Merge pull request #1 from yohane55/transaction-hook

adding transaction hook

hooks/sequelize-transaction-hook.js

@@ -0,0 +1,65 @@
+/* eslint-disable require-atomic-updates */
+const start = (options = {}) => {
+  return async hook => {
+    if (
+      hook.params.transaction ||
+      (hook.params.sequelize && options.params.sequelize.transaction)
+    ) {
+      // already in transaction probably in diffrent hook or service
+      // so we dont create or commit the transaction in this service
+      return hook;
+    }
+
+    const sequelize = await hook.app.get("sequelizeClient");
+    const transaction = await sequelize.transaction();
+
+    hook.params.transaction = transaction;
+    hook.params.transactionOwner = hook.path;
+    hook.params.sequelize = hook.params.sequelize || {};
+    hook.params.sequelize.transaction = transaction;
+
+    return hook;
+  };
+};
+
+const end = () => {
+  return hook => {
+    const { params } = hook.params;
+    if (
+      !params ||
+      !params.transactionOwner ||
+      params.transactionOwner !== hook.path
+    ) {
+      // transaction probably from diffrent hook or service
+      // so we dont commit or rollback the transaction in this service
+      return hook;
+    }
+    const trx = params.sequelize.transacrion || params.transacrion;
+    return trx.then(t => t.commit()).then(() => hook);
+  };
+};
+
+const rollback = () => {
+  return hook => {
+    const { params } = hook.params;
+    if (
+      !params ||
+      !params.transactionOwner ||
+      params.transactionOwner !== hook.path
+    ) {
+      // transaction probably from diffrent hook or service
+      // so we dont commit or rollback the transaction in this service
+      return hook;
+    }
+    const trx = params.sequelize.transacrion || params.transacrion;
+    return trx.then(t => t.rollback()).then(() => hook);
+  };
+};
+
+module.exports = {
+  transaction: {
+    start,
+    end,
+    rollback
+  }
+};