bug symfony#20610 [FrameworkBundle] Add framework.cache.prefix_seed for predictible cache key prefixes (nicolas-grekas)

This PR was merged into the 3.2 branch.

Discussion
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[FrameworkBundle] Add framework.cache.prefix_seed for predictible cache key prefixes

| Q             | A
| ------------- | ---
| Branch?       | 3.2
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

That's a design issue: using root_dir as discriminant doesn't work with blue/green deployment strategies, and doesn't prevent collision when different apps are deployed in the same path while sharing the same cache backend.

Commits
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82952bd [FrameworkBundle] Add framework.cache.prefix_seed for predictible cache key prefixes

Author: fabpot

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Compiler/CachePoolPass.php

@@ -31,11 +31,12 @@ public function process(ContainerBuilder $container)
     {
         $namespaceSuffix = '';
 
-        foreach (array('name', 'root_dir', 'environment', 'debug') as $key) {
-            if ($container->hasParameter('kernel.'.$key)) {
-                $namespaceSuffix .= '.'.$container->getParameter('kernel.'.$key);
+        foreach (array('kernel.name', 'kernel.environment', 'kernel.debug', 'cache.prefix.seed') as $key) {
+            if ($container->hasParameter($key)) {
+                $namespaceSuffix .= '.'.$container->getParameter($key);
             }
         }
+        $container->getParameterBag()->remove('cache.prefix.seed');
 
         $aliases = $container->getAliases();
         $attributes = array(

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php

@@ -667,6 +667,10 @@ private function addCacheSection(ArrayNodeDefinition $rootNode)
                     ->addDefaultsIfNotSet()
                     ->fixXmlConfig('pool')
                     ->children()
+                        ->scalarNode('prefix_seed')
+                            ->info('Used to namespace cache keys when using several apps with the same shared backend')
+                            ->example('my-application-name')
+                        ->end()
                         ->scalarNode('app')
                             ->info('App related cache pools configuration')
                             ->defaultValue('cache.adapter.filesystem')

src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php

@@ -1242,6 +1242,9 @@ private function registerCacheConfiguration(array $config, ContainerBuilder $con
         $container->getDefinition('cache.adapter.system')->replaceArgument(2, $version);
         $container->getDefinition('cache.adapter.filesystem')->replaceArgument(2, $config['directory']);
 
+        if (isset($config['prefix_seed'])) {
+            $container->setParameter('cache.prefix.seed', $config['prefix_seed']);
+        }
         foreach (array('doctrine', 'psr6', 'redis') as $name) {
             if (isset($config[$name = 'default_'.$name.'_provider'])) {
                 $container->setAlias('cache.'.$name, Compiler\CachePoolPass::getServiceProvider($container, $config[$name]));