caxy/appengine-bridge

Components to support Symfony components in Google App Engine

Google App Engine Bridge

This package supports Symfony and related components on Google App Engine., _(*1)

Features

• Monolog handler specifically for App Engine's simple syslog() facility.
• Pimple service provider for running Silex on App Engine.
• Abstract kernel base class that sets cache and log directories for App Engine.
• This README.

Installation

Add to composer.json:, _(*2)

{
    "repositories": [
        {
            "type": "vcs",
            "url": "https://github.com/caxy/AppEngineBridge.git"
        }
    ],
    "require": {
        "caxy/appengine-bridge": "~1.0@dev"
    }
}

Silex

Register the AppEngineProvider after your other providers have been registered., _(*3)

<?php
$app->register(new \Caxy\AppEngine\Bridge\Pimple\Provider\AppEngineProvider());

Make sure that the php55 runtime is set in your app.yaml or else Silex will fail because tempnam() support is only in php55., _(*4)

Symfony

Use the Google App Engine configuration file app.yaml to set environment variables. Using the php55 runtime is required. The SYMFONY__APP_ENGINE__DEFAULT_BUCKET_NAME value becomes a container parameter and is used to set up cache and log directories. Here is a work-in-progress example:, _(*5)

application: SOMETHING
version: 1
runtime: php55
api_version: 1
threadsafe: true

handlers:
- url: /bundles
  static_dir: web/bundles
- url: .*
  script: web/app.php

skip_files:
- ^(.*/)?#.*#$
- ^(.*/)?.*~$
- ^(.*/)?.*\.py[co]$
- ^(.*/)?.*/RCS/.*$
- ^(.*/)?\..*$
- ^(.*/)?.*/Tests/.*$
- var/cache/*
- var/logs/*

env_variables:
  SYMFONY_ENV: prod
  SYMFONY_DEBUG: 0
  SYMFONY__APP_ENGINE__DEFAULT_BUCKET_NAME: 'SOMETHING.appspot.com'

Replace your front controller entirely so you can switch between environments using the app.yaml environment variable. The example here is a combination of Symfony framework Standard Edition's app.php and app_dev.php., _(*6)

<?php

use Symfony\Component\ClassLoader\ApcClassLoader;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Debug\Debug;

$loader = require_once __DIR__.'/../var/bootstrap.php.cache';
if ((bool) $_SERVER['SYMFONY_DEBUG']) {
    Debug::enable();
}

// Enable APC for autoloading to improve performance.
// You should change the ApcClassLoader first argument to a unique prefix
// in order to prevent cache key conflicts with other applications
// also using APC.
/*
$apcLoader = new ApcClassLoader(sha1(__FILE__), $loader);
$loader->unregister();
$apcLoader->register(true);
*/

require_once __DIR__.'/../app/AppKernel.php';
//require_once __DIR__.'/../app/AppCache.php';

$kernel = new AppKernel($_SERVER['SYMFONY_ENV'], (bool) $_SERVER['SYMFONY_DEBUG']);
$kernel->loadClassCache();
//$kernel = new AppCache($kernel);

// When using the HttpCache, you need to call the method in your front controller instead of relying on the configuration parameter
//Request::enableHttpMethodParameterOverride();
$request = Request::createFromGlobals();
$response = $kernel->handle($request);
$response->send();
$kernel->terminate($request, $response);

Replace the Kernel that your AppKernel extends., _(*7)

diff --git a/app/AppKernel.php b/app/AppKernel.php
index 7673684..0d03d5a 100644
--- a/app/AppKernel.php
+++ b/app/AppKernel.php
@@ -1,6 +1,6 @@
 <?php

-use Symfony\Component\HttpKernel\Kernel;
+use Caxy\AppEngine\Bridge\HttpKernel\Kernel;
 use Symfony\Component\Config\Loader\LoaderInterface;

 class AppKernel extends Kernel

Establish memcache session handler. In app/config/services.yml:, _(*8)

services:
    session.memcache:
        class: Memcache

    session.handler.memcache:
        class:     Symfony\Component\HttpFoundation\Session\Storage\Handler\MemcacheSessionHandler
        arguments: [ @session.memcache ]

The Symfony profiler can store data in Memcached too. The specific host and port of this DSN are not important as GAE supplies its own PHP Memcache object., _(*9)

framework:
    profiler:
        dsn: 'memcache://localhost:11211'

Use the syslog Monolog handler. The ident value is unimportant but required for Symfony to instantiate the handler:, _(*10)

monolog:
    handlers:
        main:
            type:         fingers_crossed
            action_level: debug
            handler:      syslog
        syslog:
            type: syslog
            ident: whatever

Features to do

• Easily purge Symfony cache on GAE.
• Build the application without developer dependencies prior to updating.

Other Niceties

In your composer.json add a new scripts entry so that you can deploy easily from composer., _(*11)

{
    "scripts": {
        "appengine-update": [
             "appcfg.py update . --oauth2"
        ]
    }
}

Now you can deploy with the command composer appengine-update. Additional commands can be stacked together., _(*12)

{
    "scripts": {
        "appengine-update": [
             "composer dumpautoload -o",
             "appcfg.py update . --oauth2"
        ]
    }
}