Add environment support

Author: mnapoli

README.md

@@ -68,3 +68,28 @@ puli.json
 ```
 
 When users install your package and tell the kernel to load the `blogpress` module, it will load all the files matching the Puli path `/blogpress/config/*.php` (i.e. `vendor/johndoe/blogpress/res/config/*.php` on the filesystem).
+
+### Environments
+
+Applications often need to behave differently according to the environment: `dev`, `prod`, etc.
+
+PHP-DI's Kernel let you write config for specific environments through a simple convention:
+
+```
+res/
+    config/
+        config.php
+        env/
+            dev.php
+            prod.php
+    ...
+```
+
+You can then instruct the environment to load:
+
+```php
+$kernel = new Kernel($modules, 'dev'); // dev environment
+$kernel = new Kernel($modules, 'prod'); // prod environment
+```
+
+Note that **environments are optional**.

src/Kernel.php

@@ -29,12 +29,19 @@ class Kernel
      */
     private $modules;
 
+    /**
+     * @var string
+     */
+    private $environment;
+
     /**
      * @param array $modules The name of the modules to load.
+     * @param string $environment Environment of the application (prod, dev, test, ...).
      */
-    public function __construct(array $modules = [])
+    public function __construct(array $modules = [], $environment = 'prod')
     {
         $this->modules = $modules;
+        $this->environment = $environment;
     }
 
     /**
@@ -112,5 +119,14 @@ private function loadModule(ContainerBuilder $builder, ResourceRepository $resou
                 $builder->addDefinitions($resource->getFilesystemPath());
             }
         }
+
+        // Load the environment-specific config if it exists
+        $envConfig = '/' . $module . '/config/env/' . $this->environment . '.php';
+        if ($resources->contains($envConfig)) {
+            $resource = $resources->get($envConfig);
+            if ($resource instanceof FilesystemResource) {
+                $builder->addDefinitions($resource->getFilesystemPath());
+            }
+        }
     }
 }

tests/KernelTest.php

@@ -58,7 +58,7 @@ public function registers_puli_discovery()
      */
     public function loads_module_configs()
     {
-        PuliFactoryClass::$repository->add('/blog/config/config.php', new FileResource(__DIR__.'/Fixture/config.php'));
+        PuliFactoryClass::$repository->add('/blog/config/config.php', new FileResource(__DIR__.'/test-module/config.php'));
 
         $this->kernel = new Kernel([
             'blog',
@@ -68,4 +68,21 @@ public function loads_module_configs()
 
         $this->assertEquals('bar', $container->get('foo'));
     }
+
+    /**
+     * @test
+     */
+    public function loads_module_environment_config()
+    {
+        PuliFactoryClass::$repository->add('/blog/config/config.php', new FileResource(__DIR__.'/test-module/config.php'));
+        PuliFactoryClass::$repository->add('/blog/config/env/dev.php', new FileResource(__DIR__.'/test-module/env/dev.php'));
+
+        $this->kernel = new Kernel([
+            'blog',
+        ], 'dev');
+        $this->kernel->setPuliFactoryClass(PuliFactoryClass::class);
+        $container = $this->kernel->createContainer();
+
+        $this->assertEquals('biz', $container->get('foo'));
+    }
 }

tests/Fixture/config.php renamed to tests/test-module/config.php

@@ -0,0 +1,5 @@
+<?php
+
+return [
+    'foo' => 'biz',
+];