server/models/request.js

   1 'use strict'
   2
   3 const each = require('async/each')
   4 const eachLimit = require('async/eachLimit')
   5 const values = require('lodash/values')
   6 const mongoose = require('mongoose')
   7 const waterfall = require('async/waterfall')
   8
   9 const constants = require('../initializers/constants')
  10 const logger = require('../helpers/logger')
  11 const requests = require('../helpers/requests')
  12
  13 const Pod = mongoose.model('Pod')
  14
  15 let timer = null
  16 let lastRequestTimestamp = 0
  17
  18 // ---------------------------------------------------------------------------
  19
  20 const RequestSchema = mongoose.Schema({
  21   request: mongoose.Schema.Types.Mixed,
  22   endpoint: {
  23     type: String,
  24     enum: [ values(constants.REQUEST_ENDPOINTS) ]
  25   },
  26   to: [
  27     {
  28       type: mongoose.Schema.Types.ObjectId,
  29       ref: 'Pod'
  30     }
  31   ]
  32 })
  33
  34 RequestSchema.statics = {
  35   activate,
  36   deactivate,
  37   flush,
  38   forceSend,
  39   list,
  40   remainingMilliSeconds
  41 }
  42
  43 RequestSchema.pre('save', function (next) {
  44   const self = this
  45
  46   if (self.to.length === 0) {
  47     Pod.listAllIds(function (err, podIds) {
  48       if (err) return next(err)
  49
  50       // No friends
  51       if (podIds.length === 0) return
  52
  53       self.to = podIds
  54       return next()
  55     })
  56   } else {
  57     return next()
  58   }
  59 })
  60
  61 mongoose.model('Request', RequestSchema)
  62
  63 // ------------------------------ STATICS ------------------------------
  64
  65 function activate () {
  66   logger.info('Requests scheduler activated.')
  67   lastRequestTimestamp = Date.now()
  68
  69   const self = this
  70   timer = setInterval(function () {
  71     lastRequestTimestamp = Date.now()
  72     makeRequests.call(self)
  73   }, constants.REQUESTS_INTERVAL)
  74 }
  75
  76 function deactivate () {
  77   logger.info('Requests scheduler deactivated.')
  78   clearInterval(timer)
  79   timer = null
  80 }
  81
  82 function flush () {
  83   removeAll.call(this, function (err) {
  84     if (err) logger.error('Cannot flush the requests.', { error: err })
  85   })
  86 }
  87
  88 function forceSend () {
  89   logger.info('Force requests scheduler sending.')
  90   makeRequests.call(this)
  91 }
  92
  93 function list (callback) {
  94   this.find({ }, callback)
  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
 140   // We limit the size of the requests (REQUESTS_LIMIT)
 141   // We don't want to stuck with the same failing requests so we get a random list
 142   listWithLimitAndRandom.call(self, constants.REQUESTS_LIMIT, function (err, requests) {
 143     if (err) {
 144       logger.error('Cannot get the list of requests.', { err: err })
 145       return // Abort
 146     }
 147
 148     // If there are no requests, abort
 149     if (requests.length === 0) {
 150       logger.info('No requests to make.')
 151       return
 152     }
 153
 154     logger.info('Making requests to friends.')
