Use a custom quit message when gracefully shutting down the IRC bot

Summary: Fixes T3173. This doesn't actually fix T3173 but I'm going to redirect that. It does make the bot quit IRC gracefully, with a nicer quit message, which can be customized.

Test Plan: Got a bot to quit IRC with nice messages.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T3173

Differential Revision: https://secure.phabricator.com/D10257

src/infrastructure/daemon/bot/PhabricatorBot.php

@@ -83,6 +83,8 @@ final class PhabricatorBot extends PhabricatorDaemon {
       ->connect();
 
     $this->runLoop();
+
+    $this->protocolAdapter->disconnect();
   }
 
   public function getConfig($key, $default = null) {
@@ -104,6 +106,7 @@ final class PhabricatorBot extends PhabricatorDaemon {
         $handler->runBackgroundTasks();
       }
     } while (!$this->shouldExit());
+
   }
 
   public function writeMessage(PhabricatorBotMessage $message) {

src/infrastructure/daemon/bot/adapter/PhabricatorBaseProtocolAdapter.php

@@ -21,6 +21,13 @@ abstract class PhabricatorBaseProtocolAdapter {
    */
   abstract public function connect();
 
+  /**
+   * Disconnect from the service.
+   */
+  public function disconnect() {
+    return;
+  }
+
   /**
    * This is the spout for messages coming in from the protocol.
    * This will be called in the main event loop of the bot daemon

src/infrastructure/daemon/bot/adapter/PhabricatorIRCProtocolAdapter.php

@@ -71,8 +71,13 @@ final class PhabricatorIRCProtocolAdapter
 
     $ok = @stream_select($read, $write, $except, $timeout_sec = 1);
     if ($ok === false) {
-      throw new Exception(
-        'socket_select() failed: '.socket_strerror(socket_last_error()));
+      // We may have been interrupted by a signal, like a SIGINT. Try
+      // selecting again. If the second select works, conclude that the failure
+      // was most likely because we were signaled.
+      $ok = @stream_select($read, $write, $except, $timeout_sec = 0);
+      if ($ok === false) {
+        throw new Exception('stream_select() failed!');
+      }
     }
 
     if ($read) {
@@ -102,6 +107,8 @@ final class PhabricatorIRCProtocolAdapter
         $len = fwrite($this->socket, $this->writeBuffer);
         if ($len === false) {
           throw new Exception('fwrite() failed!');
+        } else if ($len === 0) {
+          break;
         } else {
           $messages[] = id(new PhabricatorBotMessage())
             ->setCommand('LOG')
@@ -250,8 +257,22 @@ final class PhabricatorIRCProtocolAdapter
       $data);
   }
 
-  public function __destruct() {
-    $this->write('QUIT Goodbye.');
-    fclose($this->socket);
+  public function disconnect() {
+    // NOTE: FreeNode doesn't show quit messages if you've recently joined a
+    // channel, presumably to prevent some kind of abuse. If you're testing
+    // this, you may need to stay connected to the network for a few minutes
+    // before it works. If you disconnect too quickly, the server will replace
+    // your message with a "Client Quit" message.
+
+    $quit = $this->getConfig('quit', pht('Shutting down.'));
+    $this->write("QUIT :{$quit}");
+
+    // Flush the write buffer.
+    while (strlen($this->writeBuffer)) {
+      $this->getNextMessages(0);
+    }
+
+    @fclose($this->socket);
+    $this->socket = null;
   }
 }