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MasterSlaveConnection.php
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MasterSlaveConnection.php
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<?php
declare(strict_types=1);
namespace Doctrine\DBAL\Connections;
use Doctrine\Common\EventManager;
use Doctrine\DBAL\Configuration;
use Doctrine\DBAL\Connection;
use Doctrine\DBAL\Driver;
use Doctrine\DBAL\Driver\Connection as DriverConnection;
use Doctrine\DBAL\Driver\ResultStatement;
use Doctrine\DBAL\Driver\Statement;
use Doctrine\DBAL\Event\ConnectionEventArgs;
use Doctrine\DBAL\Events;
use InvalidArgumentException;
use function array_rand;
use function assert;
use function count;
/**
* Master-Slave Connection
*
* Connection can be used with master-slave setups.
*
* Important for the understanding of this connection should be how and when
* it picks the slave or master.
*
* 1. Slave if master was never picked before and ONLY if 'getWrappedConnection'
* or 'executeQuery' is used.
* 2. Master picked when 'exec', 'executeUpdate', 'insert', 'delete', 'update', 'createSavepoint',
* 'releaseSavepoint', 'beginTransaction', 'rollback', 'commit', 'query' or
* 'prepare' is called.
* 3. If master was picked once during the lifetime of the connection it will always get picked afterwards.
* 4. One slave connection is randomly picked ONCE during a request.
*
* ATTENTION: You can write to the slave with this connection if you execute a write query without
* opening up a transaction. For example:
*
* $conn = DriverManager::getConnection(...);
* $conn->executeQuery("DELETE FROM table");
*
* Be aware that Connection#executeQuery is a method specifically for READ
* operations only.
*
* This connection is limited to slave operations using the
* Connection#executeQuery operation only, because it wouldn't be compatible
* with the ORM or SchemaManager code otherwise. Both use all the other
* operations in a context where writes could happen to a slave, which makes
* this restricted approach necessary.
*
* You can manually connect to the master at any time by calling:
*
* $conn->connect('master');
*
* Instantiation through the DriverManager looks like:
*
* @example
*
* $conn = DriverManager::getConnection(array(
* 'wrapperClass' => 'Doctrine\DBAL\Connections\MasterSlaveConnection',
* 'driver' => 'pdo_mysql',
* 'master' => array('user' => '', 'password' => '', 'host' => '', 'dbname' => ''),
* 'slaves' => array(
* array('user' => 'slave1', 'password', 'host' => '', 'dbname' => ''),
* array('user' => 'slave2', 'password', 'host' => '', 'dbname' => ''),
* )
* ));
*
* You can also pass 'driverOptions' and any other documented option to each of this drivers
* to pass additional information.
*/
class MasterSlaveConnection extends Connection
{
/**
* Master and slave connection (one of the randomly picked slaves).
*
* @var array<string, DriverConnection|null>
*/
protected $connections = ['master' => null, 'slave' => null];
/**
* You can keep the slave connection and then switch back to it
* during the request if you know what you are doing.
*
* @var bool
*/
protected $keepSlave = false;
/**
* Creates Master Slave Connection.
*
* @param array<string, mixed> $params
*
* @throws InvalidArgumentException
*/
public function __construct(
array $params,
Driver $driver,
?Configuration $config = null,
?EventManager $eventManager = null
) {
if (! isset($params['slaves'], $params['master'])) {
throw new InvalidArgumentException('master or slaves configuration missing');
}
if (count($params['slaves']) === 0) {
throw new InvalidArgumentException('You have to configure at least one slaves.');
}
$params['master']['driver'] = $params['driver'];
foreach ($params['slaves'] as $slaveKey => $slave) {
$params['slaves'][$slaveKey]['driver'] = $params['driver'];
}
$this->keepSlave = (bool) ($params['keepSlave'] ?? false);
parent::__construct($params, $driver, $config, $eventManager);
}
/**
* Checks if the connection is currently towards the master or not.
*/
public function isConnectedToMaster() : bool
{
return $this->_conn !== null && $this->_conn === $this->connections['master'];
}
public function connect(?string $connectionName = null) : void
{
$requestedConnectionChange = ($connectionName !== null);
$connectionName = $connectionName ?? 'slave';
if ($connectionName !== 'slave' && $connectionName !== 'master') {
throw new InvalidArgumentException('Invalid option to connect(), only master or slave allowed.');
}
// If we have a connection open, and this is not an explicit connection
// change request, then abort right here, because we are already done.