 155
 156     // We want to group requests by destinations pod and endpoint
 157     const requestsToMakeGrouped = {}
 158
 159     requests.forEach(function (poolRequest) {
 160       poolRequest.to.forEach(function (toPodId) {
 161         const hashKey = toPodId + poolRequest.endpoint
 162         if (!requestsToMakeGrouped[hashKey]) {
 163           requestsToMakeGrouped[hashKey] = {
 164             toPodId,
 165             endpoint: poolRequest.endpoint,
 166             ids: [], // pool request ids, to delete them from the DB in the future
 167             datas: [] // requests data,
 168           }
 169         }
 170
 171         requestsToMakeGrouped[hashKey].ids.push(poolRequest._id)
 172         requestsToMakeGrouped[hashKey].datas.push(poolRequest.request)
 173       })
 174     })
 175
 176     const goodPods = []
 177     const badPods = []
 178
 179     eachLimit(Object.keys(requestsToMakeGrouped), constants.REQUESTS_IN_PARALLEL, function (hashKey, callbackEach) {
 180       const requestToMake = requestsToMakeGrouped[hashKey]
 181
 182       // FIXME: mongodb request inside a loop :/
 183       Pod.load(requestToMake.toPodId, function (err, toPod) {
 184         if (err) {
 185           logger.error('Error finding pod by id.', { err: err })
 186           return callbackEach()
 187         }
 188
 189         // Maybe the pod is not our friend anymore so simply remove it
 190         if (!toPod) {
 191           const requestIdsToDelete = requestToMake.ids
 192
 193           logger.info('Removing %d requests of unexisting pod %s.', requestIdsToDelete.length, requestToMake.toPodId)
 194           removePodOf.call(self, requestIdsToDelete, requestToMake.toPodId)
 195           return callbackEach()
 196         }
 197
 198         makeRequest(toPod, requestToMake.endpoint, requestToMake.datas, function (success) {
 199           if (success === true) {
 200             logger.debug('Removing requests for %s pod.', requestToMake.toPodId, { requestsIds: requestToMake.ids })
 201
 202             goodPods.push(requestToMake.toPodId)
 203
 204             // Remove the pod id of these request ids
 205             removePodOf.call(self, requestToMake.ids, requestToMake.toPodId, callbackEach)
 206           } else {
 207             badPods.push(requestToMake.toPodId)
 208             callbackEach()
 209           }
 210         })
 211       })
 212     }, function () {
 213       // All the requests were made, we update the pods score
 214       updatePodsScore(goodPods, badPods)
 215       // Flush requests with no pod
 216       removeWithEmptyTo.call(self)
 217     })
 218   })
 219 }
 220
 221 // Remove pods with a score of 0 (too many requests where they were unreachable)
 222 function removeBadPods () {
 223   waterfall([
 224     function findBadPods (callback) {
 225       Pod.listBadPods(function (err, pods) {
 226         if (err) {
 227           logger.error('Cannot find bad pods.', { error: err })
 228           return callback(err)
 229         }
 230
 231         return callback(null, pods)
 232       })
 233     },
 234
 235     function removeTheseBadPods (pods, callback) {
 236       if (pods.length === 0) return callback(null, 0)
 237
 238       each(pods, function (pod, callbackEach) {
 239         pod.remove(callbackEach)
 240       }, function (err) {
 241         return callback(err, pods.length)
 242       })
 243     }
 244   ], function (err, numberOfPodsRemoved) {
 245     if (err) {
 246       logger.error('Cannot remove bad pods.', { error: err })
 247     } else if (numberOfPodsRemoved) {
 248       logger.info('Removed %d pods.', numberOfPodsRemoved)
 249     } else {
 250       logger.info('No need to remove bad pods.')
 251     }
 252   })
 253 }
 254
 255 function updatePodsScore (goodPods, badPods) {
 256   logger.info('Updating %d good pods and %d bad pods scores.', goodPods.length, badPods.length)
 257
 258   Pod.incrementScores(goodPods, constants.PODS_SCORE.BONUS, function (err) {
 259     if (err) logger.error('Cannot increment scores of good pods.')
 260   })
 261
 262   Pod.incrementScores(badPods, constants.PODS_SCORE.MALUS, function (err) {
 263     if (err) logger.error('Cannot decrement scores of bad pods.')
 264     removeBadPods()
 265   })
 266 }
 267
 268 function listWithLimitAndRandom (limit, callback) {
 269   const self = this
 270
 271   self.count(function (err, count) {
 272     if (err) return callback(err)
 273
 274     let start = Math.floor(Math.random() * count) - limit
 275     if (start < 0) start = 0
 276
 277     self.find().sort({ _id: 1 }).skip(start).limit(limit).exec(callback)
 278   })
 279 }
 280
 281 function removeAll (callback) {
 282   this.remove({ }, callback)
 283 }
 284
 285 function removePodOf (requestsIds, podId, callback) {
 286   if (!callback) callback = function () {}
 287
 288   this.update({ _id: { $in: requestsIds } }, { $pull: { to: podId } }, { multi: true }, callback)
 289 }
 290
 291 function removeWithEmptyTo (callback) {
 292   if (!callback) callback = function () {}
 293
 294   this.remove({ to: { $size: 0 } }, callback)
 295 }