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CakePHP Migrations plugin: easily version and deploy whole applications

This article is a quick introduction to the Migrations plugin, open sourced a few weeks ago by our company. You will see how simple it is to use the plugin and what you could do with it. I hope this article will show you the benefits of using migrations in your CakePHP applications and make you give it a try right after the reading!

Here is a one-sentence description of the plugin: the Migrations plugin allows developers to easily version and automate the creation / update process of any database schema and application data from the command line.

For information, CakeDC uses this plugin on its project since several years to make team collaboration and deployment easier. The plugin has been entirely rewritten a few months ago and fully tested (code coverage >95% as always at CakeDC) before being open sourced under the MIT license. It is now available to the community along with its documentation... and it is free!

Why is it useful?

It has been a while since companies integrated Source Code Management in their development process and CVS, SVN, Mercurial or Git are now common tools. Inspired from the open source movement it is also a good practice for single developers to version application source code.

As you might know, an application almost always depends of the database schema it is aimed to use... however it is not easy to version both the source code and database schema with a SCM. Let's take the example of a CakePHP application: until now the only way to do was to version a single file, either a sql dump or a CakePHP schema.php file generated with the cake schema shell. These two approaches are not very convenient to use on a daily basis, the first one forcing the developer to drop and recreate the whole database every time!

Moreover, a web application development is never really finished (there are always new features to add, software updates or bug fixing to do...) and deploying these change on a test or production server is always a delicate task.

Here comes the Migrations plugin! It provides a simple and easy way to version a database... and to perform many other different tasks thanks to its callback system. Here are some features:

  • keep a local database schema up-to-date: you just have to run all non applied migrations to update the local database schema to the latest version
  • make team work easier: when several developers work on the same application it is important that all of them work with the same database schema during all the development cycle. With migrations every commit is tied to the database schema at this precise instant, which makes easy switching branches and resetting a branch to a specific commit.
  • make installation and updates easier: ready to push the new version of your application live? You will only have to push the sources on the server and run all non applied migrations!
  • migrate more than database schema: the callback system allows you to do everything you want before (or after) applying (or reverting) each migration. Here are some examples: creating an initial admin account, add initial or test data to the application (lorem ipsums, categories, content...), update values from the database, send an email if debug > 0... The only limit may be your imagination ;)

Where can I find the code?

Announced a few weeks ago, a packaged version of the plugin can be downloaded from the "Plugins" section of CakeDC.com. This page contains a link to download the 1.0 version, the plugin documentation and the Github project for tickets and direct Git access to the repository.

To make people aware of the need to show their support to the Cake Software Fundation by donating a few bucks (this is unfortunately not done enough), the plugin was first available to donors only. The "Download without donation" button was added later, when the repository was made public! However, if you find this plugin useful please consider making a donation to the CSF... that is the best thing you could do for thanking us.

Even better! A sample application was also released for those who want to see how migrations could be used and integrated in an application. To play with it, Download the code or git clone the project using:

git clone git://codaset.com/cakedc/sample-migrations-application.git sample_migrations

You will only need to create a database.php configuration file and update CakePHP's core location to make the application work. Git users, run

git submodule init
git submodule update

to automatically add the migrations plugin as a submodule!

What do I need to use it in my application?

Note: the packaged plugin is for the CakePHP 1.3 version only. You can either download the 1.3-beta package of the framework, or use the 1.2 branch available in the Git repository.

Adding the plugin to an existing application is very simple. If you downloaded the archive containing the plugin code, unzip it in the "/plugins/migrations" folder of your application. Git users can add it as a submodule with the following command:

git submodule add git://codaset.com/cakedc/migrations.git plugins/migrations

To check that it is installed correctly, execute the following command from your application root (it will display the available command to use the plugin):

cake migration help

If you encounter any problem here, please read the official documentation about CakePHP's console usage.

How does it work?

This post is not aimed at providing a comprehensive tutorial on how to use the plugin, thus I will just introduce the most useful commands along with some use cases.

For a complete documentation, please read the official documentation provided on the plugin page. For a simple (but useful for understanding purpose) use case you can take a look at the sample application introduced above. Going through the commit history will allow you to understand how migrations could be used in a development process.

Create a migration

To generate a new migration, type the following command

cake migration generate

The tool will ask you to give a name to the migration and suggest to do a dump of the current database schema. If a "schema.php" file is found in the application, it will ask you if you want to generate a diff between this schema and your current database one.

Generated migration files will be added to the "/config/migrations" application directory.

Apply / Revert migrations

When you pull an application containing migrations, several commands are available to apply or revert migrations. The simplest one is:

cake migration

It will display all the found migrations along with their status (applied or not applied) and id number. Just enter a migration number to update your database to the correct version. Some convenience commands are also available. You can use:

cake migration up, down, all or reset

These commands will respectively:

  • apply the next migration
  • revert the latest applied migration
  • apply all non applied migrations (and thus update the schema to the most recent version)
  • revert all applied migrations (and empty the database)

Migrations for plugins

Adding plugins to an existing application often implies adding new tables to the database or altering existing ones. The Migrations plugin brings a quick and efficient way to automate this installation. On the one hand developers can easily add necessary migrations to their plugin (making upgrades easier), on the other hand users can apply them as easily.

