Make ./bin/aphlict behave more like a service.

Summary: Fixes T5126. Provide `start`, `stop`, `restart`, `debug` and `status` workflows for `./bin/aphlict`. This makes it easier to manage Aphlict as if it were a service.

Test Plan:
```
> sudo ./bin/aphlict status
Aphlict is not running.

> sudo ./bin/aphlict stop
Aphlict is not running.

> sudo ./bin/aphlict start
Aphlict Server started.

> sudo ./bin/aphlict status
Aphlict (12880) is running.

> sudo ./bin/aphlict restart
Stopping Aphlict Server (12880)...
Aphlict Server (12880) exited normally.
Aphlict Server started.

> sudo ./bin/aphlict stop
Stopping Aphlict Server (12895)...
Aphlict Server (12895) exited normally.

> sudo ./bin/aphlict debug
Starting Aphlict server in foreground...
Launching server:

    $ node '/usr/src/phabricator/src/applications/aphlict/management/../../../../support/aphlict/server/aphlict_server.js' --port='22280' --admin='22281' --host='localhost' --user='aphlict'

[Fri May 30 2014 09:56:14 GMT+0000 (UTC)] Started Server (PID 12911)
```

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: hach-que, epriestley, Korvin

Maniphest Tasks: T5126

Differential Revision: https://secure.phabricator.com/D9226

src/__phutil_library_map__.php

@@ -1105,6 +1105,12 @@ phutil_register_library_map(array(
     'PhabricatorActionView' => 'view/layout/PhabricatorActionView.php',
     'PhabricatorAllCapsTranslation' => 'infrastructure/internationalization/translation/PhabricatorAllCapsTranslation.php',
     'PhabricatorAnchorView' => 'view/layout/PhabricatorAnchorView.php',
+    'PhabricatorAphlictManagementDebugWorkflow' => 'applications/aphlict/management/PhabricatorAphlictManagementDebugWorkflow.php',
+    'PhabricatorAphlictManagementRestartWorkflow' => 'applications/aphlict/management/PhabricatorAphlictManagementRestartWorkflow.php',
+    'PhabricatorAphlictManagementStartWorkflow' => 'applications/aphlict/management/PhabricatorAphlictManagementStartWorkflow.php',
+    'PhabricatorAphlictManagementStatusWorkflow' => 'applications/aphlict/management/PhabricatorAphlictManagementStatusWorkflow.php',
+    'PhabricatorAphlictManagementStopWorkflow' => 'applications/aphlict/management/PhabricatorAphlictManagementStopWorkflow.php',
+    'PhabricatorAphlictManagementWorkflow' => 'applications/aphlict/management/PhabricatorAphlictManagementWorkflow.php',
     'PhabricatorAphrontBarExample' => 'applications/uiexample/examples/PhabricatorAphrontBarExample.php',
     'PhabricatorAphrontViewTestCase' => 'view/__tests__/PhabricatorAphrontViewTestCase.php',
     'PhabricatorAppSearchEngine' => 'applications/meta/query/PhabricatorAppSearchEngine.php',
@@ -3871,6 +3877,12 @@ phutil_register_library_map(array(
     'PhabricatorActionView' => 'AphrontView',
     'PhabricatorAllCapsTranslation' => 'PhabricatorTranslation',
     'PhabricatorAnchorView' => 'AphrontView',
+    'PhabricatorAphlictManagementDebugWorkflow' => 'PhabricatorAphlictManagementWorkflow',
+    'PhabricatorAphlictManagementRestartWorkflow' => 'PhabricatorAphlictManagementWorkflow',
+    'PhabricatorAphlictManagementStartWorkflow' => 'PhabricatorAphlictManagementWorkflow',
+    'PhabricatorAphlictManagementStatusWorkflow' => 'PhabricatorAphlictManagementWorkflow',
+    'PhabricatorAphlictManagementStopWorkflow' => 'PhabricatorAphlictManagementWorkflow',
+    'PhabricatorAphlictManagementWorkflow' => 'PhabricatorManagementWorkflow',
     'PhabricatorAphrontBarExample' => 'PhabricatorUIExample',
     'PhabricatorAphrontViewTestCase' => 'PhabricatorTestCase',
     'PhabricatorAppSearchEngine' => 'PhabricatorApplicationSearchEngine',

src/applications/aphlict/management/PhabricatorAphlictManagementDebugWorkflow.php

