Merge pull request #170 from Cryptkeeper/dns-perf

5.4.3 release

config.json

@@ -9,10 +9,6 @@
 		"pingAll": 3000,
 		"connectTimeout": 2500
 	},
-	"performance": {
-		"skipUnfurlSrv": false,
-		"unfurlSrvCacheTtl": 120000
-	},
 	"logToDatabase": false,
 	"graphDuration": 86400000,
 	"serverGraphDuration": 180000

docs/CHANGELOG.md

@@ -1,3 +1,7 @@
+**5.4.3** *(May 14 2020)*
+- Added support for the optional field `config->skipSrvTimeout` in `config.json`. If a configured server does not return a valid response when unfurling potential SRV records, it will avoid re-unfurling SRV records for this duration in milliseconds. Use a value of `0` to disable this feature altogether.
+- Removes support for the `config->performance->skipUnfurlSrv` and `config->performance->unfurlSrvCacheTtl` fields in `config.json
+
 **5.4.2** *(May 13 2020)*
 - Fixes a typo causing `_minecraft._tcp.*` SRV records to not resolve.
 

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 => {

lib/dns.js

@@ -0,0 +1,75 @@
+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) {
+        // Compare config.skipSrvTimeout directly since SKIP_SRV_TIMEOUT has an or'd value
+        // isValidSkipSrvTimeout == whether the config has a valid skipSrvTimeout value set
+        const isValidSkipSrvTimeout = typeof config.skipSrvTimeout === 'number' && config.skipSrvTimeout > 0
+
+        // Only activate _skipSrv if the skipSrvTimeout value is either NaN or > 0
+        // 0 represents a disabled flag
+        if (!this._isSkipSrv() && isValidSkipSrvTimeout) {
+          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

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
 })

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 {

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

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)
   }

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.')
 

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "minetrack",
-  "version": "5.4.2",
+  "version": "5.4.3",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "minetrack",
-  "version": "5.4.2",
+  "version": "5.4.3",
   "description": "A Minecraft server tracker that lets you focus on the basics.",
   "main": "main.js",
   "dependencies": {