adding a custom method to define the priority of services

pcabreus · web-flow · commit 3b328b8252bc · 2019-06-21T00:36:40.000+02:00
This documents symfony/symfony#31943 about adding a custom method to define the priority of services
diff --git a/service_container/tags.rst b/service_container/tags.rst
@@ -562,3 +562,55 @@ application handlers::
                 ->addTag('app.handler', ['priority' => 20]);
 
     Note that any other custom attributes will be ignored by this feature.
+
+You can also prioritized services implementing a static method for it.
+The name of the method must be defined on the handler collection service:
+
+.. configuration-block::
+
+    .. code-block:: yaml
+
+        # config/services.yaml
+        services:
+            App\HandlerCollection:
+                # inject all services tagged with app.handler and ordered by the result of the getDefaultPriority
+                arguments: [!tagged { key: 'app.handler', default_priority_method: 'getDefaultPriority']
+
+    .. code-block:: xml
+
+        <!-- config/services.xml -->
+        <?xml version="1.0" encoding="UTF-8" ?>
+        <container xmlns="http://symfony.com/schema/dic/services"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xsi:schemaLocation="http://symfony.com/schema/dic/services
+                https://symfony.com/schema/dic/services/services-1.0.xsd">
+
+            <services>
+                <service id="App\HandlerCollection">
+                    <!-- inject all services tagged with app.handler and ordered by the result of the getDefaultPriority-->
+                    <argument type="tagged" tag="app.handler" default-priority-method="getDefaultPriority"/>
+                </service>
+            </services>
+        </container>
+
+    .. code-block:: php
+
+        // config/services.php
+        use Symfony\Component\DependencyInjection\Argument\TaggedIteratorArgument;
+
+        $container->register(App\HandlerCollection::class)
+            // inject all services tagged with app.handler as first argument
+            ->addArgument(new TaggedIteratorArgument('app.handler', null, null, false, 'getDefaultPriority'));
+
+Now you can define the priority on the service class::
+
+    // src/Handler/One.php
+    namespace App\Handler;
+
+    class One
+    {
+        public static function getDefaultPriorityMethod(): int
+        {
+            return 10;
+        }
+    }