@@ -0,0 +1,21 @@
+<?php
+
+final class PhabricatorAphlictManagementDebugWorkflow
+  extends PhabricatorAphlictManagementWorkflow {
+
+  public function didConstruct() {
+    $this
+      ->setName('debug')
+      ->setSynopsis(
+        pht(
+          'Start the notifications server in the foreground and print large '.
+          'volumes of diagnostic information to the console.'))
+      ->setArguments(array());
+  }
+
+  public function execute(PhutilArgumentParser $args) {
+    $this->willLaunch();
+    return $this->launch(true);
+  }
+
+}

src/applications/aphlict/management/PhabricatorAphlictManagementRestartWorkflow.php

@@ -0,0 +1,21 @@
+<?php
+
+final class PhabricatorAphlictManagementRestartWorkflow
+  extends PhabricatorAphlictManagementWorkflow {
+
+  public function didConstruct() {
+    $this
+      ->setName('restart')
+      ->setSynopsis(pht('Stop, then start the notifications server.'))
+      ->setArguments(array());
+  }
+
+  public function execute(PhutilArgumentParser $args) {
+    $err = $this->executeStopCommand();
+    if ($err) {
+      return $err;
+    }
+    return $this->executeStartCommand();
+  }
+
+}

src/applications/aphlict/management/PhabricatorAphlictManagementStartWorkflow.php

@@ -0,0 +1,17 @@
+<?php
+
+final class PhabricatorAphlictManagementStartWorkflow
+  extends PhabricatorAphlictManagementWorkflow {
+
+  public function didConstruct() {
+    $this
+      ->setName('start')
+      ->setSynopsis(pht('Start the notifications server.'))
+      ->setArguments(array());
+  }
+
+  public function execute(PhutilArgumentParser $args) {
+    return $this->executeStartCommand();
+  }
+
+}

src/applications/aphlict/management/PhabricatorAphlictManagementStatusWorkflow.php

@@ -0,0 +1,26 @@
+<?php
+
+final class PhabricatorAphlictManagementStatusWorkflow
+  extends PhabricatorAphlictManagementWorkflow {
+
+  public function didConstruct() {
+    $this
+      ->setName('status')
+      ->setSynopsis(pht('Show the status of the notifications server.'))
+      ->setArguments(array());
+  }
+
+  public function execute(PhutilArgumentParser $args) {
+    $console = PhutilConsole::getConsole();
+    $pid = $this->getPID();
+
+    if (!$pid) {
+      $console->writeErr(pht("Aphlict is not running.\n"));
+      return 1;
+    }
+
+    $console->writeOut(pht("Aphlict (%s) is running.\n", $pid));
+    return 0;
+  }
+
+}

src/applications/aphlict/management/PhabricatorAphlictManagementStopWorkflow.php

@@ -0,0 +1,17 @@
+<?php
+
+final class PhabricatorAphlictManagementStopWorkflow
+  extends PhabricatorAphlictManagementWorkflow {
+
+  public function didConstruct() {
+    $this
+      ->setName('stop')
+      ->setSynopsis(pht('Stop the notifications server.'))
+      ->setArguments(array());
+  }
+
+  public function execute(PhutilArgumentParser $args) {
+    return $this->executeStopCommand();
+  }
+
+}

