v3 migration: first finished version that contains all models

migrations/api_v3/challengesMembers.js

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+// Migrate challenges members
+// Run AFTER users migration
+
+// The console-stamp module must be installed (not included in package.json)
+
+// It requires two environment variables: MONGODB_OLD and MONGODB_NEW
+
+// Due to some big user profiles it needs more RAM than is allowed by default by v8 (arounf 1.7GB).
+// Run the script with --max-old-space-size=4096 to allow up to 4GB of RAM
+console.log('Starting migrations/api_v3/challengesMembers.js.');
+
+require('babel-register');
+
+var Q = require('q');
+var MongoDB = require('mongodb');
+var nconf = require('nconf');
+var mongoose = require('mongoose');
+var _ = require('lodash');
+var uuid = require('uuid');
+var consoleStamp = require('console-stamp');
+
+// Add timestamps to console messages
+consoleStamp(console);
+
+// Initialize configuration
+require('../../website/src/libs/api-v3/setupNconf')();
+
+var MONGODB_OLD = nconf.get('MONGODB_OLD');
+var MONGODB_NEW = nconf.get('MONGODB_NEW');
+
+var MongoClient = MongoDB.MongoClient;
+
+mongoose.Promise = Q.Promise; // otherwise mongoose models won't work
+
+// To be defined later when MongoClient connects
+var mongoDbOldInstance;
+var oldChallengeCollection;
+
+var mongoDbNewInstance;
+var newUserCollection;
+
+var BATCH_SIZE = 1000;
+
+var processedChallenges = 0;
+
+// Only process challenges that fall in a interval ie -> up to 0000-4000-0000-0000
+var AFTER_CHALLENGE_ID = nconf.get('AFTER_CHALLENGE_ID');
+var BEFORE_CHALLENGE_ID = nconf.get('BEFORE_CHALLENGE_ID');
+
+function processChallenges (afterId) {
+  var processedTasks = 0;
+  var lastChallenge = null;
+  var oldChallenges;
+
+  var query = {};
+
+  if (BEFORE_CHALLENGE_ID) {
+    query._id = {$lte: BEFORE_CHALLENGE_ID};
+  }
+
+  if ((afterId || AFTER_CHALLENGE_ID) && !query._id) {
+    query._id = {};
+  }
+
+  if (afterId) {
+    query._id.$gt = afterId;
+  } else if (AFTER_CHALLENGE_ID) {
+    query._id.$gt = AFTER_CHALLENGE_ID;
+  }
+
+  console.log(`Executing challenges query.\nMatching challenges after ${afterId ? afterId : AFTER_CHALLENGE_ID} and before ${BEFORE_CHALLENGE_ID} (included).`);
+
+  return oldChallengeCollection
+  .find(query)
+  .sort({_id: 1})
+  .limit(BATCH_SIZE)
+  .toArray()
+  .then(function (oldChallengesR) {
+    oldChallenges = oldChallengesR;
+
+    var promises = [];
+
+    console.log(`Processing ${oldChallenges.length} challenges. Already processed ${processedChallenges} challenges.`);
+
+    if (oldChallenges.length === BATCH_SIZE) {
+      lastChallenge = oldChallenges[oldChallenges.length - 1]._id;
+    }
+
+    oldChallenges.forEach(function (oldChallenge) {
+      promises.push(newUserCollection.updateMany({
+        _id: {$in: oldChallenge.members},
+      }, {
+        $push: {challenges: oldChallenge._id},
+      }, {multi: true}));
+    });
+
+    console.log(`Migrating members of ${oldChallenges.length} challenges.`);
+
+    return Q.all(promises);
+  })
+  .then(function () {
+    processedChallenges += oldChallenges.length;
+
+    console.log(`Migrated members of ${oldChallenges.length} challenges.`);
+
+    if (lastChallenge) {
+      return processChallenges(lastChallenge);
+    } else {
+      return console.log('Done!');
+    }
+  });
+}
+
+// Connect to the databases
+Q.all([
+  MongoClient.connect(MONGODB_OLD),
+  MongoClient.connect(MONGODB_NEW),
+])
+.then(function (result) {
+  var oldInstance = result[0];
+  var newInstance = result[1];
+
+  mongoDbOldInstance = oldInstance;
+  oldChallengeCollection = mongoDbOldInstance.collection('challenges');
+
+  mongoDbNewInstance = newInstance;
+  newUserCollection = mongoDbNewInstance.collection('users');
+
+  console.log(`Connected with MongoClient to ${MONGODB_OLD} and ${MONGODB_NEW}.`);
+
+  return processChallenges();
+})
+.catch(function (err) {
+  console.error(err.stack || err);
+});