The only difference compared with commands introduced above is the parameter "-plugin pluginname" that needs to be added. Here is how the user will install the database for the newly added / updated plugin "test":

cake migration run all -plugin test

I would like to highlight the fact that callbacks allow the developer to do everything they want before / after each migration. It is convenient for adding initial data, and one can even implement a callback method opening the bootstrap.php file to append plugin's configuration entries there (it is just an example ;)).

... going further

Of course, feel free to add any remark or example of migrations use in the comments.

As this post is not aimed at providing support for the plugin, I recommend you to use the official tools available:

  • If you found a bug or want to suggest enhancements: open a ticket!
  • An installation problem or a question about the plugin usage? Ask your question to the community!
  • You would like a custom version of this plugin, or professional related services... contact us, it is our job ;)

I hope you enjoyed this post, it is now time for you to start playing with the Migrations plugin...

Latest articles

Dependency Injection with CakePHP

Let’s talk about Dependency Injection!

SOLID principles

As you know SOLID is an acronym for the  five object-oriented design principles. In this topic, we will focus on Interface segregation principle and Dependency inversion principle. Interface segregation principle states that a client must not be forced to implement an interface that they do not use, or clients shouldn’t be forced to depend on methods they do not use. In other words, having  many client-specific interfaces is better than one general-purpose interface. From the other side, Dependency inversion principle states that objects must depend on abstractions, not on concretions. It states that the high-level module must not depend on the low-level module, but they should depend on abstractions. To follow Dependency inversion principle, we need to construct low-level modules and pass them to constructors, and that might create a lot of manual work for developers. The dependency injection container is created specifically for solving the problem with manual construction of an object, before creating a specific object. If we follow interface segregation principle when developing application modules, it would be easy to configure a container and switch module dependency. This is where the interface shows its incredible power.  

Few words about CakePHP Events System

CakePHP Events System was created to allow injecting some logic using listeners. However, in some cases, it is used to get results from code that will be created by the module user. When an event is dispatched by the listener, it can return the result. Callback injection through the event system has some drawbacks. First of all, parameters passed to the event need to pass as a hash array. So unfortunately, there is no way to check that all params are really passed or to be sure that all passed params have correct types. Is there a way to solve this problem? Yes, and containers could help with that. Instead of passing events, we can get the required object from the container and call it method. But you could say: wait, we don't know what object could be used in client code within the developed plugin. That's fine, and this  is where interface segregation principle can help. In our plugin, we define an interface for each such case, and instead of dispatching an event, we can easily get an object from the container by interface.       $updater = $container->get(AfterLoginInterface::class);     if ($updater !== null) {         $user = $updater->afterLogin($user);     }   In the Application::services method, users link the interface with the specific class.       public function services(ContainerInterface $container): void     {         $container->add(AfterLoginInterface::class, MyAfterLogin::class);     }   In some of default behavior needed we can map service class for container to default implementation using Plugin::services method.       public function services(ContainerInterface $container): void     {         if (!$container->has(AfterLoginInterface::class)) {             $container->add(AfterLoginInterface::class, NullAfterLogin::class);         }     }  

Container propagation

Dependency injection is an experimental feature. Initial implementation limited by Controllers constructors and methods, and Commands constructors. If we want to access the container in other parts of the application, we may want to propagate it from app level. The most logical way would be to implement middleware and store the container inside the request attribute.   <?php declare(strict_types=1);   namespace App\Middleware;   use Cake\Core\ContainerInterface; use Psr\Http\Message\ResponseInterface; use Psr\Http\Message\ServerRequestInterface; use Psr\Http\Server\MiddlewareInterface; use Psr\Http\Server\RequestHandlerInterface; use RuntimeException;   /**  * Container Injector Middleware  */ class ContainerInjectorMiddleware implements MiddlewareInterface {     /**      * @var \Cake\Core\ContainerInterface      */     protected $container;       /**      * Constructor      *      * @param \Cake\Core\ContainerInterface $container The container to build controllers with.      */     public function __construct(ContainerInterface $container)     {         $this->container = $container;     }       /**      * Serve assets if the path matches one.      *      * @param \Psr\Http\Message\ServerRequestInterface $request The request.      * @param \Psr\Http\Server\RequestHandlerInterface $handler The request handler.      * @return \Psr\Http\Message\ResponseInterface A response.      */     public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface     {         return $handler->handle($request->withAttribute('container', $this->container));     }   That’s it! I hope that this will help you when you are baking with dependency injections. If you run into any problems, there are many support channels that allow the CakePHP community to help  You can check them out under the community tab at CakePHP.org.

