Allow setting a formatter on the PsrHandler, fixes #1070

src/Monolog/Handler/PsrHandler.php

@@ -13,13 +13,18 @@ namespace Monolog\Handler;
 
 use Monolog\Logger;
 use Psr\Log\LoggerInterface;
+use Monolog\Formatter\FormatterInterface;
 
 /**
  * Proxies log messages to an existing PSR-3 compliant logger.
  *
+ * If a formatter is configured, the formatter's output MUST be a string and the
+ * formatted message will be fed to the wrapped PSR logger instead of the original
+ * log record's message.
+ *
  * @author Michael Moussa <michael.moussa@gmail.com>
  */
-class PsrHandler extends AbstractHandler
+class PsrHandler extends AbstractHandler implements FormattableHandlerInterface
 {
     /**
      * PSR-3 compliant logger
@@ -28,6 +33,11 @@ class PsrHandler extends AbstractHandler
      */
     protected $logger;
 
+    /**
+     * @var FormatterInterface
+     */
+    protected $formatter;
+
     /**
      * @param LoggerInterface $logger The underlying PSR-3 compliant logger to which messages will be proxied
      * @param string|int      $level  The minimum logging level at which this handler will be triggered
@@ -49,8 +59,39 @@ class PsrHandler extends AbstractHandler
             return false;
         }
 
-        $this->logger->log(strtolower($record['level_name']), $record['message'], $record['context']);
+        if ($this->formatter) {
+            $formatted = $this->formatter->format($record);
+            $this->logger->log(strtolower($record['level_name']), (string) $formatted, $record['context']);
+        } else {
+            $this->logger->log(strtolower($record['level_name']), $record['message'], $record['context']);
+        }
 
         return false === $this->bubble;
     }
+
+    /**
+     * Sets the formatter.
+     *
+     * @param FormatterInterface $formatter
+     */
+    public function setFormatter(FormatterInterface $formatter): HandlerInterface
+    {
+        $this->formatter = $formatter;
+
+        return $this;
+    }
+
+    /**
+     * Gets the formatter.
+     *
+     * @return FormatterInterface
+     */
+    public function getFormatter(): FormatterInterface
+    {
+        if (!$this->formatter) {
+            throw new \LogicException('No formatter has been set and this handler does not have a default formatter');
+        }
+
+        return $this->formatter;
+    }
 }

tests/Monolog/Handler/PsrHandlerTest.php

@@ -13,6 +13,7 @@ namespace Monolog\Handler;
 
 use Monolog\Test\TestCase;
 use Monolog\Logger;
+use Monolog\Formatter\LineFormatter;
 
 /**
  * @covers Monolog\Handler\PsrHandler::handle
@@ -47,4 +48,21 @@ class PsrHandlerTest extends TestCase
         $handler = new PsrHandler($psrLogger);
         $handler->handle(['level' => $level, 'level_name' => $levelName, 'message' => $message, 'context' => $context]);
     }
+
+    public function testFormatter()
+    {
+        $message = 'Hello, world!';
+        $context = ['foo' => 'bar'];
+        $level = Logger::ERROR;
+        $levelName = 'error';
+
+        $psrLogger = $this->createMock('Psr\Log\NullLogger');
+        $psrLogger->expects($this->once())
+            ->method('log')
+            ->with(strtolower($levelName), 'dummy', $context);
+
+        $handler = new PsrHandler($psrLogger);
+        $handler->setFormatter(new LineFormatter('dummy'));
+        $handler->handle(['level' => $level, 'level_name' => $levelName, 'message' => $message, 'context' => $context, 'extra' => [], 'date' => new \DateTimeImmutable()]);
+    }
 }