Composer and Azure Websites Git Deployment

Continuing my series on PHP PaaS Clouds (Fortrabbit), I turn to Microsoft Azure today. After some research I found out Azure supports post deployment hooks to run Composer and allows you to configure environment variables from the Management console.

Microsoft launched Azure Websites in June this year. It is a platform as a service solution where you can deploy your websites via FTP or Git. With Azure Websites you can avoid having to deal with the complex deployment automation that is necessary for Azure Hosted Cloud Services. As long as your website only requires an SQLServer, MySQL or external APIs you can actually achieve quite a lot already.

For a Symfony2, Silex or any other modern project however you want Composer support during the deployment as long as failures with Composer don't break your site.

It turns out that Azure Websites - to support other platforms that require compiling - actually has an extremely robust deployment system (as far as I understood its internals). The Git repository is separated from the actual code that is served from the webserver and a number of old checkouts is kept to allow rollbacks through the Web interface. Once a Git push was recognized, Azure websites will execute a build step, and then copy all the files over to a directory with the name of the Git SHA hash. This directory is then symlinked to the document root.

If Composer fails during this step, the website will still be served from the currently running version and you don't have to face unexpected downtime.

To actually run Composer as a post-deployment tool you have to do some manual work. Create a .deployment file in your project root folder:

[config]
command = "D:\Program Files (x86)\PHP\v5.3\php.exe" build_azure.php

If you are using PHP 5.4, then you probably have to change the command version name to "v5.4", but I haven't tested this.

Then you need to create the build_azure.php file that is referenced in the deployment command. The actual implementation is up to you, my version is the most simple one:

<?php
if (!file_exists("composer.phar")) {
    $url = 'https://getcomposer.org/composer.phar';
    file_put_contents("composer.phar", file_get_contents($url));
}

$_SERVER['argv'][1] = "update";
$_SERVER['argv'][2] = "--prefer-dist";
$_SERVER['argv'][3] = "-v";
require "composer.phar";

Instead of using this approach, you could ship composer.phar with your repository for example. You can of course execute additional steps in the build_azure.php, for example warmup caches.