Properly log error events emitted by the slave HttpServer

Author: acasademont

src/ProcessManager.php

@@ -1295,10 +1295,10 @@ protected function newSlaveInstance($port)
             'data',
             function ($data) use ($port) {
                 if ($this->lastWorkerErrorPrintBy !== $port) {
-                    $this->output->writeln("<info>--- Worker $port stderr ---</info>");
+                    $this->output->writeln(sprintf('<info>--- Worker %u stderr ---</info>', $port));
                     $this->lastWorkerErrorPrintBy = $port;
                 }
-                $this->output->write("<error>$data</error>");
+                $this->output->writeln(sprintf('<error>%s</error>', trim($data)));
             }
         );
     }

src/ProcessSlave.php

@@ -336,6 +336,11 @@ function ($controller) {
                 }
 
                 $httpServer->listen($this->server);
+                if ($this->isLogging()) {
+                    $httpServer->on('error', function (\Exception $e) {
+                        error_log(sprintf('Worker error while processing the request. %s: %s', get_class($e), $e->getMessage()));
+                    });
+                }
 
                 $this->sendMessage($this->controller, 'register', ['pid' => getmypid(), 'port' => $port]);
             }