server/models/request.js

   1 'use strict'
   2
   3 const each = require('async/each')
   4 const eachLimit = require('async/eachLimit')
   5 const waterfall = require('async/waterfall')
   6 const values = require('lodash/values')
   7
   8 const constants = require('../initializers/constants')
   9 const logger = require('../helpers/logger')
  10 const requests = require('../helpers/requests')
  11
  12 let timer = null
  13 let lastRequestTimestamp = 0
  14
  15 // ---------------------------------------------------------------------------
  16
  17 module.exports = function (sequelize, DataTypes) {
  18   const Request = sequelize.define('Request',
  19     {
  20       request: {
  21         type: DataTypes.JSON,
  22         allowNull: false
  23       },
  24       endpoint: {
  25         type: DataTypes.ENUM(values(constants.REQUEST_ENDPOINTS)),
  26         allowNull: false
  27       }
  28     },
  29     {
  30       classMethods: {
  31         associate,
  32
  33         activate,
  34         countTotalRequests,
  35         deactivate,
  36         flush,
  37         forceSend,
  38         remainingMilliSeconds
  39       }
  40     }
  41   )
  42
  43   return Request
  44 }
  45
  46 // ------------------------------ STATICS ------------------------------
  47
  48 function associate (models) {
  49   this.belongsToMany(models.Pod, {
  50     foreignKey: {
  51       name: 'requestId',
  52       allowNull: false
  53     },
  54     through: models.RequestToPod,
  55     onDelete: 'CASCADE'
  56   })
  57 }
  58
  59 function activate () {
  60   logger.info('Requests scheduler activated.')
  61   lastRequestTimestamp = Date.now()
  62
  63   const self = this
  64   timer = setInterval(function () {
  65     lastRequestTimestamp = Date.now()
  66     makeRequests.call(self)
  67   }, constants.REQUESTS_INTERVAL)
  68 }
  69
  70 function countTotalRequests (callback) {
  71   const query = {
  72     include: [ this.sequelize.models.Pod ]
  73   }
  74
  75   return this.count(query).asCallback(callback)
  76 }
  77
  78 function deactivate () {
  79   logger.info('Requests scheduler deactivated.')
  80   clearInterval(timer)
  81   timer = null
  82 }
  83
  84 function flush (callback) {
  85   removeAll.call(this, function (err) {
  86     if (err) logger.error('Cannot flush the requests.', { error: err })
  87
  88     return callback(err)
  89   })
  90 }
  91
  92 function forceSend () {
  93   logger.info('Force requests scheduler sending.')
  94   makeRequests.call(this)
  95 }
  96
  97 function remainingMilliSeconds () {
  98   if (timer === null) return -1
  99
 100   return constants.REQUESTS_INTERVAL - (Date.now() - lastRequestTimestamp)
 101 }
 102
 103 // ---------------------------------------------------------------------------
 104
 105 // Make a requests to friends of a certain type
 106 function makeRequest (toPod, requestEndpoint, requestsToMake, callback) {
 107   if (!callback) callback = function () {}
 108
 109   const params = {
 110     toPod: toPod,
 111     sign: true, // Prove our identity
 112     method: 'POST',
 113     path: '/api/' + constants.API_VERSION + '/remote/' + requestEndpoint,
 114     data: requestsToMake // Requests we need to make
 115   }
 116
 117   // Make multiple retry requests to all of pods
 118   // The function fire some useful callbacks
 119   requests.makeSecureRequest(params, function (err, res) {
 120     if (err || (res.statusCode !== 200 && res.statusCode !== 201 && res.statusCode !== 204)) {
 121       logger.error(
 122         'Error sending secure request to %s pod.',
 123         toPod.host,
 124         {
 125           error: err || new Error('Status code not 20x : ' + res.statusCode)
 126         }
 127       )
 128
 129       return callback(false)
 130     }
 131
 132     return callback(true)
 133   })
 134 }
 135
 136 // Make all the requests of the scheduler
 137 function makeRequests () {
 138   const self = this
 139   const RequestToPod = this.sequelize.models.RequestToPod
 140
 141   // We limit the size of the requests (REQUESTS_LIMIT)
 142   // We don't want to stuck with the same failing requests so we get a random list
 143   listWithLimitAndRandom.call(self, constants.REQUESTS_LIMIT, function (err, requests) {
 144     if (err) {
 145       logger.error('Cannot get the list of requests.', { err: err })
 146       return // Abort
 147     }
 148
 149     // If there are no requests, abort
 150     if (requests.length === 0) {
 151       logger.info('No requests to make.')
 152       return
 153     }
 154
 155     logger.info('Making requests to friends.')