src/applications/aphlict/management/PhabricatorAphlictManagementWorkflow.php

@@ -0,0 +1,204 @@
+<?php
+
+abstract class PhabricatorAphlictManagementWorkflow
+  extends PhabricatorManagementWorkflow {
+
+  final public function getPIDPath() {
+    return PhabricatorEnv::getEnvConfig('notification.pidfile');
+  }
+
+  final public function getPID() {
+    $pid = null;
+    if (Filesystem::pathExists($this->getPIDPath())) {
+      $pid = (int)Filesystem::readFile($this->getPIDPath());
+    }
+    return $pid;
+  }
+
+  final public function cleanup($signo = '?') {
+    global $g_future;
+    if ($g_future) {
+      $g_future->resolveKill();
+      $g_future = null;
+    }
+
+    Filesystem::remove($this->getPIDPath());
+
+    exit(1);
+  }
+
+  public static function requireExtensions() {
+    self::mustHaveExtension('pcntl');
+    self::mustHaveExtension('posix');
+  }
+
+  private static function mustHaveExtension($ext) {
+    if (!extension_loaded($ext)) {
+      echo "ERROR: The PHP extension '{$ext}' is not installed. You must ".
+           "install it to run aphlict on this machine.\n";
+      exit(1);
+    }
+
+    $extension = new ReflectionExtension($ext);
+    foreach ($extension->getFunctions() as $function) {
+      $function = $function->name;
+      if (!function_exists($function)) {
+        echo "ERROR: The PHP function {$function}() is disabled. You must ".
+             "enable it to run aphlict on this machine.\n";
+        exit(1);
+      }
+    }
+  }
+
+  final protected function willLaunch() {
+    $console = PhutilConsole::getConsole();
+
+    $pid = $this->getPID();
+    if ($pid) {
+      $console->writeErr(
+        "Unable to start notifications server because it is already ".
+        "running.\n");
+      exit(1);
+    }
+
+    if (posix_getuid() != 0) {
+      $console->writeErr(
+        "You must run this script as root; the Aphlict server needs to bind ".
+        "to privileged ports.\n");
+      exit(1);
+    }
+
+    if (!Filesystem::binaryExists('node')) {
+      $console->writeErr(
+        "`node` is not in \$PATH. You must install Node.js to run the Aphlict ".
+        "server.\n");
+      exit(1);
+    }
+  }
+
+  final protected function launch($debug = false) {
+    $console = PhutilConsole::getConsole();
+
+    if ($debug) {
+      $console->writeOut(pht("Starting Aphlict server in foreground...\n"));
+    } else {
+      Filesystem::writeFile($this->getPIDPath(), getmypid());
+    }
+
+    $server_uri = PhabricatorEnv::getEnvConfig('notification.server-uri');
+    $server_uri = new PhutilURI($server_uri);
+
+    $client_uri = PhabricatorEnv::getEnvConfig('notification.client-uri');
+    $client_uri = new PhutilURI($client_uri);
+
+    $user = PhabricatorEnv::getEnvConfig('notification.user');
+    $log  = PhabricatorEnv::getEnvConfig('notification.log');
+
+    $server_argv = array();
+    $server_argv[] = csprintf('--port=%s', $client_uri->getPort());
