed = () => { channels.forEach(channel => redisClient.set(`${redisPrefix}subscribed:${channel}`, '1', 'EX', interval * 3)); }; tellSubscribed(); const heartbeat = setInterval(tellSubscribed, interval * 1000); return () => { clearInterval(heartbeat); }; }; /** * @param {string} channel * @param {function(string): void} callback */ const subscribe = (channel, callback) => { log.silly(`Adding listener for ${channel}`); redisSubscribeClient.subscribe(channel, callback); }; /** * @param {string} channel */ const unsubscribe = (channel) => { redisSubscribeClient.unsubscribe(channel); }; const FALSE_VALUES = [ false, 0, '0', 'f', 'F', 'false', 'FALSE', 'off', 'OFF', ]; /** * @param {any} value * @return {boolean} */ const isTruthy = value => value && !FALSE_VALUES.includes(value); /** * @param {any} req * @param {any} res * @param {function(Error=): void} */ const allowCrossDomain = (req, res, next) => { res.header('Access-Control-Allow-Origin', '*'); res.header('Access-Control-Allow-Headers', 'Authorization, Accept, Cache-Control'); res.header('Access-Control-Allow-Methods', 'GET, OPTIONS'); next(); }; /** * @param {any} req * @param {any} res * @param {function(Error=): void} */ const setRequestId = (req, res, next) => { req.requestId = uuid.v4(); res.header('X-Request-Id', req.requestId); next(); }; /** * @param {any} req * @param {any} res * @param {function(Error=): void} */ const setRemoteAddress = (req, res, next) => { req.remoteAddress = req.connection.remoteAddress; next(); }; /** * @param {any} req * @param {string[]} necessaryScopes * @return {boolean} */ const isInScope = (req, necessaryScopes) => req.scopes.some(scope => necessaryScopes.includes(scope)); /** * @param {string} token * @param {any} req * @return {Promise.} */ const accountFromToken = (token, req) => new Promise((resolve, reject) => { pgPool.connect((err, client, done) => { if (err) { reject(err); return; } client.query('SELECT oauth_access_tokens.id, oauth_access_tokens.resource_owner_id, users.account_id, users.chosen_languages, oauth_access_tokens.scopes, devices.device_id FROM oauth_access_tokens INNER JOIN users ON oauth_access_tokens.resource_owner_id = users.id LEFT OUTER JOIN devices ON oauth_access_tokens.id = devices.access_token_id WHERE oauth_access_tokens.token = $1 AND oauth_access_tokens.revoked_at IS NULL LIMIT 1', [token], (err, result) => { done(); if (err) { reject(err); return; } if (result.rows.length === 0) { err = new Error('Invalid access token'); err.status = 401; reject(err); return; } req.accessTokenId = result.rows[0].id; req.scopes = result.rows[0].scopes.split(' '); req.accountId = result.rows[0].account_id; req.chosenLanguages = result.rows[0].chosen_languages; req.deviceId = result.rows[0].device_id; resolve(); }); }); }); /** * @param {any} req * @param {boolean=} required * @return {Promise.} */ const accountFromRequest = (req, required = true) => new Promise((resolve, reject) => { const authorization = req.headers.authorization; const location = url.parse(req.url, true); const accessToken = location.query.access_token || req.headers['sec-websocket-protocol']; if (!authorization && !accessToken) { if (required) { const err = new Error('Missing access token'); err.status = 401; reject(err); return; } else { resolve(); return; } } const token = authorization ? authorization.replace(/^Bearer /, '') : accessToken; resolve(accountFromToken(token, req)); }); /** * @param {any} req * @return {string} */ const channelNameFromPath = req => { const { path, query } = req; const onlyMedia = isTruthy(query.only_media); switch (path) { case '/api/v1/streaming/user': return 'user'; case '/api/v1/streaming/user/notification': return 'user:notification'; case '/api/v1/streaming/public': return onlyMedia ? 'public:media' : 'public'; case '/api/v1/streaming/public/local': return onlyMedia ? 'public:local:media' : 'public:local'; case '/api/v1/streaming/public/remote': return onlyMedia ? 'public:remote:media' : 'public:remote'; case '/api/v1/streaming/hashtag': return 'hashtag'; case '/api/v1/streaming/hashtag/local': return 'hashtag:local'; case '/api/v1/streaming/direct': return 'direct'; case '/api/v1/streaming/list': return 'list'; default: return undefined; } }; const PUBLIC_CHANNELS = [ 'public', 'public:media', 'public:local', 'public:local:media', 'public:remote', 'public:remote:media', 'hashtag', 'hashtag:local', ]; /** * @param {any} req * @param {string} channelName * @return {Promise.