Rough cut of Workers

Summary: workers do work, provided I have written them correctly. perhaps it
is so.

Test Plan:

Reviewers:

CC:

resources/sql/patches/005.workers.sql

@@ -0,0 +1,20 @@
+create database phabricator_worker;
+
+create table phabricator_worker.worker_task (
+  id int unsigned not null auto_increment primary key,
+  taskClass varchar(255) not null,
+  leaseOwner varchar(255),
+  leaseExpires int unsigned,
+  priority bigint unsigned not null,
+  failureCount int unsigned not null,
+  key(taskClass),
+  key(leaseOwner),
+  key(leaseExpires)
+);
+
+create table phabricator_worker.worker_taskdata (
+  id int unsigned not null auto_increment primary key,
+  taskID int unsigned not null,
+  data longblob not null,
+  unique key (taskID)
+);

src/__phutil_library_map__.php

@@ -190,6 +190,8 @@ phutil_register_library_map(array(
     'PhabricatorConduitMethodCallLog' => 'applications/conduit/storage/methodcalllog',
     'PhabricatorController' => 'applications/base/controller/base',
     'PhabricatorDaemon' => 'infrastructure/daemon/base',
+    'PhabricatorDaemonConsoleController' => 'applications/daemon/controller/console',
+    'PhabricatorDaemonController' => 'applications/daemon/controller/base',
     'PhabricatorDirectoryCategory' => 'applications/directory/storage/category',
     'PhabricatorDirectoryCategoryDeleteController' => 'applications/directory/controller/categorydelete',
     'PhabricatorDirectoryCategoryEditController' => 'applications/directory/controller/categoryedit',
@@ -214,6 +216,7 @@ phutil_register_library_map(array(
     'PhabricatorFileURI' => 'applications/files/uri',
     'PhabricatorFileUploadController' => 'applications/files/controller/upload',
     'PhabricatorFileViewController' => 'applications/files/controller/view',
+    'PhabricatorGoodForNothingWorker' => 'infrastructure/daemon/workers/worker/goodfornothing',
     'PhabricatorHandleObjectSelectorDataView' => 'applications/phid/handle/view/selector',
     'PhabricatorLiskDAO' => 'applications/base/storage/lisk',
     'PhabricatorLoginController' => 'applications/auth/controller/login',
@@ -300,11 +303,12 @@ phutil_register_library_map(array(
     'PhabricatorSearchQuery' => 'applications/search/storage/query',
     'PhabricatorSearchRelationship' => 'applications/search/constants/relationship',
     'PhabricatorStandardPageView' => 'view/page/standard',
-    'PhabricatorTimelineCursor' => 'applications/timeline/storage/cursor',
-    'PhabricatorTimelineDAO' => 'applications/timeline/storage/base',
-    'PhabricatorTimelineEvent' => 'applications/timeline/storage/event',
-    'PhabricatorTimelineEventData' => 'applications/timeline/storage/eventdata',
-    'PhabricatorTimelineIterator' => 'applications/timeline/cursor/iterator',
+    'PhabricatorTaskmasterDaemon' => 'infrastructure/daemon/workers/taskmaster',
+    'PhabricatorTimelineCursor' => 'infrastructure/daemon/timeline/storage/cursor',
+    'PhabricatorTimelineDAO' => 'infrastructure/daemon/timeline/storage/base',
+    'PhabricatorTimelineEvent' => 'infrastructure/daemon/timeline/storage/event',
+    'PhabricatorTimelineEventData' => 'infrastructure/daemon/timeline/storage/eventdata',
+    'PhabricatorTimelineIterator' => 'infrastructure/daemon/timeline/cursor/iterator',
     'PhabricatorTypeaheadCommonDatasourceController' => 'applications/typeahead/controller/common',
     'PhabricatorTypeaheadDatasourceController' => 'applications/typeahead/controller/base',
     'PhabricatorUser' => 'applications/people/storage/user',
@@ -312,6 +316,10 @@ phutil_register_library_map(array(
     'PhabricatorUserOAuthInfo' => 'applications/people/storage/useroauthinfo',
     'PhabricatorUserProfile' => 'applications/people/storage/profile',
     'PhabricatorUserSettingsController' => 'applications/people/controller/settings',
+    'PhabricatorWorker' => 'infrastructure/daemon/workers/worker',
+    'PhabricatorWorkerDAO' => 'infrastructure/daemon/workers/storage/base',
+    'PhabricatorWorkerTask' => 'infrastructure/daemon/workers/storage/task',
+    'PhabricatorWorkerTaskData' => 'infrastructure/daemon/workers/storage/taskdata',
     'PhabricatorXHProfController' => 'applications/xhprof/controller/base',
     'PhabricatorXHProfProfileController' => 'applications/xhprof/controller/profile',
     'PhabricatorXHProfProfileSymbolView' => 'applications/xhprof/view/symbol',
@@ -473,6 +481,8 @@ phutil_register_library_map(array(
     'PhabricatorConduitMethodCallLog' => 'PhabricatorConduitDAO',
     'PhabricatorController' => 'AphrontController',
     'PhabricatorDaemon' => 'PhutilDaemon',
+    'PhabricatorDaemonConsoleController' => 'PhabricatorDaemonController',
+    'PhabricatorDaemonController' => 'PhabricatorController',
     'PhabricatorDirectoryCategory' => 'PhabricatorDirectoryDAO',
     'PhabricatorDirectoryCategoryDeleteController' => 'PhabricatorDirectoryController',
     'PhabricatorDirectoryCategoryEditController' => 'PhabricatorDirectoryController',
@@ -495,6 +505,7 @@ phutil_register_library_map(array(
     'PhabricatorFileStorageBlob' => 'PhabricatorFileDAO',
     'PhabricatorFileUploadController' => 'PhabricatorFileController',
     'PhabricatorFileViewController' => 'PhabricatorFileController',
+    'PhabricatorGoodForNothingWorker' => 'PhabricatorWorker',
     'PhabricatorLiskDAO' => 'LiskDAO',
     'PhabricatorLoginController' => 'PhabricatorAuthController',
     'PhabricatorLogoutController' => 'PhabricatorAuthController',
@@ -567,6 +578,7 @@ phutil_register_library_map(array(
     'PhabricatorSearchMySQLExecutor' => 'PhabricatorSearchExecutor',
     'PhabricatorSearchQuery' => 'PhabricatorSearchDAO',
     'PhabricatorStandardPageView' => 'AphrontPageView',
+    'PhabricatorTaskmasterDaemon' => 'PhabricatorDaemon',
     'PhabricatorTimelineCursor' => 'PhabricatorTimelineDAO',
     'PhabricatorTimelineDAO' => 'PhabricatorLiskDAO',
     'PhabricatorTimelineEvent' => 'PhabricatorTimelineDAO',
@@ -578,6 +590,9 @@ phutil_register_library_map(array(
     'PhabricatorUserOAuthInfo' => 'PhabricatorUserDAO',
     'PhabricatorUserProfile' => 'PhabricatorUserDAO',
     'PhabricatorUserSettingsController' => 'PhabricatorPeopleController',
+    'PhabricatorWorkerDAO' => 'PhabricatorLiskDAO',
+    'PhabricatorWorkerTask' => 'PhabricatorWorkerDAO',
+    'PhabricatorWorkerTaskData' => 'PhabricatorWorkerDAO',
     'PhabricatorXHProfController' => 'PhabricatorController',
     'PhabricatorXHProfProfileController' => 'PhabricatorXHProfController',
     'PhabricatorXHProfProfileSymbolView' => 'AphrontView',