+    $server_argv[] = csprintf('--admin=%s', $server_uri->getPort());
+    $server_argv[] = csprintf('--host=%s', $server_uri->getDomain());
+
+    if ($user) {
+      $server_argv[] = csprintf('--user=%s', $user);
+    }
+
+    if (!$debug) {
+      $server_argv[] = csprintf('--log=%s', $log);
+    }
+
+    $command = csprintf(
+      'node %s %C',
+      dirname(__FILE__).'/../../../../support/aphlict/server/aphlict_server.js',
+      implode(' ', $server_argv));
+
+    if (!$debug) {
+      declare(ticks = 1);
+      pcntl_signal(SIGINT, array($this, 'cleanup'));
+      pcntl_signal(SIGTERM, array($this, 'cleanup'));
+    }
+    register_shutdown_function(array($this, 'cleanup'));
+
+    if ($debug) {
+      $console->writeOut("Launching server:\n\n    $ ".$command."\n\n");
+
+      $err = phutil_passthru('%C', $command);
+      $console->writeOut(">>> Server exited!\n");
+      exit($err);
+    } else {
+      while (true) {
+        global $g_future;
+        $g_future = new ExecFuture('exec %C', $command);
+        $g_future->resolve();
+
+        // If the server exited, wait a couple of seconds and restart it.
+        unset($g_future);
+        sleep(2);
+      }
+    }
+  }
+
+
+/* -(  Commands  )----------------------------------------------------------- */
+
+
+  final protected function executeStartCommand() {
+    $console = PhutilConsole::getConsole();
+    $this->willLaunch();
+
+    $pid = pcntl_fork();
+    if ($pid < 0) {
+      throw new Exception('Failed to fork()!');
+    } else if ($pid) {
+      $console->writeErr(pht("Aphlict Server started.\n"));
+      exit(0);
+    }
+
+    // When we fork, the child process will inherit its parent's set of open
+    // file descriptors. If the parent process of bin/aphlict is waiting for
+    // bin/aphlict's file descriptors to close, it will be stuck waiting on
+    // the daemonized process. (This happens if e.g. bin/aphlict is started
+    // in another script using passthru().)
+    fclose(STDOUT);
+    fclose(STDERR);
+
+    $this->launch();
+    return 0;
+  }
+
+
+  final protected function executeStopCommand() {
+    $console = PhutilConsole::getConsole();
+
+    $pid = $this->getPID();
+    if (!$pid) {
+      $console->writeErr(pht("Aphlict is not running.\n"));
+      return 0;
+    }
+
+    $console->writeErr(pht("Stopping Aphlict Server (%s)...\n", $pid));
+    posix_kill($pid, SIGINT);
+
+    $start = time();
+    do {
+      if (!PhabricatorDaemonReference::isProcessRunning($pid)) {
+        $console->writeOut(
+          "%s\n",
+          pht('Aphlict Server (%s) exited normally.', $pid));
+        $pid = null;
+        break;
+      }
+      usleep(100000);
+    } while (time() < $start + 5);
+
+    if ($pid) {
+      $console->writeErr(pht('Sending %s a SIGKILL.', $pid)."\n");
+      posix_kill($pid, SIGKILL);
+      unset($pid);
+    }
+
+    Filesystem::remove($this->getPIDPath());
+    return 0;
+  }
+
+}

