1 files changed, 69 insertions, 0 deletions

diff --git a/server/helpers/database-utils.ts b/server/helpers/database-utils.ts
new file mode 100644
index 000000000..b842ab9ec
--- /dev/null
+++ b/server/helpers/database-utils.ts
@@ -0,0 +1,69 @@
+// TODO: import from ES6 when retry typing file will include errorFilter function
+import retry = require('async/retry')
+
+const db = require('../initializers/database')
+import { logger } from './logger'
+
+function commitTransaction (t, callback) {
+  return t.commit().asCallback(callback)
+}
+
+function rollbackTransaction (err, t, callback) {
+  // Try to rollback transaction
+  if (t) {
+    // Do not catch err, report the original one
+    t.rollback().asCallback(function () {
+      return callback(err)
+    })
+  } else {
+    return callback(err)
+  }
+}
+
+// { arguments, errorMessage }
+function retryTransactionWrapper (functionToRetry, options, finalCallback) {
+  const args = options.arguments ? options.arguments : []
+
+  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) {
+  db.sequelize.transaction({ isolationLevel: 'SERIALIZABLE' }).asCallback(function (err, t) {
+    // We force to return only two parameters
+    return callback(err, t)
+  })
+}
+
+// ---------------------------------------------------------------------------
+
+export {
+  commitTransaction,
+  retryTransactionWrapper,
+  rollbackTransaction,
+  startSerializableTransaction,
+  transactionRetryer
+}