src/aphront/default/configuration/AphrontDefaultApplicationConfiguration.php

@@ -200,6 +200,10 @@ class AphrontDefaultApplicationConfiguration
         ),
       ),
 
+      '/daemon/' => array(
+        '$' => 'PhabricatorDaemonConsoleController',
+      ),
+
     );
   }
 

src/applications/daemon/controller/base/PhabricatorDaemonController.php

@@ -0,0 +1,42 @@
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+abstract class PhabricatorDaemonController extends PhabricatorController {
+
+  public function buildStandardPageResponse($view, array $data) {
+    $page = $this->buildStandardPageView();
+
+    $page->setApplicationName('Daemon Console');
+    $page->setBaseURI('/');
+    $page->setTitle(idx($data, 'title'));
+    $page->setTabs(
+      array(
+        'console' => array(
+          'href' => '/daemon/',
+          'name' => 'Console',
+        ),
+      ),
+      idx($data, 'tab'));
+    $page->setGlyph("\xE2\x98\xAF");
+    $page->appendChild($view);
+
+    $response = new AphrontWebpageResponse();
+    return $response->setContent($page->render());
+  }
+
+}

src/applications/daemon/controller/base/__init__.php

@@ -0,0 +1,15 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'aphront/response/webpage');
+phutil_require_module('phabricator', 'applications/base/controller/base');
+
+phutil_require_module('phutil', 'utils');
+
+
+phutil_require_source('PhabricatorDaemonController.php');

src/applications/daemon/controller/console/PhabricatorDaemonConsoleController.php

