Add --refresh-content-version-only option to deploy

With this option you can quickly force a browser cache refresh or
a CDN cache refresh without having to generate all static content.

This comes in handy especially when you have made no code changes,
but the CDN failed to update it's cache the last time you deployed
or when you have made a manual change in one of the static files
as a hotfix on your deployment server, awaiting a suitable moment
for deployment to finalize it.

This reopens #9338.

Author: Anton Evers

app/code/Magento/Deploy/Console/DeployStaticOptions.php

@@ -131,6 +131,11 @@ class DeployStaticOptions
      */
     const CONTENT_VERSION = 'content-version';
 
+    /**
+     * Key for refresh content version only mode
+     */
+    const REFRESH_CONTENT_VERSION_ONLY = 'refresh-content-version-only';
+
     /**
      * Deploy static command options list
      *
@@ -225,6 +230,13 @@ private function getBasicOptions()
                 'Custom version of static content can be used if running deployment on multiple nodes '
                 . 'to ensure that static content version is identical and caching works properly.'
             ),
+            new InputOption(
+                self::REFRESH_CONTENT_VERSION_ONLY,
+                null,
+                InputOption::VALUE_NONE,
+                'Refreshing the version of static content only can be used to refresh static content '
+                . 'in browser cache and CDN cache.'
+            ),
             new InputArgument(
                 self::LANGUAGES_ARGUMENT,
                 InputArgument::IS_ARRAY,

app/code/Magento/Deploy/Service/DeployStaticContent.php

@@ -75,6 +75,16 @@ public function __construct(
      */
     public function deploy(array $options)
     {
+        $version = !empty($options[Options::CONTENT_VERSION]) && is_string($options[Options::CONTENT_VERSION])
+            ? $options[Options::CONTENT_VERSION]
+            : (new \DateTime())->getTimestamp();
+        $this->versionStorage->save($version);
+
+        if ($options[Options::REFRESH_CONTENT_VERSION_ONLY]) {
+            $this->logger->warning(PHP_EOL . "New content version: " . $version);
+            return;
+        }
+
         $queue = $this->queueFactory->create(
             [
                 'logger' => $this->logger,
@@ -96,11 +106,6 @@ public function deploy(array $options)
             ]
         );
 
-        $version = !empty($options[Options::CONTENT_VERSION]) && is_string($options[Options::CONTENT_VERSION])
-            ? $options[Options::CONTENT_VERSION]
-            : (new \DateTime())->getTimestamp();
-        $this->versionStorage->save($version);
-
         $packages = $deployStrategy->deploy($options);
 
         if ($options[Options::NO_JAVASCRIPT] !== true) {