} */ const checkScopes = (req, channelName) => new Promise((resolve, reject) => { log.silly(req.requestId, `Checking OAuth scopes for ${channelName}`); // When accessing public channels, no scopes are needed if (PUBLIC_CHANNELS.includes(channelName)) { resolve(); return; } // The `read` scope has the highest priority, if the token has it // then it can access all streams const requiredScopes = ['read']; // When accessing specifically the notifications stream, // we need a read:notifications, while in all other cases, // we can allow access with read:statuses. Mind that the // user stream will not contain notifications unless // the token has either read or read:notifications scope // as well, this is handled separately. if (channelName === 'user:notification') { requiredScopes.push('read:notifications'); } else { requiredScopes.push('read:statuses'); } if (req.scopes && requiredScopes.some(requiredScope => req.scopes.includes(requiredScope))) { resolve(); return; } const err = new Error('Access token does not cover required scopes'); err.status = 401; reject(err); }); /** * @param {any} info * @param {function(boolean, number, string): void} callback */ const wsVerifyClient = (info, callback) => { // When verifying the websockets connection, we no longer pre-emptively // check OAuth scopes and drop the connection if they're missing. We only // drop the connection if access without token is not allowed by environment // variables. OAuth scope checks are moved to the point of subscription // to a specific stream. accountFromRequest(info.req, alwaysRequireAuth).then(() => { callback(true, undefined, undefined); }).catch(err => { log.error(info.req.requestId, err.toString()); callback(false, 401, 'Unauthorized'); }); }; /** * @typedef SystemMessageHandlers * @property {function(): void} onKill */ /** * @param {any} req * @param {SystemMessageHandlers} eventHandlers * @return {function(string): void} */ const createSystemMessageListener = (req, eventHandlers) => { return message => { const json = parseJSON(message); if (!json) return; const { event } = json; log.silly(req.requestId, `System message for ${req.accountId}: ${event}`); if (event === 'kill') { log.verbose(req.requestId, `Closing connection for ${req.accountId} due to expired access token`); eventHandlers.onKill(); } }; }; /** * @param {any} req * @param {any} res */ const subscribeHttpToSystemChannel = (req, res) => { const systemChannelId = `timeline:access_token:${req.accessTokenId}`; const listener = createSystemMessageListener(req, { onKill() { res.end(); }, }); res.on('close', () => { unsubscribe(`${redisPrefix}${systemChannelId}`, listener); }); subscribe(`${redisPrefix}${systemChannelId}`, listener); }; /** * @param {any} req * @param {any} res * @param {function(Error=): void} next */ const authenticationMiddleware = (req, res, next) => { if (req.method === 'OPTIONS') { next(); return; } accountFromRequest(req, alwaysRequireAuth).then(() => checkScopes(req, channelNameFromPath(req))).then(() => { subscribeHttpToSystemChannel(req, res); }).then(() => { next(); }).catch(err => { next(err); }); }; /** * @param {Error} err * @param {any} req * @param {any} res * @param {function(Error=): void} next */ const errorMiddleware = (err, req, res, next) => { log.error(req.requestId, err.toString()); if (res.headersSent) { next(err); return; } res.writeHead(err.status || 500, { 'Content-Type': 'application/json' }); res.end(JSON.stringify({ error: err.status ? err.toString() : 'An unexpected error occurred' })); }; /** * @param {array} arr * @param {number=} shift * @return {string} */ const placeholders = (arr, shift = 0) => arr.map((_, i) => `$${i + 1 + shift}`).join(', '); /** * @param {string} listId * @param {any} req * @return {Promise.} */ const authorizeListAccess = (listId, req) => new Promise((resolve, reject) => { const { accountId } = req; pgPool.connect((err, client, done) => { if (err) { reject(); return; } client.query('SELECT id, account_id FROM lists WHERE id = $1 LIMIT 1', [listId], (err, result) => { done(); if (err || result.rows.length === 0 || result.rows[0].account_id !