support/aphlict/server/aphlict_launcher.php

@@ -1,164 +1,26 @@
 #!/usr/bin/env php
 <?php
 
-// This is a launcher for the 'aphlict' Node.js notification server that
-// provides real-time notifications for Phabricator. It handles reading
-// configuration from the Phabricator config, daemonizing the server,
-// restarting the server if it crashes, and some basic sanity checks.
-
-
 $root = dirname(dirname(dirname(dirname(__FILE__))));
 require_once $root.'/scripts/__init_script__.php';
 
-
-// >>> Options and Arguments ---------------------------------------------------
+PhabricatorAphlictManagementWorkflow::requireExtensions();
 
 $args = new PhutilArgumentParser($argv);
 $args->setTagline('manage Aphlict notification server');
-$args->setSynopsis(<<<EOHELP
-**aphlict** [__options__]
-  Start (or restart) the Aphlict server.
-EOHELP
+$args->setSynopsis(<<<EOSYNOPSIS
+**aphlict** __command__ [__options__]
+    Manage the Aphlict server.
+
+EOSYNOPSIS
   );
 $args->parseStandardArguments();
-$args->parse(array(
-  array(
-    'name' => 'foreground',
-    'help' => 'Run in the foreground instead of daemonizing.',
-  ),
+
+$args->parseWorkflows(array(
+  new PhabricatorAphlictManagementStatusWorkflow(),
+  new PhabricatorAphlictManagementStartWorkflow(),
+  new PhabricatorAphlictManagementStopWorkflow(),
+  new PhabricatorAphlictManagementRestartWorkflow(),
+  new PhabricatorAphlictManagementDebugWorkflow(),
+  new PhutilHelpArgumentWorkflow(),
 ));
-
-if (posix_getuid() != 0) {
-  throw new Exception(
-    "You must run this script as root; the Aphlict server needs to bind to ".
-    "privileged ports.");
-}
-
-list($err) = exec_manual('node -v');
-if ($err) {
-  throw new Exception(
-    '`node` is not in $PATH. You must install Node.js to run the Aphlict '.
-    'server.');
-}
-
-$server_uri = PhabricatorEnv::getEnvConfig('notification.server-uri');
-$server_uri = new PhutilURI($server_uri);
-
-$client_uri = PhabricatorEnv::getEnvConfig('notification.client-uri');
-$client_uri = new PhutilURI($client_uri);
-
-$user = PhabricatorEnv::getEnvConfig('notification.user');
-$log  = PhabricatorEnv::getEnvConfig('notification.log');
-
-$g_pidfile = PhabricatorEnv::getEnvConfig('notification.pidfile');
-$g_future  = null;
-
-$foreground = $args->getArg('foreground');
-
-// Build the argument list for the server itself.
-$server_argv = array();
-$server_argv[] = csprintf('--port=%s', $client_uri->getPort());
-$server_argv[] = csprintf('--admin=%s', $server_uri->getPort());
-$server_argv[] = csprintf('--host=%s', $server_uri->getDomain());
-
-if ($user) {
-  $server_argv[] = csprintf('--user=%s', $user);
-}
-
-if ($log) {
-  $server_argv[] = csprintf('--log=%s', $log);
-}
-
-
-// >>> Foreground / Background -------------------------------------------------
-
-// If we start in the foreground, we use phutil_passthru() below to show any
-// output from the server to the console, but this means *this* process won't
-// receive signals until the child exits. If we write our pid to the pidfile
-// and then another process starts, it will try to SIGTERM us but we won't
-// receive the signal. Since the effect is the same and this is simpler, just
-// ignore the pidfile if launched in `--foreground` mode; this is a debugging
-// mode anyway.
-if ($foreground) {
-  echo "Starting server in foreground, ignoring pidfile...\n";
-  $g_pidfile = null;
-} else {
-  $pid = pcntl_fork();
-  if ($pid < 0) {
-    throw new Exception("Failed to fork()!");
-  } else if ($pid) {
-    exit(0);
-  }
-  // When we fork, the child process will inherit its parent's set of open
-  // file descriptors. If the parent process of bin/aphlict is waiting for
-  // bin/aphlict's file descriptors to close, it will be stuck waiting on
-  // the daemonized process. (This happens if e.g. bin/aphlict is started
-  // in another script using passthru().)
-  fclose(STDOUT);
-  fclose(STDERR);
-}
-
-
-// >>> Signals / Cleanup -------------------------------------------------------
-
-function cleanup($sig = '?') {
-  global $g_pidfile;
-  if ($g_pidfile) {
-    Filesystem::remove($g_pidfile);
-    $g_pidfile = null;
-  }
-
-  global $g_future;
-  if ($g_future) {
-    $g_future->resolveKill();
-    $g_future = null;
-  }
-
-  exit(1);
-}
-
-if (!$foreground) {
-  declare(ticks = 1);
-  pcntl_signal(SIGTERM, 'cleanup');
-}
-
-register_shutdown_function('cleanup');
-
-
-// >>> pidfile -----------------------------------------------------------------
-
-if ($g_pidfile) {
-  if (Filesystem::pathExists($g_pidfile)) {
-    $old_pid = (int)Filesystem::readFile($g_pidfile);
-    posix_kill($old_pid, SIGTERM);
-    sleep(1);
-    Filesystem::remove($g_pidfile);
-  }
-  Filesystem::writeFile($g_pidfile, getmypid());
-}
-
-
-// >>> run ---------------------------------------------------------------------
-
-$command = csprintf(
-  'node %s %C',
-  dirname(__FILE__).'/aphlict_server.js',
-  implode(' ', $server_argv));
-
-if ($foreground) {
-  echo "Launching server:\n\n";
-  echo "    $ ".$command."\n\n";
-
-  $err = phutil_passthru('%C', $command);
-  echo ">>> Server exited!\n";
-  exit($err);
-} else {
-  while (true) {
-    $g_future = new ExecFuture('exec %C', $command);
-    $g_future->resolve();
-
-    // If the server exited, wait a couple of seconds and restart it.
-    unset($g_future);
-    sleep(2);
-  }
-}