在日志中显示当前用户

I'm trying to create a custom monolog processor to attach the current user to an error mailer.

When declaring a service like so:

monolog.processor.mail:
        class: MyVendor\Monolog\Processor\MailProcessor
        arguments:
            - @mailer
            - @security.context
        tags:
            - { name: monolog.processor, method: processRecord }

I get a circular reference:

[Symfony\Component\DependencyInjection\Exception\ServiceCircularReferenceException]
Circular reference detected for service "monolog.processor.mail",
path: "router -> monolog.logger.router -> monolog.processor.mail
-> security.context -> security.authentication.manager
-> fos_user.user_provider.username_email-> fos_user.user_manager
-> doctrine.orm.default_entity_manager -> doctrine.dbal.default_connection
-> doctrine.dbal.logger -> monolog.logger.doctrine".

What would be the best practice solution here?

This thread shows that:

Setter injection doesn't solve the issue (i tried this as well)
Injecting the container causes an infinitive recursion (this i have not confirmed)

Also tried this script http://pastebin.com/AuvFgTY3 to get the user from the session.

if ($this->session !== null) {
    if ($this->session->has($this->securityKey)) {
        $token = unserialize($this->session->get($this->securityKey));
        $this->currentUser = $token->getUser();
    }
}

This gave the following error:

Warning: ini_set(): A session is active. You cannot change the session module's ini settings at this time in
C:\inetpub\symfony23\vendor\symfony\symfony\src\Symfony\Component\HttpFoundation\Session\Storage\Handler\NativeFileSessionHandler.php
on line 56

I do understand that the security.context has not yet been build for services which request the logger very early on. For my class it's not a problem since i will set the user to undefined. So ideally the security.context would be setter injected AFTER the security.context service has been created. However i can not change the priority on the logger to be constructed very late because it's needed early on. So maybe the question resolves to: how to recreate the service again after security.context has been initialized? Not sure if scope prototype would help here??

Create handler on kernel request and extract user:

// src/AppBundle/Monolog/UserProcessor.php

namespace AppBundle\Monolog;

use Symfony\Component\HttpKernel\Event\GetResponseEvent;
use Symfony\Component\Security\Core\Authentication\Token\Storage\TokenStorageInterface;

class UserProcessor
{
    private $tokenStorage;
    private $user;

    public function __construct(TokenStorageInterface $tokenStorage)
    {
        $this->tokenStorage = $tokenStorage;
    }

    public function __invoke(array $record)
    {
        if (null !== $this->user) {
            $record['extra']['user'] = $this->user->getUsername();
        }

        return $record;
    }

    public function onKernelRequest(GetResponseEvent $event)
    {
        if (null === $token = $this->tokenStorage->getToken()) {
            return;
        }

        if (!is_object($user = $token->getUser())) {
            // e.g. anonymous authentication
            return;
        }

        $this->user = $user;
    }
}

# app/config/services.yml

services:
    monolog.processor.user:
    class: AppBundle\Monolog\UserProcessor
    arguments:  ["@security.token_storage"]
    tags:
        - { name: monolog.processor }
        - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }

Symfony Documentation has problem