[Logging] Mention #[AsMonologProcessor]

Author: alexandre-daubois

logging/processors.rst

@@ -164,6 +164,30 @@ If you use several handlers, you can also register a processor at the
 handler level or at the channel level instead of registering it globally
 (see the following sections).
 
+When registering a new processor, instead of adding the tag manually in your
+configuration files, you can take full advantage of the ``#[AsMonologProcessor]``
+attribute by using it one the processor class::
+
+    // src/Logger/SessionRequestProcessor.php
+    namespace App\Logger;
+
+    use Monolog\Attribute\AsMonologProcessor;
+    // ...
+
+    #[AsMonologProcessor]
+    class SessionRequestProcessor
+    {
+        // ...
+    }
+
+The ``#[AsMonologProcessor]`` attribute takes 3 optional arguments:
+
+* ``channel``: the logging channel the processor should be pushed to
+* ``handler``: the handler the processor should be pushed to
+* ``method``: the method that processes the records (if the attribute is used
+  at the class level). Indeed, the attribute can also be used directly
+  on a class method.
+
 Symfony's MonologBridge provides processors that can be registered inside your application.
 
 :class:`Symfony\\Bridge\\Monolog\\Processor\\DebugProcessor`