Allow the PullLocal daemon to hibernate, and wake it when repositories need an update

Summary: Ref T12298. This allows the PullLocal daemon to hibernate like the Trigger daemon, but automatically wakes it back up when it needs to do something.

Test Plan:
  - Ran `bin/phd debug pulllocal --trace`.
  - Saw the daemon hibernate after doing a checkup on repositories.
  - Saw periodic queries to look for new update messages.
  - After clicking "Update Now" in the web UI to schedule an update, saw the daemon wake up immediately.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T12298

Differential Revision: https://secure.phabricator.com/D17540

src/__phutil_library_map__.php

@@ -3692,6 +3692,7 @@ phutil_register_library_map(array(
     'PhabricatorRepositoryPullEventPHIDType' => 'applications/repository/phid/PhabricatorRepositoryPullEventPHIDType.php',
     'PhabricatorRepositoryPullEventQuery' => 'applications/repository/query/PhabricatorRepositoryPullEventQuery.php',
     'PhabricatorRepositoryPullLocalDaemon' => 'applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php',
+    'PhabricatorRepositoryPullLocalDaemonModule' => 'applications/repository/daemon/PhabricatorRepositoryPullLocalDaemonModule.php',
     'PhabricatorRepositoryPushEvent' => 'applications/repository/storage/PhabricatorRepositoryPushEvent.php',
     'PhabricatorRepositoryPushEventPHIDType' => 'applications/repository/phid/PhabricatorRepositoryPushEventPHIDType.php',
     'PhabricatorRepositoryPushEventQuery' => 'applications/repository/query/PhabricatorRepositoryPushEventQuery.php',
@@ -8987,6 +8988,7 @@ phutil_register_library_map(array(
     'PhabricatorRepositoryPullEventPHIDType' => 'PhabricatorPHIDType',
     'PhabricatorRepositoryPullEventQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
     'PhabricatorRepositoryPullLocalDaemon' => 'PhabricatorDaemon',
+    'PhabricatorRepositoryPullLocalDaemonModule' => 'PhutilDaemonOverseerModule',
     'PhabricatorRepositoryPushEvent' => array(
       'PhabricatorRepositoryDAO',
       'PhabricatorPolicyInterface',

src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php

@@ -228,7 +228,10 @@ final class PhabricatorRepositoryPullLocalDaemon
         continue;
       }
 
-      $this->waitForUpdates($min_sleep, $retry_after);
+      $should_hibernate = $this->waitForUpdates($min_sleep, $retry_after);
+      if ($should_hibernate) {
+        break;
+      }
     }
 
   }
@@ -492,6 +495,10 @@ final class PhabricatorRepositoryPullLocalDaemon
     while (($sleep_until - time()) > 0) {
       $sleep_duration = ($sleep_until - time());
 
+      if ($this->shouldHibernate($sleep_duration)) {
+        return true;
+      }
+
       $this->log(
         pht(
           'Sleeping for %s more second(s)...',
@@ -501,7 +508,7 @@ final class PhabricatorRepositoryPullLocalDaemon
 
       if ($this->shouldExit()) {
         $this->log(pht('Awakened from sleep by graceful shutdown!'));
-        return;
+        return false;
       }
 
       if ($this->loadRepositoryUpdateMessages()) {
@@ -509,6 +516,8 @@ final class PhabricatorRepositoryPullLocalDaemon
         break;
       }
     }
+
+    return false;
   }
 
 }

src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemonModule.php

@@ -0,0 +1,38 @@
+<?php
+
+final class PhabricatorRepositoryPullLocalDaemonModule
+  extends PhutilDaemonOverseerModule {
+
+  private $cursor = 0;
+
+  public function shouldWakePool(PhutilDaemonPool $pool) {
+    $class = $pool->getPoolDaemonClass();
+    if ($class != 'PhabricatorRepositoryPullLocalDaemon') {
+      return false;
+    }
+
+    if ($this->shouldThrottle($class, 1)) {
+      return false;
+    }
+
+    $table = new PhabricatorRepositoryStatusMessage();
+    $table_name = $table->getTableName();
+    $conn = $table->establishConnection('r');
+
+    $row = queryfx_one(
+      $conn,
+      'SELECT id FROM %T WHERE statusType = %s
+        AND id > %d ORDER BY id DESC LIMIT 1',
+      $table_name,
+      PhabricatorRepositoryStatusMessage::TYPE_NEEDS_UPDATE,
+      $this->cursor);
+
+    if (!$row) {
+      return false;
+    }
+
+    $this->cursor = (int)$row['id'];
+    return true;
+  }
+
+}

src/infrastructure/daemon/overseer/PhabricatorDaemonOverseerModule.php

@@ -10,18 +10,9 @@ final class PhabricatorDaemonOverseerModule
   extends PhutilDaemonOverseerModule {
 
   private $configVersion;
-  private $timestamp;
-
-  public function __construct() {
-    $this->timestamp = PhabricatorTime::getNow();
-  }
 
   public function shouldReloadDaemons() {
-    $now = PhabricatorTime::getNow();
-    $ago = ($now - $this->timestamp);
-
-    // Don't check more than once every 10 seconds.
-    if ($ago < 10) {
+    if ($this->shouldThrottle('reload', 10)) {
       return false;
     }
 
@@ -47,25 +38,17 @@ final class PhabricatorDaemonOverseerModule
   }
 
   /**
-   * Update the configuration version and timestamp.
+   * Check and update the configuration version.
    *
    * @return bool  True if the daemons should restart, otherwise false.
    */
   private function updateConfigVersion() {
-    $config_version = $this->loadConfigVersion();
-    $this->timestamp = PhabricatorTime::getNow();
+    $old_version = $this->configVersion;
+    $new_version = $this->loadConfigVersion();
 
-    if (!$this->configVersion) {
-      $this->configVersion = $config_version;
-      return false;
-    }
+    $this->configVersion = $new_version;
 
-    if ($this->configVersion != $config_version) {
-      $this->configVersion = $config_version;
-      return true;
-    }
-
-    return false;
+    return ($old_version != $new_version);
   }
 
 }