From 9a38160019f9e90ac3af5b4a3a9d269cbe955686 Mon Sep 17 00:00:00 2001 From: Nick Krecklow Date: Thu, 14 May 2020 20:30:40 -0500 Subject: [PATCH] replace ServerRegistration#unfurlSrv to DNSResolver class --- config.json | 4 --- lib/database.js | 4 ++- lib/dns.js | 69 +++++++++++++++++++++++++++++++++++++++++++++++++ lib/logger.js | 2 +- lib/ping.js | 4 +-- lib/servers.js | 59 ++---------------------------------------- lib/time.js | 6 ++++- main.js | 9 ------- 8 files changed, 82 insertions(+), 75 deletions(-) create mode 100644 lib/dns.js diff --git a/config.json b/config.json index e96bca1..ebe2d93 100644 --- a/config.json +++ b/config.json @@ -9,10 +9,6 @@ "pingAll": 3000, "connectTimeout": 2500 }, - "performance": { - "skipUnfurlSrv": false, - "unfurlSrvCacheTtl": 120000 - }, "logToDatabase": false, "graphDuration": 86400000, "serverGraphDuration": 180000 diff --git a/lib/database.js b/lib/database.js index 60f795a..16e5190 100644 --- a/lib/database.js +++ b/lib/database.js @@ -1,5 +1,7 @@ const sqlite = require('sqlite3') +const TimeTracker = require('./time') + class Database { constructor (app) { this._app = app @@ -16,7 +18,7 @@ class Database { loadGraphPoints (graphDuration, callback) { // Query recent pings - const endTime = new Date().getTime() + const endTime = TimeTracker.getEpochMillis() const startTime = endTime - graphDuration this.getRecentPings(startTime, endTime, pingData => { diff --git a/lib/dns.js b/lib/dns.js new file mode 100644 index 0000000..e2ab8ff --- /dev/null +++ b/lib/dns.js @@ -0,0 +1,69 @@ +const dns = require('dns') + +const logger = require('./logger') +const TimeTracker = require('./time') + +const config = require('../config') + +const SKIP_SRV_TIMEOUT = config.skipSrvTimeout || 60 * 60 * 1000 + +class DNSResolver { + constructor (ip, port) { + this._ip = ip + this._port = port + } + + _skipSrv () { + this._skipSrvUntil = TimeTracker.getEpochMillis() + SKIP_SRV_TIMEOUT + } + + _isSkipSrv () { + return this._skipSrvUntil && TimeTracker.getEpochMillis() <= this._skipSrvUntil + } + + resolve (callback) { + if (this._isSkipSrv()) { + callback(this._ip, this._port, config.rates.connectTimeout) + + return + } + + const startTime = TimeTracker.getEpochMillis() + + let callbackFired = false + + const fireCallback = (ip, port) => { + if (!callbackFired) { + callbackFired = true + + // Send currentTime - startTime to provide remaining connectionTime allowance + callback(ip || this._ip, port || this._port, TimeTracker.getEpochMillis() - startTime) + } + } + + const timeoutCallback = setTimeout(fireCallback, config.rates.connectTimeout) + + dns.resolveSrv('_minecraft._tcp.' + this._ip, (err, records) => { + // Cancel the timeout handler if not already fired + if (!callbackFired) { + clearTimeout(timeoutCallback) + } + + // Test if the error indicates a miss, or if the records returned are empty + if ((err && (err.code === 'ENOTFOUND' || err.code === 'ENODATA')) || !records || records.length === 0) { + if (!this._isSkipSrv()) { + this._skipSrv() + + logger.log('warn', 'No SRV records were resolved for %s. Minetrack will skip attempting to resolve %s SRV records for %d minutes.', this._ip, this._ip, SKIP_SRV_TIMEOUT / (60 * 1000)) + } + + fireCallback() + } else { + // Only fires if !err && records.length > 0 + fireCallback(records[0].name, records[0].port) + } + }) + } +} + +module.exports = DNSResolver diff --git a/lib/logger.js b/lib/logger.js index ea99dd7..82237f6 100644 --- a/lib/logger.js +++ b/lib/logger.js @@ -9,7 +9,7 @@ winston.add(winston.transports.File, { winston.add(winston.transports.Console, { timestamp: () => { const date = new Date() - return date.toLocaleTimeString() + ' ' + date.getDate() + '/' + (date.getMonth() + 1) + '/' + date.getFullYear().toString().substring(2, 4) + return date.toLocaleTimeString() + ' ' + date.toLocaleDateString() }, colorize: true }) diff --git a/lib/ping.js b/lib/ping.js index 82d7e33..12901a0 100644 --- a/lib/ping.js +++ b/lib/ping.js @@ -9,10 +9,10 @@ const config = require('../config') function ping (serverRegistration, timeout, callback, version) { switch (serverRegistration.data.type) { case 'PC': - serverRegistration.unfurlSrv((host, port) => { + serverRegistration.dnsResolver.unfurlSrv((host, port, remainingTimeout) => { const server = new minecraftJavaPing.MinecraftServer(host, port || 25565) - server.ping(timeout, version, (err, res) => { + server.ping(remainingTimeout, version, (err, res) => { if (err) { callback(err) } else { diff --git a/lib/servers.js b/lib/servers.js index 211ae91..d6231a6 100644 --- a/lib/servers.js +++ b/lib/servers.js @@ -1,6 +1,6 @@ const crypto = require('crypto') -const dns = require('dns') +const DNSResolver = require('./dns') const TimeTracker = require('./time') const Server = require('./server') @@ -18,6 +18,7 @@ class ServerRegistration { this.serverId = serverId this.data = data this._pingHistory = [] + this.dnsResolver = new DNSResolver(this.data.ip, this.data.port) } handlePing (timestamp, resp, err, version) { @@ -310,62 +311,6 @@ class ServerRegistration { color: this.data.color } } - - unfurlSrv (callback) { - // Skip unfurling SRV, instantly return pre-configured data - if (config.performance && config.performance.skipUnfurlSrv) { - callback(this.data.ip, this.data.port) - return - } - - const timestamp = new Date().getTime() - - // If a cached copy exists and is within its TTL, instantly return - if (this._lastUnfurlSrv && timestamp - this._lastUnfurlSrv.timestamp <= config.performance.unfurlSrvCacheTtl) { - callback(this._lastUnfurlSrv.ip, this._lastUnfurlSrv.port) - return - } - - // Group callbacks into an array - // Once resolved, fire callbacks sequentially - // This avoids callbacks possibly executing out of order - if (!this._unfurlSrvCallbackQueue) { - this._unfurlSrvCallbackQueue = [] - } - - this._unfurlSrvCallbackQueue.push(callback) - - // Prevent multiple #resolveSrv calls per ServerRegistration - if (!this._isUnfurlingSrv) { - this._isUnfurlingSrv = true - - dns.resolveSrv('_minecraft._tcp.' + this.data.ip, (_, records) => { - this._lastUnfurlSrv = { - timestamp - } - - if (records && records.length > 0) { - this._lastUnfurlSrv.ip = records[0].name - this._lastUnfurlSrv.port = records[0].port - } else { - // Provide fallback to pre-configured data - this._lastUnfurlSrv.ip = this.data.ip - this._lastUnfurlSrv.port = this.data.port - } - - // Fire the waiting callbacks in queue - // Release blocking flag to allow new #resolveSrv calls - this._isUnfurlingSrv = false - - for (const callback of this._unfurlSrvCallbackQueue) { - callback(this._lastUnfurlSrv.ip, this._lastUnfurlSrv.port) - } - - // Reset the callback queue - this._unfurlSrvCallbackQueue = [] - }) - } - } } module.exports = ServerRegistration diff --git a/lib/time.js b/lib/time.js index 966272a..57386e2 100644 --- a/lib/time.js +++ b/lib/time.js @@ -7,7 +7,7 @@ class TimeTracker { } newTimestamp () { - const timestamp = new Date().getTime() + const timestamp = TimeTracker.getEpochMillis() this._points.push(timestamp) @@ -22,6 +22,10 @@ class TimeTracker { return this._points } + static getEpochMillis () { + return new Date().getTime() + } + static getMaxServerGraphDataLength () { return Math.ceil(config.serverGraphDuration / config.rates.pingAll) } diff --git a/main.js b/main.js index e0518f7..968df18 100644 --- a/main.js +++ b/main.js @@ -30,15 +30,6 @@ if (!config.serverGraphDuration) { config.serverGraphDuration = 3 * 60 * 10000 } -if (config.performance && config.performance.skipUnfurlSrv) { - logger.log('warn', '"performance.skipUnfurlSrv" is enabled. Any configured hosts using SRV records may not properly resolve.') -} - -if (!config.performance || typeof config.performance.unfurlSrvCacheTtl === 'undefined') { - logger.log('warn', '"performance.unfurlSrvCacheTtl" is not defined in config.json - defaulting to 120 seconds!') - config.performance.unfurlSrvCacheTtl = 2 * 60 * 1000 -} - if (!config.logToDatabase) { logger.log('warn', 'Database logging is not enabled. You can enable it by setting "logToDatabase" to true in config.json. This requires sqlite3 to be installed.')