PrimaryReadReplicaConnection.php 11.5 KB
Newer Older
1 2 3 4 5 6 7
<?php

namespace Doctrine\DBAL\Connections;

use Doctrine\Common\EventManager;
use Doctrine\DBAL\Configuration;
use Doctrine\DBAL\Connection;
8
use Doctrine\DBAL\DBALException;
9 10
use Doctrine\DBAL\Driver;
use Doctrine\DBAL\Driver\Connection as DriverConnection;
11
use Doctrine\DBAL\Driver\DriverException;
12 13
use Doctrine\DBAL\Driver\Result;
use Doctrine\DBAL\Driver\Statement;
14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145
use Doctrine\DBAL\Event\ConnectionEventArgs;
use Doctrine\DBAL\Events;
use InvalidArgumentException;

use function array_rand;
use function assert;
use function count;
use function func_get_args;

/**
 * Primary-Replica Connection
 *
 * Connection can be used with primary-replica setups.
 *
 * Important for the understanding of this connection should be how and when
 * it picks the replica or primary.
 *
 * 1. Replica if primary was never picked before and ONLY if 'getWrappedConnection'
 *    or 'executeQuery' is used.
 * 2. Primary picked when 'exec', 'executeUpdate', 'insert', 'delete', 'update', 'createSavepoint',
 *    'releaseSavepoint', 'beginTransaction', 'rollback', 'commit', 'query' or
 *    'prepare' is called.
 * 3. If Primary was picked once during the lifetime of the connection it will always get picked afterwards.
 * 4. One replica connection is randomly picked ONCE during a request.
 *
 * ATTENTION: You can write to the replica 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.
 *
 * Use Connection#executeUpdate for any SQL statement that changes/updates
 * state in the database (UPDATE, INSERT, DELETE or DDL statements).
 *
 * This connection is limited to replica 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 replica, which makes
 * this restricted approach necessary.
 *
 * You can manually connect to the primary at any time by calling:
 *
 *      $conn->ensureConnectedToPrimary();
 *
 * Instantiation through the DriverManager looks like:
 *
 * @example
 *
 * $conn = DriverManager::getConnection(array(
 *    'wrapperClass' => 'Doctrine\DBAL\Connections\PrimaryReadReplicaConnection',
 *    'driver' => 'pdo_mysql',
 *    'primary' => array('user' => '', 'password' => '', 'host' => '', 'dbname' => ''),
 *    'replica' => array(
 *        array('user' => 'replica1', 'password', 'host' => '', 'dbname' => ''),
 *        array('user' => 'replica2', 'password', 'host' => '', 'dbname' => ''),
 *    )
 * ));
 *
 * You can also pass 'driverOptions' and any other documented option to each of this drivers to pass additional information.
 */
class PrimaryReadReplicaConnection extends Connection
{
    /**
     * Primary and Replica connection (one of the randomly picked replicas).
     *
     * @var DriverConnection[]|null[]
     */
    protected $connections = ['primary' => null, 'replica' => null];

    /**
     * You can keep the replica connection and then switch back to it
     * during the request if you know what you are doing.
     *
     * @var bool
     */
    protected $keepReplica = false;

    /**
     * Creates Primary Replica Connection.
     *
     * @param mixed[] $params
     *
     * @throws InvalidArgumentException
     */
    public function __construct(array $params, Driver $driver, ?Configuration $config = null, ?EventManager $eventManager = null)
    {
        if (! isset($params['replica'], $params['primary'])) {
            throw new InvalidArgumentException('primary or replica configuration missing');
        }

        if (count($params['replica']) === 0) {
            throw new InvalidArgumentException('You have to configure at least one replica.');
        }

        $params['primary']['driver'] = $params['driver'];
        foreach ($params['replica'] as $replicaKey => $replica) {
            $params['replica'][$replicaKey]['driver'] = $params['driver'];
        }

        $this->keepReplica = (bool) ($params['keepReplica'] ?? false);

        parent::__construct($params, $driver, $config, $eventManager);
    }

    /**
     * Checks if the connection is currently towards the primary or not.
     */
    public function isConnectedToPrimary(): bool
    {
        return $this->_conn !== null && $this->_conn === $this->connections['primary'];
    }

    /**
     * @param string|null $connectionName
     *
     * @return bool
     */
    public function connect($connectionName = null)
    {
        if ($connectionName !== null) {
            throw new InvalidArgumentException('Passing a connection name as first argument is not supported anymore. Use ensureConnectedToPrimary()/ensureConnectedToReplica() instead.');
        }

        return $this->performConnect();
    }

    protected function performConnect(?string $connectionName = null): bool
    {
        $requestedConnectionChange = ($connectionName !== null);
146
        $connectionName            = $connectionName ?? 'replica';
147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229

        if ($connectionName !== 'replica' && $connectionName !== 'primary') {
            throw new InvalidArgumentException('Invalid option to connect(), only primary or replica 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 replica in case of "keepReplica" option enabled.
        if ($this->_conn !== null && ! $requestedConnectionChange) {
            return false;
        }

