Hook for database configuration plugin

Summary:
This permits individual deployments to better configure their
database configuration, e.g. to allow more dynamic configuration that reacts
to database moves or master/slave replication.

Test Plan:
Browse

Reviewed By: epriestley
Reviewers: Girish, epriestley
CC: aran, epriestley
Differential Revision: 183

conf/default.conf.php

@@ -111,13 +111,6 @@ return array(
   // The MySQL server to connect to.
   'mysql.host' => 'localhost',
 
-  // READ-ONLY database connection information
-  // If you have a read-only slave mysql server, then you can fill out the
-  // below fields. If not, duplicate the above information for the slave.
-  'mysql_slave.user' => 'root',
-  'mysql_slave.pass' => '',
-  'mysql_slave.host' => 'localhost',
-
 // -- Email ----------------------------------------------------------------- //
 
   // Some Phabricator tools send email notifications, e.g. when Differential

src/__phutil_library_map__.php

@@ -107,6 +107,7 @@ phutil_register_library_map(array(
     'DarkConsoleServicesPluginAPI' => 'aphront/console/plugin/services/api',
     'DarkConsoleXHProfPlugin' => 'aphront/console/plugin/xhprof',
     'DarkConsoleXHProfPluginAPI' => 'aphront/console/plugin/xhprof/api',
+    'DatabaseConfigurationProvider' => 'applications/base/storage/configuration',
     'DifferentialAction' => 'applications/differential/constants/action',
     'DifferentialAddCommentView' => 'applications/differential/view/addcomment',
     'DifferentialAttachController' => 'applications/differential/controller/attach',

src/applications/base/storage/configuration/DatabaseConfigurationProvider.php

@@ -0,0 +1,51 @@
+<?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 DatabaseConfigurationProvider {
+  private $dao;
+  private $mode;
+
+  public function __construct(LiskDAO $dao, $mode) {
+    $this->dao = $dao;
+    $this->mode = $mode;
+  }
+
+  public function getUser() {
+    return PhabricatorEnv::getEnvConfig('mysql.user');
+  }
+
+  public function getPassword() {
+    return PhabricatorEnv::getEnvConfig('mysql.pass');
+  }
+
+  public function getHost() {
+    return PhabricatorEnv::getEnvConfig('mysql.host');
+  }
+
+  public function getDatabase() {
+    return 'phabricator_'.$this->getDao()->getApplicationName();
+  }
+
+  final protected function getDao() {
+    return $this->dao;
+  }
+
+  final protected function getMode() {
+    return $this->mode;
+  }
+}

src/applications/base/storage/configuration/__init__.php

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

src/applications/base/storage/lisk/PhabricatorLiskDAO.php

@@ -20,18 +20,18 @@
 abstract class PhabricatorLiskDAO extends LiskDAO {
 
   public function establishConnection($mode) {
-    $mysql_key = 'mysql';
+    $conf_provider = PhabricatorEnv::getEnvConfig(
-    if ($mode == 'r') {
+      'mysql.configuration_provider', 'DatabaseConfigurationProvider');
-      $mysql_key = 'mysql_slave';
+    PhutilSymbolLoader::loadClass($conf_provider);
-    }
+    $conf = newv($conf_provider, array($this, $mode));
+
     return new AphrontMySQLDatabaseConnection(
       array(
-        'user'      => PhabricatorEnv::getEnvConfig($mysql_key.'.user'),
+        'user'      => $conf->getUser(),
-        'pass'      => PhabricatorEnv::getEnvConfig($mysql_key.'.pass'),
+        'pass'      => $conf->getPassword(),
-        'host'      => PhabricatorEnv::getEnvConfig($mysql_key.'.host'),
+        'host'      => $conf->getHost(),
-        'database'  => 'phabricator_'.$this->getApplicationName(),
+        'database'  => $conf->getDatabase(),
       ));
-
   }
 
   public function getTableName() {

src/applications/base/storage/lisk/__init__.php

@@ -10,5 +10,8 @@ phutil_require_module('phabricator', 'infrastructure/env');
 phutil_require_module('phabricator', 'storage/connection/mysql');
 phutil_require_module('phabricator', 'storage/lisk/dao');
 
+phutil_require_module('phutil', 'symbols');
+phutil_require_module('phutil', 'utils');
+
 
 phutil_require_source('PhabricatorLiskDAO.php');

src/storage/lisk/dao/LiskDAO.php

@@ -603,6 +603,9 @@ abstract class LiskDAO {
       throw new Exception("Unknown mode '{$mode}', should be 'r' or 'w'.");
     }
 
+    // TODO There is currently no protection on 'r' queries against writing
+    // or on 'w' queries against reading
+
     if (!isset($this->__connections[$mode])) {
       $this->__connections[$mode] = $this->establishConnection($mode);
     }