Flesh out the connection pool class.

app/composer.json

@@ -15,7 +15,8 @@
         "dotenv-org/phpdotenv-vault": "^0.2.4",
         "react/react": "^1.4",
         "robmorgan/phinx": "^0.16.1",
-        "react/mysql": "^0.7dev"
+        "react/mysql": "^0.7dev",
+        "react/async": "^4.3"
     },
     "require-dev": {
         "phpunit/phpunit": "^11.1",

app/composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "525ed6c2ef7a52e8447108c1427f1b7d",
+    "content-hash": "df12c4f8e3bfd8ecbaa4864a9d702c27",
     "packages": [
         {
             "name": "cakephp/chronos",

app/server/server.php

@@ -32,6 +32,3 @@ try {
     fprintf(STDERR, $e->getMessage() . "\n");
     return -1;
 }
-
-
-

app/src/Infrastructure/Api/Database/ConnectionPoolInterface.php

@@ -15,7 +15,13 @@ interface ConnectionPoolInterface
      * @return bool
      */
     public function hasIdleConnection(): bool;
-    public function setWaitTimeout(int $seconds): void;
+
+    /**
+     * Sets the new wait timeout for acquiring a connection.
+     *
+     * @param int $ms The amount of time in seconds.
+     */
+    public function setWaitTimeout(int $s): void;
     public function getWaitTimeout(): int;
     public function getConnectionLimit(): int;
 

app/src/Infrastructure/Database/ConnectionPool.php

@@ -2,65 +2,84 @@
 
 namespace Slovocast\Infrastructure\Database;
 
-use React\Mysql\MysqlClient;
 use Slovocast\Infrastructure\Api\Database\ConnectionPoolInterface;
 use Slovocast\Infrastructure\Api\Database\PooledConnectionInterface;
+use SplObjectStorage;
 
 class ConnectionPool implements ConnectionPoolInterface
 {
-    /**
-     * Set a default wait timeout for acquiring a connection to 100ms
-     */
-    const int DEFAULT_WAIT_TIMEOUT = 100;
-    private array $idleConnections;
-    private array $activeConnections;
+    private int $waitTimeout;
+    private SplObjectStorage $idleConnections;
+    private SplObjectStorage $activeConnections;
     private ConnectionPoolConfig $config;
 
     public function __construct(ConnectionPoolConfig $config)
     {
-        $this->config = $config;
-        for ($i = 0; $i < $config->getTotalConnections(); $i++) {
-            $this->idleConnections[] = new MysqlClient($this->config->getDsn());
+        $this->idleConnections = new SplObjectStorage();
+        $this->activeConnections = new SplObjectStorage();
+
+        for ($i = 0; $i < $this->config->getTotalConnections(); $i++) {
+            $pooledConnection = new PooledConnection($this->config->getDsnString());
+            $this->idleConnections->attach($$pooledConnection);
         }
+
+        $this->waitTimeout = $config->getPoolWaitTimeout();
     }
 
     public function getTotalIdleConnections(): int
     {
-        // TODO: Implement getTotalIdleConnections() method.
+        return $this->idleConnections->count();
     }
 
     public function getTotalActiveConnections(): int
     {
-        // TODO: Implement getTotalActiveConnections() method.
+        return $this->activeConnections->count();
     }
 
     public function hasIdleConnection(): bool
     {
-        // TODO: Implement hasIdleConnection() method.
+        return $this->idleConnections->count() > 0;
     }
 
-    public function setWaitTimeout(int $seconds): void
+    public function setWaitTimeout(int $s): void
     {
-        // TODO: Implement setWaitTimeout() method.
+        $this->waitTimeout = $s;
     }
 
     public function getWaitTimeout(): int
     {
-        // TODO: Implement getWaitTimeout() method.
+        return $this->waitTimeout;
     }
 
     public function getConnectionLimit(): int
     {
-        // TODO: Implement getConnectionLimit() method.
+        return $this->config->getTotalConnections();
     }
 
+    /**
+     * @TODO Throw an exception when a total timeout is exceeded. We do not want
+     *       to get into an infinite loop.
+     *
+     * @return PooledConnectionInterface
+     */
     public function getConnection(): PooledConnectionInterface
     {
-        // TODO: Implement getConnection() method.
+        if (!$this->hasIdleConnection()) {
+            \React\Async\delay((float) $this->getWaitTimeout());
+            return this->getConnection();
+        }
+
+        $conn = $this->idleConnections->current();
+        $this->idleConnections->detach($conn);
+        $this->activeConnections->attach($conn);
+        return $conn;
     }
 
     public function releaseConnection(PooledConnectionInterface $connection): void
     {
-        // TODO: Implement releaseConnection() method.
+        if ($this->activeConnections->contains($connection)) {
+            $this->activeConnections->detach($connection);
+            $this->idleConnections->attach($connection);
+        }
     }
 }

app/src/Infrastructure/Database/ConnectionPoolConfig.php

@@ -2,18 +2,19 @@
 
 namespace Slovocast\Infrastructure\Database;
 
-use React\Mysql\MysqlClient;
-
 class ConnectionPoolConfig
 {
+    const DEFAULT_WAIT_TIMEOUT = 60;
+    const DEFAULT_TOTAL_CONNECTIONS = 10;
+
     public function __construct(
         public readonly string $username,
         public readonly string $password,
         public readonly string $database,
         public readonly string $host,
         protected int $port = 3306,
-        protected int $poolWaitTimeout = ConnectionPool::DEFAULT_WAIT_TIMEOUT,
-        protected int $totalConnections = 10,
+        protected int $poolWaitTimeout = self::DEFAULT_WAIT_TIMEOUT,
+        protected int $totalConnections = self::DEFAULT_TOTAL_CONNECTIONS
     ) { }
 
     public function getPort(): int
@@ -31,7 +32,7 @@ class ConnectionPoolConfig
         return $this->totalConnections;
     }
 
-    public function getDsn(): string
+    public function getDsnString(): string
     {
         return sprintf(
             "%s:%s@%s/%s",