Add some default context to logs if we know it.

If we know the user ID and email, add it to the log context for easier
searching for a given users error.

src/Illuminate/Foundation/Exceptions/Handler.php

@@ -6,6 +6,7 @@
 use Psr\Log\LoggerInterface;
 use Illuminate\Http\Response;
 use Illuminate\Routing\Router;
+use Illuminate\Support\Facades\Auth;
 use Illuminate\Http\RedirectResponse;
 use Illuminate\Auth\AuthenticationException;
 use Illuminate\Contracts\Container\Container;
@@ -69,7 +70,7 @@ public function report(Exception $e)
             throw $e; // throw the original exception
         }
 
-        $logger->error($e);
+        $logger->error($e, $this->context());
     }
 
     /**
@@ -98,6 +99,20 @@ protected function shouldntReport(Exception $e)
         }));
     }
 
+    /**
+     * Get the default context variables for logging.
+     *
+     * @return array
+     */
+    protected function context()
+    {
+        return array_filter([
+            'userId' => Auth::id(),
+            'email' => Auth::check() && isset(Auth::user()->email)
+                        ? Auth::user()->email : null,
+        ]);
+    }
+
     /**
      * Render an exception into a response.
      *