@@ -0,0 +1,70 @@
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+class PhabricatorDaemonConsoleController extends PhabricatorDaemonController {
+
+  public function processRequest() {
+    $request = $this->getRequest();
+
+    if ($request->getStr('new')) {
+      $task = new PhabricatorWorkerTask();
+      $task->setTaskClass('PhabricatorGoodForNothingWorker');
+      $task->setPriority(4);
+      $task->setFailureCount(0);
+      $task->save();
+    }
+
+    $tasks = id(new PhabricatorWorkerTask())
+      ->loadAll();
+
+    $rows = array();
+    foreach ($tasks as $task) {
+      $rows[] = array(
+        $task->getID(),
+        $task->getTaskClass(),
+        $task->getLeaseOwner(),
+        $task->getLeaseExpires(),
+        $task->getPriority(),
+        $task->getFailureCount(),
+      );
+    }
+
+    $table = new AphrontTableView($rows);
+    $table->setHeaders(
+      array(
+        'ID',
+        'Class',
+        'Owner',
+        'Expries',
+        'Priority',
+        'Count',
+      ));
+
+    $panel = new AphrontPanelView();
+    $panel->setHeader('Tasks');
+    $panel->appendChild($table);
+
+    return $this->buildStandardPageResponse(
+      $panel,
+      array(
+        'title' => 'Console',
+        'tab'   => 'console',
+      ));
+  }
+
+}

src/applications/daemon/controller/console/__init__.php

@@ -0,0 +1,17 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'applications/daemon/controller/base');
+phutil_require_module('phabricator', 'infrastructure/daemon/workers/storage/task');
+phutil_require_module('phabricator', 'view/control/table');
+phutil_require_module('phabricator', 'view/layout/panel');
+
+phutil_require_module('phutil', 'utils');
+
+
+phutil_require_source('PhabricatorDaemonConsoleController.php');

src/applications/timeline/storage/event/__init__.php

@@ -1,13 +0,0 @@
-<?php
-/**
- * This file is automatically generated. Lint this module to rebuild it.
- * @generated
- */
-
-
-
-phutil_require_module('phabricator', 'applications/timeline/storage/base');
-phutil_require_module('phabricator', 'applications/timeline/storage/eventdata');
-
-
-phutil_require_source('PhabricatorTimelineEvent.php');

src/infrastructure/daemon/timeline/cursor/iterator/__init__.php

@@ -6,9 +6,9 @@
 
 
 
-phutil_require_module('phabricator', 'applications/timeline/storage/cursor');
-phutil_require_module('phabricator', 'applications/timeline/storage/event');
-phutil_require_module('phabricator', 'applications/timeline/storage/eventdata');
+phutil_require_module('phabricator', 'infrastructure/daemon/timeline/storage/cursor');
+phutil_require_module('phabricator', 'infrastructure/daemon/timeline/storage/event');
+phutil_require_module('phabricator', 'infrastructure/daemon/timeline/storage/eventdata');
 phutil_require_module('phabricator', 'storage/queryfx');
 
 phutil_require_module('phutil', 'utils');

src/infrastructure/daemon/timeline/storage/cursor/__init__.php

@@ -6,7 +6,7 @@
 
 
 
-phutil_require_module('phabricator', 'applications/timeline/storage/base');
+phutil_require_module('phabricator', 'infrastructure/daemon/timeline/storage/base');
 
 
 phutil_require_source('PhabricatorTimelineCursor.php');

src/infrastructure/daemon/timeline/storage/event/__init__.php

@@ -0,0 +1,13 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'infrastructure/daemon/timeline/storage/base');
+phutil_require_module('phabricator', 'infrastructure/daemon/timeline/storage/eventdata');
+
+
+phutil_require_source('PhabricatorTimelineEvent.php');

src/infrastructure/daemon/timeline/storage/eventdata/__init__.php

@@ -6,7 +6,7 @@
 
 
 
