Ensure PWD is propagated to workers in mode SWOOLE_PROCESS

During testing, I discovered that when running in mode SWOOLE_PROCESS,
the issue in #15 resurfaced. The solution was to add a `workerstart`
event that resets the PWD based on what is present in the
`RequestHandlerSwooleRunner`. The listener also logs the worker process
ID.

Fixes #15

src/RequestHandlerSwooleRunner.php

@@ -105,10 +105,6 @@ class RequestHandlerSwooleRunner extends RequestHandlerRunner
      */
     private $staticResourceHandler;
 
-    /**
-     * @throws Exception\InvalidConfigException if the configured or default
-     *     document root does not exist.
-     */
     public function __construct(
         RequestHandlerInterface $handler,
         callable $serverRequestFactory,
@@ -139,6 +135,10 @@ function (Throwable $exception) use ($serverRequestErrorResponseGenerator) : Res
 
     /**
      * Run the application
+     *
+     * Determines which action was requested from the command line, and then
+     * executes the task associated with it. If no action was provided, it
+     * assumes "start".
      */
     public function run() : void
     {
@@ -165,20 +165,21 @@ public function run() : void
     }
 
     /**
-     * Start swoole server
+     * Start the swoole HTTP server
      *
      * @param array $options Swoole server options
      */
     public function startServer(array $options = []) : void
     {
         $swooleServer = $this->serverFactory->createSwooleServer($options);
         $swooleServer->on('start', [$this, 'onStart']);
+        $swooleServer->on('workerstart', [$this, 'onWorkerStart']);
         $swooleServer->on('request', [$this, 'onRequest']);
         $swooleServer->start();
     }
 
     /**
-     * Stop swoole server
+     * Stop the swoole HTTP server
      */
     public function stopServer() : void
     {
@@ -231,7 +232,7 @@ public function reloadWorker() : void
     }
 
     /**
-     * Is swoole server running ?
+     * Is the swoole HTTP server running?
      */
     public function isRunning() : bool
     {
@@ -245,21 +246,43 @@ public function isRunning() : bool
     }
 
     /**
-     * On start event for swoole http server
+     * Handle a start event for swoole HTTP server manager process.
+     *
+     * Writes the master and manager PID values to the PidManager, and ensures
+     * the manager and/or workers use the same PWD as the master process.
      */
     public function onStart(SwooleHttpServer $server) : void
     {
         $this->pidManager->write($server->master_pid, $server->manager_pid);
-        $this->logger->info('Swoole is running at {host}:{port}', [
+
+        // Reset CWD
+        chdir($this->cwd);
+
+        $this->logger->info('Swoole is running at {host}:{port}, in {cwd}', [
             'host' => $server->host,
             'port' => $server->port,
+            'cwd'  => getcwd(),
         ]);
+    }
+
+    /**
+     * Handle a workerstart event for swoole HTTP server worker process
+     *
+     * Ensures workers all use the same PWD as the master process.
+     */
+    public function onWorkerStart(SwooleHttpServer $server, int $workerId) : void
+    {
         // Reset CWD
         chdir($this->cwd);
+
+        $this->logger->info('Worker started in {cwd} with ID {pid}', [
+            'cwd' => getcwd(),
+            'pid' => $workerId,
+        ]);
     }
 
     /**
-     * On HTTP request event for swoole http server
+     * Handle an incoming HTTP request
      */
     public function onRequest(
         SwooleHttpRequest $request,

test/RequestHandlerSwooleRunnerTest.php

@@ -107,7 +107,11 @@ public function testRun()
         $swooleServer->expects($this->once())
             ->method('start');
 
-        $swooleServer->expects($this->exactly(2))
+        // Listeners are attached to each of:
+        // - start
+        // - workerstart
+        // - request
+        $swooleServer->expects($this->exactly(3))
             ->method('on');
 
         // Clear command options, like phpunit --colors=always
@@ -129,7 +133,10 @@ public function testOnStart()
         );
 
         $runner->onStart($swooleServer = $this->createMock(SwooleHttpServer::class));
-        $this->expectOutputString("Swoole is running at :0\n");
+        $this->expectOutputString(sprintf(
+            "Swoole is running at :0, in %s\n",
+            getcwd()
+        ));
     }
 
     public function testOnRequestDelegatesToApplicationWhenNoStaticResourceHandlerPresent()