== accountId) { reject(); return; } resolve(); }); }); }); /** * @param {string[]} ids * @param {any} req * @param {function(string, string): void} output * @param {function(string[], function(string): void): void} attachCloseHandler * @param {boolean=} needsFiltering * @return {function(string): void} */ const streamFrom = (ids, req, output, attachCloseHandler, needsFiltering = false) => { const accountId = req.accountId || req.remoteAddress; log.verbose(req.requestId, `Starting stream from ${ids.join(', ')} for ${accountId}`); const listener = message => { const json = parseJSON(message); if (!json) return; const { event, payload, queued_at } = json; const transmit = () => { const now = new Date().getTime(); const delta = now - queued_at; const encodedPayload = typeof payload === 'object' ? JSON.stringify(payload) : payload; log.silly(req.requestId, `Transmitting for ${accountId}: ${event} ${encodedPayload} Delay: ${delta}ms`); output(event, encodedPayload); }; // Only messages that may require filtering are statuses, since notifications // are already personalized and deletes do not matter if (!needsFiltering || event !== 'update') { transmit(); return; } const unpackedPayload = payload; const targetAccountIds = [unpackedPayload.account.id].concat(unpackedPayload.mentions.map(item => item.id)); const accountDomain = unpackedPayload.account.acct.split('@')[1]; if (Array.isArray(req.chosenLanguages) && unpackedPayload.language !== null && req.chosenLanguages.indexOf(unpackedPayload.language) === -1) { log.silly(req.requestId, `Message ${unpackedPayload.id} filtered by language (${unpackedPayload.language})`); return; } // When the account is not logged in, it is not necessary to confirm the block or mute if (!req.accountId) { transmit(); return; } pgPool.connect((err, client, done) => { if (err) { log.error(err); return; } const queries = [ client.query(`SELECT 1 FROM blocks WHERE (account_id = $1 AND target_account_id IN (${placeholders(targetAccountIds, 2)})) OR (account_id = $2 AND target_account_id = $1) UNION SELECT 1 FROM mutes WHERE account_id = $1 AND target_account_id IN (${placeholders(targetAccountIds, 2)})`, [req.accountId, unpackedPayload.account.id].concat(targetAccountIds)), ]; if (accountDomain) { queries.push(client.query('SELECT 1 FROM account_domain_blocks WHERE account_id = $1 AND domain = $2', [req.accountId, accountDomain])); } Promise.all(queries).then(values => { done(); if (values[0].rows.length > 0 || (values.length > 1 && values[1].rows.length > 0)) { return; } transmit(); }).catch(err => { done(); log.error(err); }); }); }; ids.forEach(id => { subscribe(`${redisPrefix}${id}`, listener); }); if (attachCloseHandler) { attachCloseHandler(ids.map(id => `${redisPrefix}${id}`), listener); } return listener; }; /** * @param {any} req * @param {any} res * @return {function(string, string): void} */ const streamToHttp = (req, res) => { const accountId = req.accountId || req.remoteAddress; res.setHeader('Content-Type', 'text/event-stream'); res.setHeader('Cache-Control', 'no-store'); res.setHeader('Transfer-Encoding', 'chunked'); res.write(':)\n'); const heartbeat = setInterval(() => res.write(':thump\n'), 15000); req.on('close', () => { log.verbose(req.requestId, `Ending stream for ${accountId}`); clearInterval(heartbeat); }); return (event, payload) => { res.write(`event: ${event}\n`); res.write(`data: ${payload}\n\n`); }; }; /** * @param {any} req * @param {function(): void} [closeHandler] * @return {function(string[]): void} */ const streamHttpEnd = (req, closeHandler = undefined) => (ids) => { req.on('close', () => { ids.forEach(id => { unsubscribe(id); }); if (closeHandler) { closeHandler(); } }); }; /** * @param {any} req * @param {any} ws * @param {string[]} streamName * @return {function(string, string): void} */ const streamToWs = (req, ws, streamName) => (event, payload) => { if (ws.readyState !