+'use strict'
+
+const retry = require('async/retry')
+
+const db = require('../initializers/database')
+const logger = require('./logger')
+
+const utils = {
+ retryTransactionWrapper,
+ transactionRetryer,
+ startSerializableTransaction
+}
+
+// { arguments, errorMessage }
+function retryTransactionWrapper (functionToRetry, options, finalCallback) {
+ const args = options.arguments ? options.arguments : []
+
+ utils.transactionRetryer(
+ function (callback) {
+ return functionToRetry.apply(this, args.concat([ callback ]))
+ },
+ function (err) {
+ if (err) {
+ logger.error(options.errorMessage, { error: err })
+ }
+
+ // Do not return the error, continue the process
+ return finalCallback(null)
+ }
+ )
+}
+
+function transactionRetryer (func, callback) {
+ retry({
+ times: 5,
+
+ errorFilter: function (err) {
+ const willRetry = (err.name === 'SequelizeDatabaseError')
+ logger.debug('Maybe retrying the transaction function.', { willRetry })
+ return willRetry
+ }
+ }, func, callback)
+}
+
+function startSerializableTransaction (callback) {
+ console.log(db)
+ db.sequelize.transaction({ isolationLevel: 'SERIALIZABLE' }).asCallback(function (err, t) {
+ // We force to return only two parameters
+ return callback(err, t)
+ })
+}
+
+// ---------------------------------------------------------------------------
+
+module.exports = utils