$db['default'] = array(
    'dsn'   => 'mysql:unix_socket=/cloudsql/<instance-connection-name>;dbname=<data-base-name>',
    'hostname' => 'localhost',
    'username' => USERNAME,
    'password' => PASSWORD,
    'database' => DATABASE,
    'dbdriver' => 'pdo',
    'dbprefix' => '',
    'pconnect' => FALSE,
    'db_debug' => (ENVIRONMENT !== 'production'),
    'cache_on' => FALSE,
    'cachedir' => '',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'encrypt' => FALSE,
    'compress' => FALSE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => TRUE
);

runtime: php
env: flex

runtime_config:
    document_root: .

env_variables:
    MYSQL_USER: USER
    MYSQL_PASSWORD: PASSWORD
    MYSQL_DSN: mysql:dbname=<database>;unix_socket=/cloudsql/<instance-connection-name>

beta_settings:
    cloud_sql_instances: <instance-connection-name>