        $forcePrimaryAsReplica = false;

        if ($this->getTransactionNestingLevel() > 0) {
            $connectionName        = 'primary';
            $forcePrimaryAsReplica = true;
        }

        if (isset($this->connections[$connectionName])) {
            $this->_conn = $this->connections[$connectionName];

            if ($forcePrimaryAsReplica && ! $this->keepReplica) {
                $this->connections['replica'] = $this->_conn;
            }

            return false;
        }

        if ($connectionName === 'primary') {
            $this->connections['primary'] = $this->_conn = $this->connectTo($connectionName);

            // Set replica connection to primary to avoid invalid reads
            if (! $this->keepReplica) {
                $this->connections['replica'] = $this->connections['primary'];
            }
        } else {
            $this->connections['replica'] = $this->_conn = $this->connectTo($connectionName);
        }

        if ($this->_eventManager->hasListeners(Events::postConnect)) {
            $eventArgs = new ConnectionEventArgs($this);
            $this->_eventManager->dispatchEvent(Events::postConnect, $eventArgs);
        }

        return true;
    }

    /**
     * Connects to the primary node of the database cluster.
     *
     * All following statements after this will be executed against the primary node.
     */
    public function ensureConnectedToPrimary(): bool
    {
        return $this->performConnect('primary');
    }

    /**
     * Connects to a replica node of the database cluster.
     *
     * All following statements after this will be executed against the replica node,
     * unless the keepReplica option is set to false and a primary connection
     * was already opened.
     */
    public function ensureConnectedToReplica(): bool
    {
        return $this->performConnect('replica');
    }

    /**
     * Connects to a specific connection.
     *
     * @param string $connectionName
     *
     * @return DriverConnection
     */
    protected function connectTo($connectionName)
    {
        $params = $this->getParams();

        $connectionParams = $this->chooseConnectionConfiguration($connectionName, $params);

230
        try {
231
            return $this->_driver->connect($connectionParams);
232 233 234
        } catch (DriverException $e) {
            throw DBALException::driverException($this->_driver, $e);
        }
235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260
    }

    /**
     * @param string  $connectionName
     * @param mixed[] $params
     *
     * @return mixed
     */
    protected function chooseConnectionConfiguration($connectionName, $params)
    {
        if ($connectionName === 'primary') {
            return $params['primary'];
        }

        $config = $params['replica'][array_rand($params['replica'])];

        if (! isset($config['charset']) && isset($params['primary']['charset'])) {
            $config['charset'] = $params['primary']['charset'];
        }

        return $config;
    }

    /**
     * {@inheritDoc}
     */
261
    public function executeUpdate(string $query, array $params = [], array $types = []): int
262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340
    {
        $this->ensureConnectedToPrimary();

        return parent::executeUpdate($query, $params, $types);
    }

    /**
     * {@inheritDoc}
     */
    public function beginTransaction()
    {
        $this->ensureConnectedToPrimary();

        return parent::beginTransaction();
    }

    /**
     * {@inheritDoc}
     */
    public function commit()
    {
        $this->ensureConnectedToPrimary();

        return parent::commit();
    }

    /**
     * {@inheritDoc}
     */
    public function rollBack()
    {
        $this->ensureConnectedToPrimary();

        return parent::rollBack();
    }

    /**
     * {@inheritDoc}
     */
    public function delete($tableName, array $identifier, array $types = [])
    {
        $this->ensureConnectedToPrimary();

        return parent::delete($tableName, $identifier, $types);
    }

    /**
     * {@inheritDoc}
     */
    public function close()
    {
        unset($this->connections['primary'], $this->connections['replica']);

        parent::close();

        $this->_conn       = null;
        $this->connections = ['primary' => null, 'replica' => null];
    }

    /**
     * {@inheritDoc}
     */
    public function update($tableName, array $data, array $identifier, array $types = [])
    {
        $this->ensureConnectedToPrimary();

        return parent::update($tableName, $data, $identifier, $types);
    }

    /**
     * {@inheritDoc}
     */
    public function insert($tableName, array $data, array $types = [])
    {
        $this->ensureConnectedToPrimary();

        return parent::insert($tableName, $data, $types);
    }

341
    public function exec(string $statement): int
342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377
    {
        $this->ensureConnectedToPrimary();

        return parent::exec($statement);
    }

    /**
     * {@inheritDoc}
     */
    public function createSavepoint($savepoint)
    {
        $this->ensureConnectedToPrimary();

        parent::createSavepoint($savepoint);
    }

    /**
     * {@inheritDoc}
     */
    public function releaseSavepoint($savepoint)
    {
        $this->ensureConnectedToPrimary();

        parent::releaseSavepoint($savepoint);
    }

    /**
     * {@inheritDoc}
     */
    public function rollbackSavepoint($savepoint)
    {
        $this->ensureConnectedToPrimary();

        parent::rollbackSavepoint($savepoint);
    }

378
    public function query(string $sql): Result
379 380 381 382 383 384 385
    {
        $this->ensureConnectedToPrimary();
        assert($this->_conn instanceof DriverConnection);

        $args = func_get_args();

        $logger = $this->getConfiguration()->getSQLLogger();
386 387
        if ($logger !== null) {
            $logger->startQuery($sql);
388 389
        }

390
        $statement = $this->_conn->query($sql);
391

392
        if ($logger !== null) {
393 394 395 396 397 398
            $logger->stopQuery();
        }

        return $statement;
    }

399
    public function prepare(string $sql): Statement
400 401 402
    {
        $this->ensureConnectedToPrimary();

403
        return parent::prepare($sql);
404 405
    }
}