== ws.OPEN) { log.error(req.requestId, 'Tried writing to closed socket'); return; } ws.send(JSON.stringify({ stream: streamName, event, payload })); }; /** * @param {any} res */ const httpNotFound = res => { res.writeHead(404, { 'Content-Type': 'application/json' }); res.end(JSON.stringify({ error: 'Not found' })); }; app.use(setRequestId); app.use(setRemoteAddress); app.use(allowCrossDomain); app.get('/api/v1/streaming/health', (req, res) => { res.writeHead(200, { 'Content-Type': 'text/plain' }); res.end('OK'); }); app.use(authenticationMiddleware); app.use(errorMiddleware); app.get('/api/v1/streaming/*', (req, res) => { channelNameToIds(req, channelNameFromPath(req), req.query).then(({ channelIds, options }) => { const onSend = streamToHttp(req, res); const onEnd = streamHttpEnd(req, subscriptionHeartbeat(channelIds)); streamFrom(channelIds, req, onSend, onEnd, options.needsFiltering); }).catch(err => { log.verbose(req.requestId, 'Subscription error:', err.toString()); httpNotFound(res); }); }); const wss = new WebSocket.Server({ server, verifyClient: wsVerifyClient }); /** * @typedef StreamParams * @property {string} [tag] * @property {string} [list] * @property {string} [only_media] */ /** * @param {any} req * @return {string[]} */ const channelsForUserStream = req => { const arr = [`timeline:${req.accountId}`]; if (isInScope(req, ['crypto']) && req.deviceId) { arr.push(`timeline:${req.accountId}:${req.deviceId}`); } if (isInScope(req, ['read', 'read:notifications'])) { arr.push(`timeline:${req.accountId}:notifications`); } return arr; }; /** * @param {any} req * @param {string} name * @param {StreamParams} params * @return {Promise.<{ channelIds: string[], options: { needsFiltering: boolean } }>} */ const channelNameToIds = (req, name, params) => new Promise((resolve, reject) => { switch (name) { case 'user': resolve({ channelIds: channelsForUserStream(req), options: { needsFiltering: false }, }); break; case 'user:notification': resolve({ channelIds: [`timeline:${req.accountId}:notifications`], options: { needsFiltering: false }, }); break; case 'public': resolve({ channelIds: ['timeline:public'], options: { needsFiltering: true }, }); break; case 'public:local': resolve({ channelIds: ['timeline:public:local'], options: { needsFiltering: true }, }); break; case 'public:remote': resolve({ channelIds: ['timeline:public:remote'], options: { needsFiltering: true }, }); break; case 'public:media': resolve({ channelIds: ['timeline:public:media'], options: { needsFiltering: true }, }); break; case 'public:local:media': resolve({ channelIds: ['timeline:public:local:media'], options: { needsFiltering: true }, }); break; case 'public:remote:media': resolve({ channelIds: ['timeline:public:remote:media'], options: { needsFiltering: true }, }); break; case 'direct': resolve({ channelIds: [`timeline:direct:${req.accountId}`], options: { needsFiltering: false }, }); break; case 'hashtag': if (!params.tag || params.tag.length === 0) { reject('No tag for stream provided'); } else { resolve({ channelIds: [`timeline:hashtag:${params.tag.toLowerCase()}`], options: { needsFiltering: true }, }); } break; case 'hashtag:local': if (!params.tag || params.tag.length === 0) { reject('No tag for stream provided'); } else { resolve({ channelIds: [`timeline:hashtag:${params.tag.toLowerCase()}:local`], options: { needsFiltering: true }, }); } break; case 'list': authorizeListAccess(params.list, req).then(() => { resolve({ channelIds: [`timeline:list:${params.list}`], options: { needsFiltering: false }, }); }).catch(() => { reject('Not authorized to stream this list'); }); break; default: reject('Unknown stream type'); } }); /** * @param {string} channelName * @param {StreamParams} params * @return {string[]} */ const streamNameFromChannelName = (channelName, params) => { if (channelName === 'list') { return [channelName, params.list]; } else if (['hashtag', 'hashtag:local'].includes(channelName)) { return [channelName, params.tag]; } else { return [channelName]; } }; /** * @typedef WebSocketSession * @property {any} socket * @property {any} request * @property {Object.} subscriptions */ /** * @param {WebSocketSession} session * @param {string} channelName * @param {StreamParams} params */ const subscribeWebsocketToChannel = ({ socket, request, subscriptions }, channelName, params) => checkScopes(request, channelName).then(() => channelNameToIds(request, channelName, params)).then(({ channelIds, options, }) => { if (subscriptions[channelIds.join(';')]) { return; } const onSend = streamToWs(request, socket, streamNameFromChannelName(channelName, params)); const stopHeartbeat = subscriptionHeartbeat(channelIds); const listener = streamFrom(channelIds, request, onSend, undefined, options.needsFiltering); subscriptions[channelIds.join(';')] = { listener, stopHeartbeat, }; }).catch(err => { log.verbose(request.requestId, 'Subscription