Merge pull request #1777 from sequelize/forUpdate

Support for FOR UPDATE and FOR SHARE queries

lib/dialects/abstract/query-generator.js

@@ -956,6 +956,14 @@ module.exports = (function() {
         query = mainQueryItems.join('')
       }
 
+      if (options.lock && this._dialect.supports.lock) {
+        if (options.lock === 'SHARE') {
+          query += ' ' + this._dialect.supports.forShare
+        } else {
+          query += ' FOR UPDATE'
+        }
+      }
+
       query += ";";
 
       return query

lib/dialects/mysql/index.js

@@ -7,7 +7,9 @@ var MysqlDialect = function(sequelize) {
 
 MysqlDialect.prototype.supports = _.defaults({
   'VALUES ()': true,
-  'LIMIT ON UPDATE':true
+  'LIMIT ON UPDATE':true,
+  lock: true,
+  forShare: 'LOCK IN SHARE MODE'
 }, Abstract.prototype.supports)
 
 module.exports = MysqlDialect

lib/dialects/postgres/index.js

@@ -8,7 +8,9 @@ var PostgresDialect = function(sequelize) {
 PostgresDialect.prototype.supports = _.defaults({
   'RETURNING': true,
   'DEFAULT VALUES': true,
-  schemas: true
+  schemas: true,
+  lock: true,
+  forShare: 'FOR SHARE',
 }, Abstract.prototype.supports)
 
 module.exports = PostgresDialect

lib/model.js

@@ -643,6 +643,7 @@ module.exports = (function() {
    * @param  {Number}                    [options.offset]
    * @param  {Object}                    [queryOptions] Set the query options, e.g. raw, specifying that you want raw data instead of built Instances. See sequelize.query for options
    * @param  {Transaction}               [queryOptions.transaction]
+   * @param  {String}                    [queryOptions.lock] Lock the selected rows in either share or update mode. Possible options are transaction.LOCK.UPDATE and transaction.LOCK.SHARE
    *
    * @see    {Sequelize#query}
    * @return {Promise<Array<Instance>>}

lib/query-interface.js

@@ -552,6 +552,8 @@ module.exports = (function() {
       })
     }
 
+    options.lock = queryOptions.lock
+
     var sql = this.QueryGenerator.selectQuery(tableName, options, factory)
     queryOptions = Utils._.extend({}, queryOptions, {
       include: options.include,

lib/transaction.js

@@ -40,6 +40,26 @@ Transaction.ISOLATION_LEVELS = {
 }
 
 /**
+ * Possible options for row locking. Used in conjuction with `find` calls:
+ *
+ * ```js
+ * t1 // is a transaction
+ * Model.findAll({
+ *   where: ...
+ * }, {
+ *   transaction: t1,
+ *   lock: t1.LOCK.UPDATE,
+ *   lock: t1.LOCK.SHARE
+ * })
+ * ```
+ * @property LOCK
+ */
+Transaction.LOCK = Transaction.prototype.LOCK = {
+  UPDATE: 'UPDATE',
+  SHARE: 'SHARE'
+}
+
+/**
  * Commit the transaction
  * 
  * @return {this}

test/transaction.test.js

 var chai        = require('chai')
   , expect      = chai.expect
   , Support     = require(__dirname + '/support')
+  , dialect     = Support.getTestDialect()
   , Transaction = require(__dirname + '/../lib/transaction')
+  , sinon       = require('sinon')
+
 
 describe(Support.getTestDialectTeaser("Transaction"), function () {
   this.timeout(4000);
@@ -71,4 +74,120 @@ describe(Support.getTestDialectTeaser("Transaction"), function () {
       })
     })
   })
+
+  if (dialect !== 'sqlite') {
+    describe('row locking', function () {
+      this.timeout(10000);
+      it('supports for update', function (done) {
+        var User = this.sequelize.define('user', {
+              username: Support.Sequelize.STRING,
+              awesome: Support.Sequelize.BOOLEAN
+            })
+          , self = this
+          , t1Spy = sinon.spy()
+          , t2Spy = sinon.spy()
+
+        this.sequelize.sync({ force: true }).then(function () {
+          return User.create({ username: 'jan'})
+        }).then(function () {
+          self.sequelize.transaction(function (t1) {
+            return User.find({
+              where: {
+                username: 'jan'
+              }
+            }, { 
+              lock: t1.LOCK.UPDATE,
+              transaction: t1
+            }).then(function (t1Jan) {
+              self.sequelize.transaction({
+                isolationLevel: Transaction.ISOLATION_LEVELS.READ_COMMITTED
+              }, function (t2) {
+                User.find({
+                  where: {
+                    username: 'jan'
+                  },
+                }, { 
+                  lock: t2.LOCK.UPDATE, 
+                  transaction: t2
+                }).then(function () {
+                  t2Spy()
+                  t2.commit().then(function () {
+                    expect(t2Spy).to.have.been.calledAfter(t1Spy) // Find should not succeed before t1 has comitted
+                    done()
+                  })
+                })
+
+                t1Jan.updateAttributes({
+                  awesome: true
+                }, { transaction: t1}).then(function () {
+                  t1Spy()
+                  setTimeout(t1.commit.bind(t1), 2000)
+                })
+              })
+            })
+          })
+        })
+      })
+
+      it('supports for share', function (done) {
+        var User = this.sequelize.define('user', {
+              username: Support.Sequelize.STRING,
+              awesome: Support.Sequelize.BOOLEAN
+            })
+          , self = this
+          , t1Spy = sinon.spy()
+          , t2FindSpy = sinon.spy()
+          , t2UpdateSpy = sinon.spy()
+
+        this.sequelize.sync({ force: true }).then(function () {
+          return User.create({ username: 'jan'})
+        }).then(function () {
+          self.sequelize.transaction(function (t1) {
+            return User.find({
+              where: {
+                username: 'jan'
+              }
+            }, { 
+              lock: t1.LOCK.SHARE,
+              transaction: t1
+            }).then(function (t1Jan) {
+              self.sequelize.transaction({
+                isolationLevel: Transaction.ISOLATION_LEVELS.READ_COMMITTED
+              }, function (t2) {
+                User.find({
+                  where: {
+                    username: 'jan'
+                  }
+                }, { transaction: t2}).then(function (t2Jan) {
+                  t2FindSpy()
+
+                  t2Jan.updateAttributes({
+                    awesome: false
+                  }, { 
+                    transaction: t2
+                  }).then(function () {
+                    t2UpdateSpy()
+                    t2.commit().then(function () {
+                      expect(t2FindSpy).to.have.been.calledBefore(t1Spy) // The find call should have returned
+                      expect(t2UpdateSpy).to.have.been.calledAfter(t1Spy) // But the update call should not happen before the first transaction has committed
+                      done()
+                    })
+                  })
+                })
+
+                t1Jan.updateAttributes({
+                  awesome: true
+                }, {
+                  transaction: t1
+                }).then(function () {
+                  t1Spy()
+                  setTimeout(t1.commit.bind(t1), 2000)
+                })
+              })
+            })
+          })
+        })
+      })
+    })
+  }
 })