protected function formatVariables($key, array $values)
    {
        switch ($key) {
            case 'PHP_PECL':
                return $this->formatPeclPackages($values);
            case 'PHP_COMMANDS':
                return $this->formatRunCommand($values);
            case 'PHP_EXT_CONFIG':
            case 'PHP_EXT_ENABLE':
            case 'PHP_EXT_INSTALL':
            case 'PACKAGE_INSTALL':
                return $this->formatValueDelimiter($values);
        }
    }
protected function formatVariables($key, array $values)
    {
        switch ($key) {
            case 'PHP_PECL':
                return $this->formatPeclPackages($values);
            case 'PHP_COMMANDS':
                return $this->formatRunCommand($values);
            case 'PHP_EXT_CONFIG':
            case 'PHP_EXT_ENABLE':
            case 'PHP_EXT_INSTALL':
            case 'PACKAGE_INSTALL':
                return $this->formatValueDelimiter($values);
        }
    }
protected function formatVariables ( $ key , array $ values ) { switch ( $ key ) { case 'PHP_PECL' : return $ this -> formatPeclPackages ( $ values ) ; case 'PHP_COMMANDS' : return $ this -> formatRunCommand ( $ values ) ; case 'PHP_EXT_CONFIG' : case 'PHP_EXT_ENABLE' : case 'PHP_EXT_INSTALL' : case 'PACKAGE_INSTALL' : return $ this -> formatValueDelimiter ( $ values ) ; } }
Format docker variables.

@param $key
@param array $values
@return null|string
Format docker variables .