error:', err.toString()); socket.send(JSON.stringify({ error: err.toString() })); }); /** * @param {WebSocketSession} session * @param {string} channelName * @param {StreamParams} params */ const unsubscribeWebsocketFromChannel = ({ socket, request, subscriptions }, channelName, params) => channelNameToIds(request, channelName, params).then(({ channelIds }) => { log.verbose(request.requestId, `Ending stream from ${channelIds.join(', ')} for ${request.accountId}`); const subscription = subscriptions[channelIds.join(';')]; if (!subscription) { return; } const { listener, stopHeartbeat } = subscription; channelIds.forEach(channelId => { unsubscribe(`${redisPrefix}${channelId}`, listener); }); stopHeartbeat(); delete subscriptions[channelIds.join(';')]; }).catch(err => { log.verbose(request.requestId, 'Unsubscription error:', err); socket.send(JSON.stringify({ error: err.toString() })); }); /** * @param {WebSocketSession} session */ const subscribeWebsocketToSystemChannel = ({ socket, request, subscriptions }) => { const systemChannelId = `timeline:access_token:${request.accessTokenId}`; const listener = createSystemMessageListener(request, { onKill() { socket.close(); }, }); subscribe(`${redisPrefix}${systemChannelId}`, listener); subscriptions[systemChannelId] = { listener, stopHeartbeat: () => { }, }; }; /** * @param {string|string[]} arrayOrString * @return {string} */ const firstParam = arrayOrString => { if (Array.isArray(arrayOrString)) { return arrayOrString[0]; } else { return arrayOrString; } }; wss.on('connection', (ws, req) => { const location = url.parse(req.url, true); req.requestId = uuid.v4(); req.remoteAddress = ws._socket.remoteAddress; ws.isAlive = true; ws.on('pong', () => { ws.isAlive = true; }); /** * @type {WebSocketSession} */ const session = { socket: ws, request: req, subscriptions: {}, }; const onEnd = () => { const keys = Object.keys(session.subscriptions); keys.forEach(channelIds => { const { listener, stopHeartbeat } = session.subscriptions[channelIds]; channelIds.split(';').forEach(channelId => { unsubscribe(`${redisPrefix}${channelId}`, listener); }); stopHeartbeat(); }); }; ws.on('close', onEnd); ws.on('error', onEnd); ws.on('message', data => { const json = parseJSON(data); if (!json) return; const { type, stream, ...params } = json; if (type === 'subscribe') { subscribeWebsocketToChannel(session, firstParam(stream), params); } else if (type === 'unsubscribe') { unsubscribeWebsocketFromChannel(session, firstParam(stream), params); } else { // Unknown action type } }); subscribeWebsocketToSystemChannel(session); if (location.query.stream) { subscribeWebsocketToChannel(session, firstParam(location.query.stream), location.query); } }); setInterval(() => { wss.clients.forEach(ws => { if (ws.isAlive === false) { ws.terminate(); return; } ws.isAlive = false; ws.ping('', false); }); }, 30000); attachServerWithConfig(server, address => { log.warn(`Worker ${workerId} now listening on ${address}`); }); const onExit = () => { log.warn(`Worker ${workerId} exiting`); server.close(); process.exit(0); }; const onError = (err) => { log.error(err); server.close(); process.exit(0); }; process.on('SIGINT', onExit); process.on('SIGTERM', onExit); process.on('exit', onExit); process.on('uncaughtException', onError); }; /** * @param {any} server * @param {function(string): void} [onSuccess] */ const attachServerWithConfig = (server, onSuccess) => { if (process.env.SOCKET || process.env.PORT && isNaN(+process.env.PORT)) { server.listen(process.env.SOCKET || process.env.PORT, () => { if (onSuccess) { fs.chmodSync(server.address(), 0o666); onSuccess(server.address()); } }); } else { server.listen(+process.env.PORT || 4000, process.env.BIND || '127.0.0.1', () => { if (onSuccess) { onSuccess(`${server.address().address}:${server.address().port}`); } }); } }; /** * @param {function(Error=): void} onSuccess */ const onPortAvailable = onSuccess => { const testServer = http.createServer(); testServer.once('error', err => { onSuccess(err); }); testServer.once('listening', () => { testServer.once('close', () => onSuccess()); testServer.close(); }); attachServerWithConfig(testServer); }; onPortAvailable(err => { if (err) { log.error('Could not start server, the port or socket is in use'); return; } throng({ workers: numWorkers, lifetime: Infinity, start: startWorker, master: startMaster, }); });