Better fix for #6978 Keep logging in configured backends (e.g. file) and no additional class

core/Log/WebCronArchiveLogger.php

-<?php
-
-namespace Piwik\Log;
-
-use Monolog\Logger;
-use Psr\Log\AbstractLogger;
-use Psr\Log\LoggerInterface;
-
-/**
- * Basic logger that streams messages to stdout.
- *
- * This logger is used in the archiving when archive.php is called from a HTTP request. In that specific case,
- * we want to log to stdout.
- *
- * @see misc/cron/archive.php
- */
-class WebCronArchiveLogger extends AbstractLogger implements LoggerInterface
-{
-    public function log($level, $message, array $context = array())
-    {
-        if ($level <= Logger::DEBUG) {
-            return;
-        }
-        echo $message . "\n";
-    }
-}

misc/cron/archive.php

@@ -9,6 +9,8 @@
  * @package Piwik
  */
 
+use Monolog\Handler\StreamHandler;
+use Monolog\Logger;
 use Piwik\Container\StaticContainer;
 use Piwik\Log\WebCronArchiveLogger;
 use Symfony\Bridge\Monolog\Handler\ConsoleHandler;
@@ -65,11 +67,15 @@ if (isset($_SERVER['argv']) && Piwik\Console::isSupported()) {
         // just like for CLI
         StaticContainer::setEnvironment('cli');
         /** @var ConsoleHandler $consoleLogHandler */
-        $consoleLogHandler = StaticContainer::getContainer()->get('Symfony\Bridge\Monolog\Handler\ConsoleHandler');
+        $consoleLogHandler = StaticContainer::get('Symfony\Bridge\Monolog\Handler\ConsoleHandler');
         $consoleLogHandler->setOutput(new ConsoleOutput(OutputInterface::VERBOSITY_VERBOSE));
     } else {
-        // HTTP request: logs needs to be dumped on stdout
-        StaticContainer::getContainer()->set('Psr\Log\LoggerInterface', new WebCronArchiveLogger);
+        // HTTP request: logs needs to be dumped in the HTTP response (on top of existing log destinations)
+        /** @var \Monolog\Logger $logger */
+        $logger = StaticContainer::get('Psr\Log\LoggerInterface');
+        $handler = new StreamHandler('php://output', Logger::INFO);
+        $handler->setFormatter(StaticContainer::get('Piwik\Log\Formatter\LineMessageFormatter'));
+        $logger->pushHandler($handler);
     }
 
     $archiver = new Piwik\CronArchive();