WP Dev with Docker

I got stuck for a bit today on how to configure a PHP PDO connection in a Docker based WordPress dev env. Here’s the function…

 * Get the database connection
 * @return \PDO database connection instance
public function get_connection() {
    $dbname = \TMSC\tmsc_sync()::$tms_db_name;
    $username = \TMSC\tmsc_sync()::$tms_db_user;
    $password = \TMSC\tmsc_sync()::$tms_db_password;
    // Build the DSN string
    $host = \TMSC\tmsc_sync()::$tms_db_host;
    $port = '3306';
    if ( strpos( $host, ':' ) ) {
        list( $host, $port ) = explode( ':', $host );

    $dsn = "mysql:host={$host};port={$port};dbname={$dbname}";

    $connection = new \PDO( $dsn, $username, $password, array(
    ) );

    // Since MySQL supports it, don't automatically quote parameters to allow control over data types.
    // This comes in useful for automatically manipulating the LIMIT clause.
    $connection->setAttribute( \PDO::ATTR_EMULATE_PREPARES, false );

    // Uncomment to enable connection debugging.
    $connection->setAttribute( \PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION );

    $this->set_mysql_global_defaults( $connection );
    return $connection;

When this function connects to a Remote AWS/RDS database, we configure it with a FQD for the $host variable. But, when running the same function locally, within our Docker setup, we must use the docker container name “jetpack_mysql” (as defined in the docker-compose.yml file) and not “” or “localhost”.