# Connection pool
A common connection pool based on Swoole is usually used as the database connection pool.
[](https://github.com/open-smf/connection-pool/releases)
[](https://secure.php.net)
[](https://packagist.org/packages/open-smf/connection-pool)
[](LICENSE)
## Requirements
| Dependency | Requirement |
| -------- | -------- |
| [PHP](https://secure.php.net/manual/en/install.php) | `>=7.0.0` |
| [Swoole](https://github.com/swoole/swoole-src) | `>=4.2.9` `Recommend 4.2.13+` |
## Install
> Install package via [Composer](https://getcomposer.org/).
```shell
composer require "open-smf/connection-pool:~1.0"
```
## Usage
> See more [examples](examples).
- Available connectors
| Connector | Connection description |
| -------- | -------- |
| CoroutineMySQLConnector | Instance of `Swoole\Coroutine\MySQL` |
| CoroutinePostgreSQLConnector | Instance of `Swoole\Coroutine\PostgreSQL`, require configuring `Swoole` with `--enable-coroutine-postgresql`|
| CoroutineRedisConnector | Instance of `Swoole\Coroutine\Redis` |
| PhpRedisConnector | Instance of `Redis`, require [redis](https://pecl.php.net/package/redis) |
| PDOConnector | Instance of `PDO`, require [PDO](https://www.php.net/manual/en/book.pdo.php) |
| YourConnector | `YourConnector` must implement interface `ConnectorInterface`, any object can be used as a connection instance |
- Basic usage
```php
use Smf\ConnectionPool\ConnectionPool;
use Smf\ConnectionPool\Connectors\CoroutineMySQLConnector;
use Swoole\Coroutine\MySQL;
go(function () {
// All MySQL connections: [10, 30]
$pool = new ConnectionPool(
[
'minActive' => 10,
'maxActive' => 30,
'maxWaitTime' => 5,
'maxIdleTime' => 20,
'idleCheckInterval' => 10,
],
new CoroutineMySQLConnector,
[
'host' => '127.0.0.1',
'port' => '3306',
'user' => 'root',
'password' => 'xy123456',
'database' => 'mysql',
'timeout' => 10,
'charset' => 'utf8mb4',
'strict_type' => true,
'fetch_mode' => true,
]
);
echo "Initializing connection pool\n";
$pool->init();
defer(function () use ($pool) {
echo "Closing connection pool\n";
$pool->close();
});
echo "Borrowing the connection from pool\n";
/**@var MySQL $connection */
$connection = $pool->borrow();
$status = $connection->query('SHOW STATUS LIKE "Threads_connected"');
echo "Return the connection to pool as soon as possible\n";
$pool->return($connection);
var_dump($status);
});
```
- Usage in Swoole Server
```php
use Smf\ConnectionPool\ConnectionPool;
use Smf\ConnectionPool\ConnectionPoolTrait;
use Smf\ConnectionPool\Connectors\CoroutineMySQLConnector;
use Smf\ConnectionPool\Connectors\PhpRedisConnector;
use Swoole\Coroutine\MySQL;
use Swoole\Http\Request;
use Swoole\Http\Response;
use Swoole\Http\Server;
class HttpServer
{
use ConnectionPoolTrait;
protected $swoole;
public function __construct(string $host, int $port)
{
$this->swoole = new Server($host, $port);
$this->setDefault();
$this->bindWorkerEvents();
$this->bindHttpEvent();
}
protected function setDefault()
{
$this->swoole->set([
'daemonize' => false,
'dispatch_mode' => 1,
'max_request' => 8000,
'open_tcp_nodelay' => true,
'reload_async' => true,
'max_wait_time' => 60,
'enable_reuse_port' => true,
'enable_coroutine' => true,
'http_compression' => false,
'enable_static_handler' => false,
'buffer_output_size' => 4 * 1024 * 1024,
'worker_num' => 4, // Each worker holds a connection pool
]);
}
protected function bindHttpEvent()
{
$this->swoole->on('Request', function (Request $request, Response $response) {
$pool1 = $this->getConnectionPool('mysql');
/**@var MySQL $mysql */
$mysql = $pool1->borrow();
$status = $mysql->query('SHOW STATUS LIKE "Threads_connected"');
// Return the connection to pool as soon as possible
$pool1->return($mysql);
$pool2 = $this->getConnectionPool('redis');
/**@var \Redis $redis */
$redis = $pool2->borrow();
$clients = $redis->info('Clients');
// Return the connection to pool as soon as possible
$pool2->return($redis);
$json = [
'status' => $status,
'clients' => $clients,
];
// Other logic
// ...
$response->header('Content-Type', 'application/json');
$response->end(json_encode($json));
});
}
protected function bindWorkerEvents()
{
$createPools = function () {
// All MySQL connections: [4 workers * 2 = 8, 4 workers * 10 = 40]
$pool1 = new ConnectionPool(
[
'minActive' => 2,
'maxActive' => 10,
],
new CoroutineMySQLConnector,
[
'host' => '127.0.0.1',
'port' => '3306',
'user' => 'root',
'password' => 'xy123456',
'database' => 'mysql',
'timeout' => 10,
'charset' => 'utf8mb4',
'strict_type' => true,
'fetch_mode' => true,
]);
$pool1->init();
$this->addConnectionPool('mysql', $pool1);
// All Redis connections: [4 workers * 5 = 20, 4 workers * 20 = 80]
$pool2 = new ConnectionPool(
[
'minActive' => 5,
'maxActive' => 20,
],
new PhpRedisConnector,
[
'host' => '127.0.0.1',
'port' => '6379',
'database' => 0,
'password' => null,
]);
$pool2->init();
$this->addConnectionPool('redis', $pool2);
};
$closePools = function () {
$this->closeConnectionPools();
};
$this->swoole->on('WorkerStart', $createPools);
$this->swoole->on('WorkerStop', $closePools);
$this->swoole->on('WorkerError', $closePools);
}
public function start()
{
$this->swoole->start();
}
}
// Enable coroutine for PhpRedis
Swoole\Runtime::enableCoroutine();
$server = new HttpServer('0.0.0.0', 5200);
$server->start();
```
## License
[MIT](LICENSE)