 156
 157     // We want to group requests by destinations pod and endpoint
 158     const requestsToMakeGrouped = {}
 159
 160     requests.forEach(function (request) {
 161       request.Pods.forEach(function (toPod) {
 162         const hashKey = toPod.id + request.endpoint
 163         if (!requestsToMakeGrouped[hashKey]) {
 164           requestsToMakeGrouped[hashKey] = {
 165             toPodId: toPod.id,
 166             endpoint: request.endpoint,
 167             ids: [], // request ids, to delete them from the DB in the future
 168             datas: [] // requests data,
 169           }
 170         }
 171
 172         requestsToMakeGrouped[hashKey].ids.push(request.id)
 173         requestsToMakeGrouped[hashKey].datas.push(request.request)
 174       })
 175     })
 176
 177     const goodPods = []
 178     const badPods = []
 179
 180     eachLimit(Object.keys(requestsToMakeGrouped), constants.REQUESTS_IN_PARALLEL, function (hashKey, callbackEach) {
 181       const requestToMake = requestsToMakeGrouped[hashKey]
 182
 183       // FIXME: SQL request inside a loop :/
 184       self.sequelize.models.Pod.load(requestToMake.toPodId, function (err, toPod) {
 185         if (err) {
 186           logger.error('Error finding pod by id.', { err: err })
 187           return callbackEach()
 188         }
 189
 190         // Maybe the pod is not our friend anymore so simply remove it
 191         if (!toPod) {
 192           const requestIdsToDelete = requestToMake.ids
 193
 194           logger.info('Removing %d requests of unexisting pod %s.', requestIdsToDelete.length, requestToMake.toPodId)
 195           RequestToPod.removePodOf.call(self, requestIdsToDelete, requestToMake.toPodId)
 196           return callbackEach()
 197         }
 198
 199         makeRequest(toPod, requestToMake.endpoint, requestToMake.datas, function (success) {
 200           if (success === true) {
 201             logger.debug('Removing requests for pod %s.', requestToMake.toPodId, { requestsIds: requestToMake.ids })
 202
 203             goodPods.push(requestToMake.toPodId)
 204
 205             // Remove the pod id of these request ids
 206             RequestToPod.removePodOf(requestToMake.ids, requestToMake.toPodId, callbackEach)
 207           } else {
 208             badPods.push(requestToMake.toPodId)
 209             callbackEach()
 210           }
 211         })
 212       })
 213     }, function () {
 214       // All the requests were made, we update the pods score
 215       updatePodsScore.call(self, goodPods, badPods)
 216       // Flush requests with no pod
 217       removeWithEmptyTo.call(self, function (err) {
 218         if (err) logger.error('Error when removing requests with no pods.', { error: err })
 219       })
 220     })
 221   })
 222 }
 223
 224 // Remove pods with a score of 0 (too many requests where they were unreachable)
 225 function removeBadPods () {
 226   const self = this
 227
 228   waterfall([
 229     function findBadPods (callback) {
 230       self.sequelize.models.Pod.listBadPods(function (err, pods) {
 231         if (err) {
 232           logger.error('Cannot find bad pods.', { error: err })
 233           return callback(err)
 234         }
 235
 236         return callback(null, pods)
 237       })
 238     },
 239
 240     function removeTheseBadPods (pods, callback) {
 241       each(pods, function (pod, callbackEach) {
 242         pod.destroy().asCallback(callbackEach)
 243       }, function (err) {
 244         return callback(err, pods.length)
 245       })
 246     }
 247   ], function (err, numberOfPodsRemoved) {
 248     if (err) {
 249       logger.error('Cannot remove bad pods.', { error: err })
 250     } else if (numberOfPodsRemoved) {
 251       logger.info('Removed %d pods.', numberOfPodsRemoved)
 252     } else {
 253       logger.info('No need to remove bad pods.')
 254     }
 255   })
 256 }
 257
 258 function updatePodsScore (goodPods, badPods) {
 259   const self = this
 260   const Pod = this.sequelize.models.Pod
 261
 262   logger.info('Updating %d good pods and %d bad pods scores.', goodPods.length, badPods.length)
 263
 264   if (goodPods.length !== 0) {
 265     Pod.incrementScores(goodPods, constants.PODS_SCORE.BONUS, function (err) {
 266       if (err) logger.error('Cannot increment scores of good pods.', { error: err })
 267     })
 268   }
 269
 270   if (badPods.length !== 0) {
 271     Pod.incrementScores(badPods, constants.PODS_SCORE.MALUS, function (err) {
 272       if (err) logger.error('Cannot decrement scores of bad pods.', { error: err })
 273       removeBadPods.call(self)
 274     })
 275   }
 276 }
 277
 278 function listWithLimitAndRandom (limit, callback) {
 279   const self = this
 280
 281   self.count().asCallback(function (err, count) {
 282     if (err) return callback(err)
 283
 284     // Optimization...
 285     if (count === 0) return callback(null, [])
 286
 287     let start = Math.floor(Math.random() * count) - limit
 288     if (start < 0) start = 0
 289
 290     const query = {
 291       order: [
 292         [ 'id', 'ASC' ]
 293       ],
 294       offset: start,
 295       limit: limit,
 296       include: [ this.sequelize.models.Pod ]
 297     }
 298
 299     self.findAll(query).asCallback(callback)
 300   })
 301 }
 302
 303 function removeAll (callback) {
 304   // Delete all requests
 305   this.truncate({ cascade: true }).asCallback(callback)
 306 }
 307
 308 function removeWithEmptyTo (callback) {
 309   if (!callback) callback = function () {}
 310
 311   const query = {
 312     where: {
 313       id: {
 314         $notIn: [
 315           this.sequelize.literal('SELECT "requestId" FROM "RequestToPods"')
 316         ]
 317       }
 318     }
 319   }
 320
 321   this.destroy(query).asCallback(callback)
 322 }