Download the PHP package inneair/transaction-bundle without Composer

Inneair Transaction bundle for Symfony

This bundle provides an easy way to manage transactions with annotations. It is highly inspired from the one provided as example by the JMSAopBundle, but provides :

• a configurable policy, allowing a class/method to choose whereas a new transaction must/shall be opened, or must not exist at all.
• an inheritance of the transactional context, from an annotated class/method to an other.
• a configurable list of exceptions that shall not trigger a rollback when a method call completes with an exception.

Why use this bundle instead of the standard behaviour of the Doctrine-ORM's entity manager?

If you dig into the code of the Doctrine-ORM's entity manager, we can see the entity manager already supports recursive calls of the method begin_transaction, and starts really a transaction for the top call. However, it means this behaviour - consisting of determining if a transaction shall be opened - is coded in the persistence layer. Transactions shall be managed by business components, who are able to state what's the expected behaviour. The ORM is part of the persistence layer, and shall not be aware of this.

Summary

• Installation
• Configuration
• Usage
• Example

Installation

1. Download

The bundle can be installed in your Symfony project with Composer. Open a command console, enter your project directory and execute the following command to download the latest stable version of this bundle:

2. Activation

Activate the JMSAopBundle first, following those instructions for installation and configuration.

Activate the bundle by modifying the app/AppKernel.php file:

Configuration

1. YAML configuration

2. XML configuration

3. Reference

strict_mode: whether classes must implement the TransactionalAwareInterface interface, so as the annotation @Transactional is read. Default is false.

default_policy: default transactional policy when none policy is set in the annotation, which must be one of these values:

• required: a transaction must be started if no transactional context already exist.
• not-required: a transaction must not be started, whatever there is an existing transaction context.
• nested: a new transaction (use of save points) must be started, even if there is already a transactional context. Save points must be enabled in the connection parameters (see the DoctrineBundle configuration reference). However, we strongly recommend to avoid the use of nested transactions. Components shall be designed to use the required or not-required strategies.

Default is required.

no_rollback_exceptions: array of full qualified class names of exceptions, for which rollback won't be triggered if a transactional context is alive. Use of this parameter shall be exceptional. Default is the empty array.

Usage

Inside any container-managed component, insert the annotation @Transaction to enable automatic transaction management. When a parameter is defined in the annotation, it overwrites the default value in the bundle configuration.

WARNING: keep separated concerns, and decoupled components. Transaction management in controllers, though frequently shown in examples, is not a good design orientation. Controllers in web applications are HTTP interfaces, and their role is basically to receive requests, call business services, return responses: by definition, they belong to the presentation layer. Transactions shall be managed by business components only.

1. Whole service

The annotation can be inserted in the PHP doc block of the class itself, allowing transaction management for all public methods. All annotation parameters are optional. If none is specified, the default configuration of the bundle applies (see above).

2. Single method

The annotation can be inserted in the PHP doc block of a public method itself, to allow transaction management. The annotation parameters are optional. If none is specified, the default configuration of the bundle applies (see above).

A concrete example

Let's imagine an application dealing with human resources, and organization of people among many companies. A good strategy (among other ones) would be to implement:

• a business service for the management of companies CompanyManager.
• a business service for the management of people in these companies PersonManager.

Let's focus on the user story: "I want to register a new person in a new company (in one step)".

1. The Company model

The company is at the top of our business model, it is standalone (no dependencies).

2. The Person model

The person is also a very simple concept, but in our application, a person always belongs to a company. Therefore, the model shall contain a dependency.

3. The CompanyManager service

When another component (let's say an HTTP controller) needs to add a new company, this must be done in an atomic, consistent, isolated, and durable way (ACID principles...). A transaction is an appropriate solution! Using the @Transactional annotation, each time a component calls addCompany method, a new transaction context will be opened. If something goes bad in this method (an exception for instance), every operation already done in the persistence layer is automatically rolled back, and the system remains in a consistent state. Otherwise, the transaction is committed.

4. The PersonManager service

When another component (let's say an HTTP controller) needs to add a new person in a new company, this must also be done in an atomic, consistent, isolated, and durable way (ACID principles...). If the company is created, and the person can not be created, we want all operations to be rolled back. A transaction is also needed, so let's add the @Transactional annotation for the addPerson method.

At this point, you may remark two transactions are opened:

• a first one when the addPerson is called,
• a second one when the addCompany is called inside the addPerson method.

In fact, absolutely not, and this is why this bundle really helps. With the default required policy, we actually specify we want a transaction to be opened only if there is not an active transactional context. Then, a new transaction is not opened when the addCompany is called within the transactional context of the addPerson method. The transactional context is automatically inherited. On the other hand, if the addCompany is called outside a transactional context, a new transaction is opened.

Using the @Transactional annotation is a key factor to design reliable business services, with a low coding effort.