Add simple_message module

config/sync/core.extension.yml

@@ -34,6 +34,7 @@ module:
   rdf: 0
   search: 0
   shortcut: 0
+  simple_message: 0
   system: 0
   taxonomy: 0
   text: 0

web/modules/custom/simple_message/simple_message.info.yml

@@ -0,0 +1,5 @@
+name: Simple Message
+description: Displays a simple message.
+core: 8.x
+type: module
+package: Custom

web/modules/custom/simple_message/simple_message.services.yml

@@ -0,0 +1,5 @@
+services:
+  Drupal\simple_message\DisplaySimpleMessage:
+    autowire: true
+    tags:
+      - { name: event_subscriber }

web/modules/custom/simple_message/src/DisplaySimpleMessage.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace Drupal\simple_message;
+
+use Drupal\Core\Messenger\MessengerInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+
+class DisplaySimpleMessage implements EventSubscriberInterface {
+
+  use StringTranslationTrait;
+
+  /**
+   * The Messenger service.
+   *
+   * @var \Drupal\Core\Messenger\MessengerInterface
+   */
+  private $messenger;
+
+  public function __construct(MessengerInterface $messenger) {
+    $this->messenger = $messenger;
+  }
+
+  public function displayMessage(GetResponseEvent $event) {
+    $this->messenger->addMessage($this->t('This site is running on a <a href="@vagrant">Vagrant</a> server, deployed with <a href="@ansible">Ansible</a> and <a href="@ansistrano">Ansistrano</a>.', [
+      '@ansible' => 'https://ansible.com',
+      '@ansistrano' => 'https://ansistrano.com',
+      '@vagrant' => 'https://vagrantup.com',
+    ]));
+  }
+
+  /**
+   * @inheritDoc
+   */
+  public static function getSubscribedEvents() {
+    $events[KernelEvents::REQUEST][] = ['displayMessage'];
+
+    return $events;
+  }
+
+}