-phutil_require_module('phabricator', 'applications/timeline/storage/base');
+phutil_require_module('phabricator', 'infrastructure/daemon/timeline/storage/base');
 
 
 phutil_require_source('PhabricatorTimelineEventData.php');

src/infrastructure/daemon/workers/storage/base/PhabricatorWorkerDAO.php

@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+abstract class PhabricatorWorkerDAO extends PhabricatorLiskDAO {
+  public function getApplicationName() {
+    return 'worker';
+  }
+}

src/infrastructure/daemon/workers/storage/base/__init__.php

@@ -0,0 +1,12 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'applications/base/storage/lisk');
+
+
+phutil_require_source('PhabricatorWorkerDAO.php');

src/infrastructure/daemon/workers/storage/task/PhabricatorWorkerTask.php

@@ -0,0 +1,60 @@
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+class PhabricatorWorkerTask extends PhabricatorWorkerDAO {
+
+  protected $taskClass;
+  protected $leaseOwner;
+  protected $leaseExpires;
+  protected $priority;
+  protected $failureCount;
+
+  private $serverTime;
+  private $localTime;
+
+  public function getConfiguration() {
+    return array(
+      self::CONFIG_TIMESTAMPS => false,
+    ) + parent::getConfiguration();
+  }
+
+  public function setServerTime($server_time) {
+    $this->serverTime = $server_time;
+    $this->localTime = time();
+    return $this;
+  }
+
+  public function setLeaseDuration($lease_duration) {
+    $server_lease_expires = $this->serverTime + $lease_duration;
+    $this->setLeaseExpires($server_lease_expires);
+    return $this->save();
+  }
+
+  public function save() {
+    if ($this->leaseOwner) {
+      $current_server_time = $this->serverTime + (time() - $this->localTime);
+      if ($current_server_time >= $this->leaseExpires) {
+        throw new Exception("Trying to update task after lease expiration!");
+      }
+    }
+
+    return parent::save();
+  }
+
+
+}

src/infrastructure/daemon/workers/storage/task/__init__.php

@@ -0,0 +1,12 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'infrastructure/daemon/workers/storage/base');
+
+
+phutil_require_source('PhabricatorWorkerTask.php');

src/infrastructure/daemon/workers/storage/taskdata/PhabricatorWorkerTaskData.php

@@ -0,0 +1,33 @@
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+class PhabricatorWorkerTaskData extends PhabricatorWorkerDAO {
+
+  protected $taskID;
+  protected $data;
+
+  public function getConfiguration() {
+    return array(
+      self::CONFIG_TIMESTAMPS => false,
+      self::CONFIG_SERIALIZATION => array(
+        'data' => self::SERIALIZATION_JSON,
+      ),
+    ) + parent::getConfiguration();
+  }
+
+}

src/infrastructure/daemon/workers/storage/taskdata/__init__.php

@@ -0,0 +1,12 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'infrastructure/daemon/workers/storage/base');
+
+
+phutil_require_source('PhabricatorWorkerTaskData.php');

