More verbose file migration logging

See https://github.com/silverstripeltd/open-sourcerers/issues/91

* Add `PreformattedEchoHandler`

cherry-picked from 4c3f3e6bea99b46b689e5b23d1bd1498a4ac696c

* Batch log messages for every 100 file.
Also make logger work for stdout

* Update src/Logging/PreformattedEchoHandler.php

Co-Authored-By: bergice <bergice@users.noreply.github.com>

src/Dev/Tasks/MigrateFileTask.php

@@ -2,7 +2,13 @@
 
 namespace SilverStripe\Dev\Tasks;
 
+use Monolog\Handler\StreamHandler;
+use Monolog\Logger;
+use Psr\Log\LoggerInterface;
 use SilverStripe\AssetAdmin\Helper\ImageThumbnailHelper;
+use SilverStripe\Control\Director;
+use SilverStripe\Core\Injector\Injector;
+use SilverStripe\Logging\PreformattedEchoHandler;
 use SilverStripe\ORM\DB;
 use SilverStripe\Assets\FileMigrationHelper;
 use SilverStripe\Dev\BuildTask;
@@ -12,7 +18,6 @@ use SilverStripe\Dev\BuildTask;
  */
 class MigrateFileTask extends BuildTask
 {
-
     private static $segment = 'MigrateFileTask';
 
     protected $title = 'Migrate File dataobjects from 3.x';
@@ -23,6 +28,8 @@ class MigrateFileTask extends BuildTask
 
     public function run($request)
     {
+        $this->addLogHandlers();
+
         if (!class_exists(FileMigrationHelper::class)) {
             DB::alteration_message("No file migration helper detected", "notice");
             return;
@@ -46,4 +53,22 @@ class MigrateFileTask extends BuildTask
         }
         ImageThumbnailHelper::singleton()->run();
     }
+
+    /**
+     * TODO Refactor this whole mess into Symfony Console on a TaskRunner level,
+     * with a thin wrapper to show coloured console output via a browser:
+     * https://github.com/silverstripe/silverstripe-framework/issues/5542
+     * @throws \Exception
+     */
+    protected function addLogHandlers()
+    {
+        if ($logger = Injector::inst()->get(LoggerInterface::class)) {
+            if (Director::is_cli()) {
+                $logger->pushHandler(new StreamHandler('php://stdout'));
+                $logger->pushHandler(new StreamHandler('php://stderr', Logger::WARNING));
+            } else {
+                $logger->pushHandler(new PreformattedEchoHandler());
+            }
+        }
+    }
 }

src/Logging/PreformattedEchoHandler.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace SilverStripe\Logging;
+
+use Monolog\Handler\AbstractProcessingHandler;
+
+/**
+ * Echo the output as preformatted HTML, emulating console output in a browser.
+ * Tiding us over until we can properly decoupled web from CLI output.
+ * Do not use this API outside of core modules,
+ * it'll likely be removed as part of a larger refactor.
+ *
+ * See https://github.com/silverstripe/silverstripe-framework/issues/5542
+ *
+ * @internal
+ */
+class PreformattedEchoHandler extends AbstractProcessingHandler
+{
+
+    /**
+     * @param array $record
+     */
+    protected function write(array $record)
+    {
+        echo sprintf('<pre>%s</pre>', htmlspecialchars($record['formatted'], ENT_QUOTES, 'UTF-8'));
+    }
+}