One CakePHP Project Per Day

The whole team here at CakeDC are big supporters and contributors of the CakePHP community. For this month, I decided to do “one CakePHP project per day” to share with the community.  Here are some of my projects so far:

Project 01 - Notes App

A one page note application using CakePHP 4 and Bootstrap 5. This project is  a good starting point to learn the framework. Link: https://github.com/rochamarcelo/one-project-a-day-challenge-01-notes  

Project 02 - Contact List

An application to manage contacts - you are able to list, add, edit and delete contacts, upload contact avatar images or use avatar images from gravatar.com . It was built using CakePHP 4, plugin friendsofcake/search, plugin josegonzalez/cakephp-upload, Gravatar, and Bootstrap 5.  Link: https://github.com/rochamarcelo/one-project-a-day-challenge-02-contact-list  

Project 03 - Recipe Box

An application to manage recipes, using CakePHP 4,  CouchDB and Bootstrap 5. This one is a good starting point to learn to use CouchDB with CakePHP, including how to list, add and edit recipes (documents). Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-03-recipe-box  

Project 04 - Service Plan with Exchange rate

An application to list services and apply exchange rate using the api https://exchangeratesapi.io/documentation/ and CakePHP 4. In this one you see the custom namespace WebService to handle logic related to api as client. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-04-service-plans-ex-rate  

Project 05 - Polls

A fun poll app, using the awesome Bulma CSS Framework and CakePHP 4. A good example of model association and the CounterCache Behavior. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-05-polls-emmy  

Project 06 - Movie Theater Schedule

An application to see which movies are in the theaters and which hours by screen each day of the week. A good example of complex queries, model associations and seed data. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-06-movie-theater-schedule  

Project 07 - Podcast Finder

An application to help easily find podcasts and download episodes. In the source code you’ll find how to use the itunes api,  a structure to handle Model actions (that I think is a good option to make your models cleaner), and a way to parse podcasts feed (XML); example usage of dependency injection. The application was built with CakePHP 4 and Bulma CSS Framework. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-07-podcast-finder  

Project 08 - Url Shortener

An application to create short urls - a good example of how to create custom routes and use custom primary key types for a model. The application was built with CakePHP 4. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-08-url-shortener  

Project 09 - Quiz

Users can list quizzes, create quizzes and answer at any time. A good example of how to use MongoDB with CakePHP 4 with a base structure for Collection classes.  Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-09-quiz  

Project 10 - File Transfer

An application to easily send files to anyone, create an account, upload the file and inform the person email to send to. Built with CakePHP 4, plugin CakeDC/Users,  plugin Josegonzalez/Upload,  plugin friendsofcake/bootstrap-ui, SMTP and Bootstrap. A good example to see the usage of these plugins. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-10-file-transfer  

Project 11 - Tasks

A one page application for  users to manage their tasks. The user can create and remove decks, create and complete tasks, and list tasks grouped by decks. Built with CakePHP 4, plugin CakeDC/Users and Bootstrap 5 Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-11-tasks  

Project 12 - Blog

A blog website with blog posts and tags management, WYSIWYG editor, blog search, tags filtering. Built with CakePHP 4, CakeDC/Users plugin, friendsofcake/bootstrap-ui, Muffin/Slug, friendsofcake/search and Bootstrap 4 . A good example of usage of custom routes, route prefix, finders and multiple plugins. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-12-blog  

Project 13 - Olympic Medal Count

Perfect time for this project, right?! An application to display olympic medal count by country and sports. The source code uses CouterCache behavior and aggregated query. Built with CakePHP 4 and Bootstrap 5. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-13-olympic-medal-count
 

Project 14 - Smart Home Dashboard

An awesome dashboard to manage smart devices using MQTT Messaging, CakePHP 4, CakeDC/Users plugin, php-mqtt/client (testing with Mosquitto Broker) and Bootstrap 5. The application is able to publish messages to change device status and subscribe for status changes. Link: https://github.com/rochamarcelo/one-cakephp-project-a-day-challenge-14-smart-home-dashboard-mqtt    I hope that this initiative will somehow inspire others to put their Cake skills to work, and share their projects with the community. If you’d like to see my future projects and posts, you can follow me on Twitter, and I will share them all there! https://twitter.com/mrcodex

Logging CakePHP Applications To Team Communication

The log of applications is gold. It's an important part of the software, they represent the health of the application. By default, CakePHP will use the FileLog adapter which will write to /logs/ folder. It's hard to track the live issues, and by hard I mean you will need to connect to the server, open the file on /logs/ and look at the issue which you want to investigate.   What do you think if your application sends the error directly to your team communication (Slack, Teams, RocketChat) application? Will be easier to know about a new error after some deployment? This error is sneaky, and can be in command applications. Often, we only look at the errors when the users report it.   For this sample I will use Slack, but this approach can be implemented for any application.  All we need is to create a Log adapter and configure it. So…let’s bake that:     Now we may get errors like this:   That’s all bakers! I hope this article can be useful and you can improve your logs.  

We Bake with CakePHP