// This prevents writes to the slave in case of "keepSlave" option enabled.
if ($this->_conn !== null && ! $requestedConnectionChange) {
return;
}
$forceMasterAsSlave = false;
if ($this->getTransactionNestingLevel() > 0) {
$connectionName = 'master';
$forceMasterAsSlave = true;
}
if (isset($this->connections[$connectionName])) {
$this->_conn = $this->connections[$connectionName];
if ($forceMasterAsSlave && ! $this->keepSlave) {
$this->connections['slave'] = $this->_conn;
}
return;
}
if ($connectionName === 'master') {
$this->connections['master'] = $this->_conn = $this->connectTo($connectionName);
// Set slave connection to master to avoid invalid reads
if (! $this->keepSlave) {
$this->connections['slave'] = $this->connections['master'];
}
} else {
$this->connections['slave'] = $this->_conn = $this->connectTo($connectionName);
}
if (! $this->_eventManager->hasListeners(Events::postConnect)) {
return;
}
$eventArgs = new ConnectionEventArgs($this);
$this->_eventManager->dispatchEvent(Events::postConnect, $eventArgs);
}
/**
* Connects to a specific connection.
*/
protected function connectTo(string $connectionName) : DriverConnection
{
$params = $this->getParams();
$driverOptions = $params['driverOptions'] ?? [];
$connectionParams = $this->chooseConnectionConfiguration($connectionName, $params);
$user = $connectionParams['user'] ?? '';
$password = $connectionParams['password'] ?? '';
return $this->_driver->connect($connectionParams, $user, $password, $driverOptions);
}
/**
* @param array<string, mixed> $params
*
* @return array<string, mixed>
*/
protected function chooseConnectionConfiguration(string $connectionName, array $params) : array
{
if ($connectionName === 'master') {
return $params['master'];
}
$config = $params['slaves'][array_rand($params['slaves'])];
if (! isset($config['charset']) && isset($params['master']['charset'])) {
$config['charset'] = $params['master']['charset'];
}
return $config;
}
/**
* {@inheritDoc}
*/
public function executeUpdate(string $query, array $params = [], array $types = []) : int
{
$this->connect('master');
return parent::executeUpdate($query, $params, $types);
}
public function beginTransaction() : void
{
$this->connect('master');
parent::beginTransaction();
}
public function commit() : void
{
$this->connect('master');
parent::commit();
}
public function rollBack() : void
{
$this->connect('master');
parent::rollBack();
}
/**
* {@inheritDoc}
*/
public function delete(string $table, array $identifier, array $types = []) : int
{
$this->connect('master');
return parent::delete($table, $identifier, $types);
}
public function close() : void
{
unset($this->connections['master'], $this->connections['slave']);
parent::close();
$this->_conn = null;
$this->connections = ['master' => null, 'slave' => null];
}
/**
* {@inheritDoc}
*/
public function update(string $table, array $data, array $identifier, array $types = []) : int
{
$this->connect('master');
return parent::update($table, $data, $identifier, $types);
}
/**
* {@inheritDoc}
*/
public function insert(string $table, array $data, array $types = []) : int
{
$this->connect('master');
return parent::insert($table, $data, $types);
}
public function exec(string $statement) : int
{
$this->connect('master');
return parent::exec($statement);
}
public function createSavepoint(string $savepoint) : void
{
$this->connect('master');
parent::createSavepoint($savepoint);
}
public function releaseSavepoint(string $savepoint) : void
{
$this->connect('master');
parent::releaseSavepoint($savepoint);
}
public function rollbackSavepoint(string $savepoint) : void
{
$this->connect('master');
parent::rollbackSavepoint($savepoint);
}
public function query(string $sql) : ResultStatement
{
$this->connect('master');
assert($this->_conn instanceof DriverConnection);
$logger = $this->getConfiguration()->getSQLLogger();
$logger->startQuery($sql);
$statement = $this->_conn->query($sql);
$statement->setFetchMode($this->defaultFetchMode);
$logger->stopQuery();
return $statement;
}
public function prepare(string $sql) : Statement
{
$this->connect('master');
return parent::prepare($sql);
}
}