src/infrastructure/daemon/workers/taskmaster/PhabricatorTaskmasterDaemon.php

@@ -0,0 +1,121 @@
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+class PhabricatorTaskmasterDaemon extends PhabricatorDaemon {
+
+  public function run() {
+    $lease_ownership_name = $this->getLeaseOwnershipName();
+
+    $task_table = new PhabricatorWorkerTask();
+    $taskdata_table = new PhabricatorWorkerTaskData();
+
+    $sleep = 0;
+    do {
+      $conn_w = $task_table->establishConnection('w');
+      queryfx(
+        $conn_w,
+        'UPDATE %T SET leaseOwner = %s, leaseExpires = UNIX_TIMESTAMP() + 15
+          WHERE leaseOwner IS NULL
+            OR leaseExpires < UNIX_TIMESTAMP()
+          ORDER BY leaseOwner IS NULL, failureCount, priority
+          LIMIT 1',
+          $task_table->getTableName(),
+          $lease_ownership_name);
+      $rows = $conn_w->getAffectedRows();
+
+      if ($rows) {
+        $data = queryfx_all(
+          $conn_w,
+          'SELECT task.*, taskdata.data _taskData, UNIX_TIMESTAMP() _serverTime
+            FROM %T task LEFT JOIN %T taskdata
+              ON taskdata.taskID = task.id
+            WHERE leaseOwner = %s AND leaseExpires > UNIX_TIMESTAMP()
+            LIMIT 1',
+          $task_table->getTableName(),
+          $taskdata_table->getTableName(),
+          $lease_ownership_name);
+        $tasks = $task_table->loadAllFromArray($data);
+        $tasks = mpull($tasks, null, 'getID');
+
+        $task_data = array();
+        foreach ($data as $row) {
+          $tasks[$row['id']]->setServerTime($row['_serverTime']);
+          if ($row['_taskData']) {
+            $task_data[$row['id']] = json_decode($row['_taskData'], true);
+          } else {
+            $task_data[$row['id']] = null;
+          }
+        }
+
+        foreach ($tasks as $task) {
+          // TODO: We should detect if we acquired a task with an expired lease
+          // and log about it / bump up failure count.
+
+          // TODO: We should detect if we acquired a task with an excessive
+          // failure count and fail it permanently.
+
+          $data = idx($task_data, $task->getID());
+          $class = $task->getTaskClass();
+          try {
+            PhutilSymbolLoader::loadClass($class);
+            if (!is_subclass_of($class, 'PhabricatorWorker')) {
+              throw new Exception(
+                "Task class '{$class}' does not extend PhabricatorWorker.");
+            }
+            $worker = newv($class, array($data));
+
+            $lease = $worker->getRequiredLeaseTime();
+            if ($lease !== null) {
+              $task->setLeaseDuration($lease);
+            }
+
+            $worker->executeTask();
+
+            $task->delete();
+            if ($data !== null) {
+              queryfx(
+                $conn_w,
+                'DELETE FROM %T WHERE taskID = %d',
+                $taskdata_table,
+                $task->getID());
+            }
+          } catch (Exception $ex) {
+            $task->setFailureCount($task->getFailureCount() + 1);
+            $task->save();
+            throw $ex;
+          }
+        }
+
+        $sleep = 0;
+      } else {
+        $sleep = min($sleep + 1, 30);
+      }
+
+      $this->sleep($sleep);
+    } while (true);
+  }
+
+  private function getLeaseOwnershipName() {
+    static $name = null;
+    if ($name === null) {
+      $name = getmypid().':'.time().':'.php_uname('n');
+    }
+    return $name;
+  }
+
+}

src/infrastructure/daemon/workers/taskmaster/__init__.php

@@ -0,0 +1,18 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'infrastructure/daemon/base');
+phutil_require_module('phabricator', 'infrastructure/daemon/workers/storage/task');
+phutil_require_module('phabricator', 'infrastructure/daemon/workers/storage/taskdata');
+phutil_require_module('phabricator', 'storage/queryfx');
+
+phutil_require_module('phutil', 'symbols');
+phutil_require_module('phutil', 'utils');
+
+
+phutil_require_source('PhabricatorTaskmasterDaemon.php');

src/infrastructure/daemon/workers/worker/PhabricatorWorker.php

@@ -0,0 +1,40 @@
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+abstract class PhabricatorWorker {
+
+  private $data;
+
+  final public function __construct($data) {
+    $this->data = $data;
+  }
+
+  final protected function getTaskData() {
+    return $this->data;
+  }
+
+  final public function executeTask() {
+    $this->doWork();
+  }
+
+  public function getRequiredLeaseTime() {
+    return null;
+  }
+
+  abstract protected function doWork();
+}

src/infrastructure/daemon/workers/worker/__init__.php

@@ -0,0 +1,10 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+
+phutil_require_source('PhabricatorWorker.php');

src/infrastructure/daemon/workers/worker/goodfornothing/PhabricatorGoodForNothingWorker.php

@@ -0,0 +1,28 @@
+<?php
+
+/*
+ * Copyright 2011 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Trivial example worker; processes tasks which require no work very slowly.
+ *
+ * @group worker
+ */
+class PhabricatorGoodForNothingWorker extends PhabricatorWorker {
+  protected function doWork() {
+    sleep(10);
+  }
+}

src/infrastructure/daemon/workers/worker/goodfornothing/__init__.php

@@ -0,0 +1,12 @@
+<?php
+/**
+ * This file is automatically generated. Lint this module to rebuild it.
+ * @generated
+ */
+
+
+
+phutil_require_module('phabricator', 'infrastructure/daemon/workers/worker');
+
+
+phutil_require_source('PhabricatorGoodForNothingWorker.php');

src/storage/lisk/dao/LiskDAO.php

@@ -442,6 +442,9 @@ abstract class LiskDAO {
    * @task   load
    */
   public function loadFromArray(array $row) {
+
+    // TODO: We should load only valid properties.
+
     $map = array();
     foreach ($row as $k => $v) {
       $map[$k] = $v;